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1989 Petrography and geochemistry of volcanic rocks from Ungaran, Central Java, Indonesia Richard Claproth University of Wollongong
Recommended Citation Claproth, Richard, Petrography and geochemistry of volcanic rocks from Ungaran, Central Java, Indonesia, Doctor of Philosophy thesis, Department of Geology, University of Wollongong, 1989. http://ro.uow.edu.au/theses/1398
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PETROGRAPHY AND GEOCHEMISTRY OF VOLCANIC ROCKS FROM UNGARAN, CENTRAL JAVA, INDONESIA.
A thesis submitted in partial fulfilment of the requirements for the award of the degree of
DOCTOR OF PHILOSOPHY
from
THE UNIVERSITY OF WOLLONGONG
UNIVERSfTY OF | by WDU.ONGON3NGG I LIBRARY-J
RICHARD CLAPROTH, Ir. (ITB)
DEPARTMENT OF GEOLOGY 1988 1(uaBdik_m untuk. istrilQi tercinta, Marisa; anafcatiaklQi, %&ma, 9hya & Joshua; guru, dan sahaBatH_i, TauC. Except where otherwise acknowledged, this thesis represents the author's original research which has not previously been submitted to any institution in partial or complete fulfilment of another degree.
Richard Claproth ABSTRACT
The development of Java Island which forms part of the Sunda Arc is due to subduction of the northward-moving Indian-Australian Plate beneath the Eurasian Plate.
Ungaran volcano, Central Java, is situated 197 km above the Benioff Zone dipping at 55°, and forms part of the second of three cycles of volcanism recognized on Java Island. The volcano which was active between the Late Pliocene and Late Pleistocene is characterized by three stages of growth, interrupted by two episodes of cone collapse and the products of eruption can be grouped into four major units comprising Oldest Ungaran, Old
Ungaran, Parasitic Cones and Young Ungaran. Lavas consisting of basalts, basaltic andesites and andesites are porphyritic with either a holocrystalline or hypocrystalline groundmass. Plagioclase, clinopyroxene,
Fe-Ti oxide and amphibole are the major phenocrystic phases but biotite and olivine occur in some samples. In holocrystalline samples the phenocrysts are set in a fine-grained groundmass of feldspar, clinopyroxene, Fe-Ti oxide, and accessory apatite.
Plagioclase phenocrysts range in composition from oligoclase to anorthite and some grains have thin rims of K-feldspar. Compositions of phenocryst rims and-coexisting groundmass plagioclase are similar but the groundmass grains have a more restricted range in compositions. With increasing age the plagioclase phenocrysts in all'rock types from Ungaran become less calcic. Clinopyroxene (diopside, augite and salite)Hs the only pyroxene in lavas from Ungaran and small changes in the compositions of phebocrysts in the series basalt to basaltic andesite to andesite are attributed to increasing silica activity and decreasing pressure. Magnetite is the only Fe-Ti oxide in all lavas from Ungaran.
Most of the amphibole grains are magnesian-hastingsite and aggregates of "black amphibole" indicate conditions of rapid cooling at pressures less than 9 Kb. Biotite is a common accessory phase in basaltic andesites and andesites but is absent from basalts.
Most of the fresh olivine occurs in basalts from Old Ungaran and it has a compositional range from F059 to F079.
Lavas from Ungaran exhibit a continuum of compositions which range from 48.95% to 60.80% Si02. On the basis of K20 and Si02 contents, most of the basalts are shoshonites whereas most of the basaltic andesites and all andesites are
high-K calcalkaline. Shoshonitic rocks dominated the early stages of magmatic activity
whereas high-K calcalkaline rocks were produced during later stages. Compared with
most rocks of similar SiC>2 content, the lavas from Ungaran are characterized by high
contents of AI2O3 and total alkalies, high ferric/ferrous iron ratio, high contents of
incompatible elements and low MgO contents. Mafic rocks from Ungaran range from Ne-
normative to Q-normative depending on the ferric/ferrous iron used in the calculation.
Most of the basalt samples, however, are saturated if an assumed ratio of 0.2 for
Fe203/FeO+Fe203 is used but all are relatively evolved with a maximum Mg-number of
0.55. The low Mg-numbers indicate that these basalts crystallized from derivative melts
, and do not represent primary, mantle-derived magma.
Trace element modelling on the basis of published distribution coefficients and
possible source compositions suggests that the rocks from Ungaran are generated by
5 to 10% melting of spinel lherzolite or amphibole lherzolite which had been previously
enriched in incompatible elements. Subsequent to generation, 31.5 to 39.5% fractionation
of early formed olivine and clinopyroxene in a ratio 30/70 produced the most mafic rocks
in Ungaran.
Rocks with < 53% S-O2 have a wider range and higher mean 87Sr/86Sr ratio than
^rocks with > 53% SiC_ and the available isotopic data are consistent with derivation of
^Ungaran lavas from heterogeneous OIB-type source. Depletion of Ta, Nb and Ti relative
fto LILE cannot be attributed to a residual Ti-rich phase in the source. Geochemical data
are consistent with enrichment of LILE in the mantle wedge by the process of zone
• refining or mantle metasomatism, or from a fluid derived from the subducted slab.
Comparison between Sr isotopic ratios and contents of HFSE and LILE in Ungaran
basalts and the crust of the eastern Indian Ocean suggests that the model involving
derivation of Ungaran lavas from a mantle wedge contaminated by a fluid from the
subducted slab is plausible. Many observed geochemical variations in Ungaran lavas,
particularly in 87Sr/86Sr ratios, reflect heterogeneity in an OIB-type mantle wedge. ACKNOWLEDGEMENTS
I wish to express my appreciation to my supervisor Dr P.F. Carr for his help, guidance, patience and encouragement throughout this project. Professor A.C. Cook generously provided access to all facilities in the Department of Geology. Several staff from the CSIRO particularly Dr D.J. Whitford and J. Fardy who carried out the isotopic and instrumental neutron activation analyses deserve special recognition. I also wish to express my appreciation to N. Ware from the Research
School of Earth Sciences, Australian National University and Dr B.E. Chenhall from the
Department of Geology, University of Wollongong, who provided invaluable assistance with the electron microprobe and whole-rock X-ray fluorescence analyses. I have benefitted from fruitful discussions with many people, especially
Drs R. Cas, R.A. Day, J. Foden, F.A. Frey, M. McCulloch, LA. Nicholls,
G.E. Wheller and D.J. Whitford I am grateful to Dr C. Gray for his permission to use his unpublished data and for his comments on heterogeneity of the mantle. Numerous other friends provided advice during informal discussions, particularly M. Barsdell,
R. Sukhyar and D. Vukadinovic. Special appreciation is addressed to a fellow postgraduate student, Carol Simpson, who tirelessly helped in editing and correcting the English expression of my earlier draft.
Technical assistance from staff of the University of Wollongong, especially D.A. Carrie, A.M. Depers, D. Martin, L. Morris, J. Paterson, M. Perkins and
R. Varga is gratefully acknowledged. Associate Professor G. Doherty and T. Ratkolo are thanked for generously providing access to computing facilities.
Financial aid was provided by the Australian International Development Assistance Bureau and many people from this organisation, particularly N. McPherson, K. Moran, W. Rush, P. Schnelling and D. Wise, have my gratitude.
Finally I would like to acknowledge the support of my family especially my mother and sisters, and my spiritual parents Jess and Walter, for their constant assistance and encouragement during the preparation of this thesis. TABLE OF CONTENTS
Abstract Acknowledgements Page CHAPTER 1 INTRODUCTION 1.1 Introduction 1 1.2 Previous work 2 1.3 Aim of study 3 1.4 Thesis organisation 3 1.5 Data presentation 4 1.6 Rock nomenclature 5
CHAPTER 2 TECTONIC AND GEOLOGICAL SETTING 2.1 Introduction 7 2.2 Sunda Arc 8 2.3 Java Island 9 2.3.1 BenioffZone 9 2.3.2 Java Trench 10 2.3.3 Outer arc, ridge 10 2.3.4 Outer arc basin 10 2.3.5 Magmatic arc 11 2.3.6 Back arc 11 2.3.7 Stratigraphy 11 2.4 Central Java 12 2.4.1 Magmatic evolution 13 2.4.2 BenioffZone dip 14 2.4.3 Rate of convergence 15 2.5 Ungaran 16 2.5.1 Oldest Ungaran 16 2.5.2 Old Ungaran 17 2.5.3 Parasitic Cones 18 2.5.4 Young Ungaran 19 2.5.5 Dating and correlation 19 2.6 Summary CHAPTER 3 PETROGRAPHY AND MINERAL CHEMISTRY 3.1 Introduction 23 3.2 Oldest Ungaran 23 3.2.1 Basalt 23 3.2.2 Andesite 25 3.3 Old Ungaran 26 3.3.1 Basalt 26 3.3.2 B asaltic andesite 27 3.3.3 Andesite 29 3.4 Parasitic Cones 30 3.4.1 Basalt 30 3.4.2 Basaltic andesite 31 3.4.3 Andesite 33 3.5 Young Ungaran 35 3.5.1 Basalt 35 3.5.2 Basaltic andesite 37 3.5.3 Andesite 38 3.6 Summary and discussion 39 3.6.1 Plagioclase 40 3.6.2 Pyroxene 42 3.6.3 Fe-Ti oxide 44 3.6.4 Amphibole 44 3.6.5 Mica 45 3.6.6 Olivine 46 3.6.7 Order of crystallisation 47 3.6.8 Pressure and temperature of crystallisation 49
CHAPTER 4 TOTAL-ROCK GEOCHEMISTRY 4.1 Introduction 53 4.2 Geochemical features and variation 53 4.2.1 Oldest Ungaran 54 4.2.2 Old Ungaran 56 4.2.3 Parasitic Cones 59 4.2.4 Young Ungaran 61 4.3 Summary and discussion 63 4.3.1 Major elements 63 4.3.2 Strontium 64 4.3.3 Rubidium 65 4.3.4 Th, Pb, Zr, Hi, Y, Nb, Ta and Ti 67 4.3.5 Co, V, Sc and Cr 68 4.3.6 Rare earth elements 69 4.3.7 Strontium isotopes 70 4.3.8 Temporal variations and models for magma chamber 71 CHAPTER 5 MAGMATIC AFFINITIES 5.1 Introduction 75 5.2 Shoshonites 76 5.3 High-K calcalkaline rocks 77 5.4 Comparison of shoshonitic and high-K calcalkaline rocks from Ungaran 79 5.5 Comparison with other shoshonitic rocks 79 5.5.1 Basalts 80 5.5.2 Basaltic andesites 80 5.6 Comparison with other high-K calcalkaline rocks 81 5.6.1 Basalts 81 5.6.2 Basaltic andesites 82 5.6.3 Andesites 83 5.7 Summary 83
CHAPTER 6 PETROGENESIS 6.1 Introduction 87 6.2 Crust as the source region 88 6.3 Subducted lithosphere as the source region 89 6.4 Mantle as the source region 90 6.4.1 Primary and derivative magmas 90 6.4.2 Fractionation model and major element composition of the primary magma 92 6.4.3 REE concentration in the primary magma 94 6.4.4 Degree of partial melting 97 6.4.5 REE concentration in the mantle source 98 6.5 Model for magma genesis 100 6.5.1 MORB-and OIB-type sources 100 6.5.2 Pb isotopes 102 6.5.3 Nd isotopes 103 6.5.4 Possible causes of Sr isotopic variation in Ungaran 104 6.5.5 Mantle metasomatism 107 6.5.6 Model for HFSE depletion and LILE enrichment 108 6.6 Summary 112
CHAPTER 7 CONCLUSIONS 7.1 Conclusions 115
REFERENCES 127 FIGURES TO CHAPTER 1 153 FIGURES TO CHAPTER 2 155 FIGURES TO CHAPTER 3 168 FIGURES TO CHAPTER 4 211 FIGURES TO CHAPTER 5 263 FIGURES TO CHAPTER 6 269
TABLES TO CHAPTER 2 291 TABLES TO CHAPTER 3 292 TABLES TO CHAPTER 4 344 TABLES TO CHAPTER 5 365 TABLES TO CHAPTER 6 373
APPENDICES A METHODS OF INVESTIGATION 383 B MODAL MINERALOGY 387 C MINERAL CHEMISTRY 393 D TOTAL-ROCK CHEMISTRY 462 E CIPW NORMATIVE MINERALOGY 473 F PROGRAM TO CALCULATE PRIMARY MAGMA COMPOSITION
BY ADDING OLrvTNE OF COMPOSITION Fo90 479 G PROGRAM TO CALCULATE PRIMARY MAGMA COMPOSITION
BY ADDING OLIVINE OF COMPOSITION Fo90 AND
CLINOPYROXENE 482 H DISTRIBUTION COEFFICIENTS 435
I PETMIX CALCULATIONS 486 1
CHAPTER 1
INTRODUCTION
1.1 Introduction
Island arc volcanism has played a major part in the growth of continents throughout at least the Phanerozoic and a thorough understanding of the processes involved in the generation of island arc magmas is important in understanding the evolution of the earth. Many workers (e.g. Rittmann, 1953; Kuno, 1966;
Sugimura, 1968; Jakes and White, 1970; Gill, 1981; Arculus and Johnson, 1981;
Hutchison, 1982; Wheller et al., 1987) have documented gradational changes in the geochemistry of volcanic rocks both across and along island arcs, and with the advent of plate tectonic theory, the petrogenetic processes involved in the evolution of island arcs are of major interest
Spatial variations in the geochemistry of Pleistocene and Recent lavas from the Sunda Arc of Indonesia have been documented by Whitford (1975a). Within this arc, a clear association between subduction and volcanism is indicated by the geochemistry of volcanoes on Java Island where magmas range from tholeiitic near the trench to calcalkaline and alkaline farther from the trench. However, no detailed studies of the temporal variations in the geochemistry of individual volcanoes in
Java have been published.
Ungaran volcano which is one of the few high-K calcalkaline volcanoes of the Sunda Arc is situated in Central Java, Indonesia. This Quaternary volcano is underlain by a basement of Tertiary sedimentary strata and the depth to the Benioff
Zone in this region is approximately 200 km (Fig. 1-1). The tectonic setting, together with the distribution and stratigraphy of the products of Ungaran, have been documented by previous workers and make this dormant volcano an ideal subject for a detailed study of its evolution. 2
1.2 Previous work
The earliest known record of petrological work in the Ungaran area is that of
Verbeek and Fennema (1896), whereas the first detailed description of the geology
of the Ungaran area was given by van Bemmelen (1941) who noted three
successive periods of growth of Ungaran volcano punctuated by episodes of cone
collapse. He dealt mainly with the study of the Ungaran fault system, but also
presented data on the stratigraphy, petrography and total-rock geochemistry. Van
Bemmelen's work has provided a sound basis for more recent studies of tectonism
and volcanism in Central Java.
The Geological Survey of Indonesia, in cooperation with the United States
Geological Survey, has published a geological map of the northern part of Central
Java which includes Ungaran, Dieng, Sumbing and Sundoro volcanoes
(Thaden et al., 1975). Seven regionally mappable units are shown for the Ungaran
area on the 1:100,000 geological map, and except for the addition of structural
lineaments observed on aerial photographs, the geology depicted on this more
recent map is similar to that of van Bemmelen (1941).
The most comprehensive investigation of the petrography and geochemistry
of the volcanoes of Java Island was undertaken by Whitford (1975a) who has
published a series of papers including Whitford (1975b), Whitford and Nicholls
(1976), Whitford et al. (1979a, 1979b), Nicholls and Whitford (1976, 1978, 1983)
and Nicholls et al. (1980). These publications deal with regional geochemical
variations in Java but do not include a detailed study of within volcano variations.
Whitford et al. (1979a) concluded that the primary high-K calcalkaline magmas on
Java Island could be formed by 5 to 10% partial melting of peridotite mantle at a depth of between 40 and 60 km. They also demonstrated that both the 87Sr/86Sr ratio
and K20 at 55% Si02 increase with increasing depth to the Benioff Zone. Whitford
(1975a, 1975b) studied several samples from Ungaran and concluded that although the lavas from this volcano have been erupted over a relatively short time and are closely related geochemically, significant differences occur in the 87Sr/86Sr ratios of 3
these lavas. He suggested that a detailed study of within volcano geochemical variations was warranted to determine the petrogenesis of magma beneath Java.
In 1984 the Volcanological Survey of Indonesia investigated the possibility of geothermal power generation from Ungaran, which is regarded as a B-type volcano (volcano in solfatara and fumarole stage; van Bemmelen, 1949). The
Bouguer anomaly map of Untung and Sudarmo (1975) shows a lineament between
Ungaran and Muria volcanoes and detailed geological mapping of the area by
Muhardjo et al. (1984) has demonstrated a linear relationship with other volcanoes in Central Java (i.e. Dieng, Sumbing and Muria). Sanny (1985) proposed that if this lineament is an active fault, it is possible that Ungaran volcano may become active again.
1.3 Aim of study
The aim of the present study is to develop a model for the petrogenesis of lavas erupted from Ungaran volcano and to determine how this model compares with published accounts for the petrogenesis of rocks in island arcs. This necessitates consideration of the folowing features:
(a) the petrography, mineral chemistry and total-rock geochemistry of lavas
from Ungaran;
(b) temporal variations in petrography and geochemistry;
(c) magmatic affinities of these lavas; and
(d) relationships between these lavas.
1.4 Thesis organisation
This thesis is divided into four major parts. Part 1 presents background information for the study and comprises the introduction (Chapter 1), the geological setting of Sunda Arc and Java Island, and summarizes the available data on the stratigraphy of Ungaran volcano (Chapter 2). 4
Part 2 presents observations and deals with the petrography and mineral chemistry (Chapter 3), total-rock major and trace element chemistry, and isotopic compositions of the analysed samples (Chapter 4). Some general discussions of these observations are presented in these chapters. The magmatic affinities of
Ungaran volcano, Java Island, are discussed and comparisons with high-K calcalkaline and shoshonitic suites from other areas in the world are also presented
(Chapter 5).
Part 3 deals with the problem of island arc magma genesis, reviewing some of the more important features of the geochemistry of Ungaran lavas. An attempt is made to place constraints on possible petrogenetic models by using isotopic, trace and major element geochemical data. Some of the more widely accepted models for island arc magma sources and genesis are discussed in this context (Chapter 6).
Part 3 also includes a discussion of some of the wider implications of single volcano geochemical studies and presents conclusions (Chapter 7).
Part 4 comprises figures, tables and appendices. The methods of investigation and analytical techniques are presented in Appendix A whereas
Appendices B and C list the modal mineralogy and mineral chemistry. Appendices
D and E list representative whole-rock major and trace element data and CIPW normative mineralogy. The procedure to calculate primary magma composition are listed in Appendices F (for olivine addition) and G (for olivine and clinopyroxene addition). Appendix H gives the distribution coefficients used in REE modelling and Appendix I lists the petmix calculations.
1.5 Data presentation
Methods, precision and standards for all analytical data are included in
Appendix A. With the exception of amphibole and mica, major element contents of all rock and mineral analyses are expressed as weight percent and have been recalculated to 100% on a volatile free basis, but the original total is listed. Trace element contents are expressed in parts per million (ppm). 5
Because the oxidation state of Fe in lava at the time of crystallisation can be changed by many process subsequent to solidification, total Fe is reported as FeO, but the FeiO^eO ratio determined bytitration is also listed.
The Mg-number is defined as Mg/Mg+Fe2+ and in this thesis the ferrous
iron content used in the calculation is based on the equation Fe203/Fe203+FeO =
0.2 (e.g. Hughes and Hussey, 1976).
1.6 Rock nomenclature
Chemical parameters are used as a basis for rock classification because the
fine-grained nature of the groundmass of many lava flows from Ungaran volcano
precludes accurate determination of the modal mineralogy.
Potassium contents in rocks from Sunda Arc display the widest range for
any subduction-related tectonic setting, and on the basis of increasing K20 content,
rocks of the Indonesian Archipelago have been divided arbitrarily into tholeiitic,
calcalkaline, high-K calcalkaline, shoshonitic and leucititic series (cf. Peccerillo and
Taylor, 1976a; Wheller et al., 1987). The shoshonitic and leucititic series in this
nomenclature is synonymous with the high-K alkaline series of Whitford et al.
(1979a). A further division on the basis of Si02 content separates members of each
series into basalt, basaltic andesite and andesite (Fig. 1-2). 6 7
CHAPTER 2
TECTONIC AND GEOLOGICAL SETTING
2.1 Introduction
The Indonesian Archipelago has long been regarded as one of the classic areas of active volcanism. A close relationship between volcanism and tectonism is displayed by all 128 active volcanoes in the region. Islands of the Archipelago are developing in response to the complex interaction between the southward-moving
Eurasian Plate, the northward-moving Indian-Australian Plate and the westward-moving Pacific Plate (Fig. 2-1). The Java Trench and Timor Trough represent the major area of collision between the Eurasian and Indian-Australian
Plate whereas the Sorong Fault indicates the area of interaction between the Pacific and Indian-Australian Plates.
Subduction of the Indian-Australian Plate beneath the Eurasian Plate has led to the development of a major magmatic arc system which is subdivided into two segments comprising the Sunda Arc in the west and the Banda Arc in the east
(Fig. 2-2). The unusual hooked shape of the Banda Arc results from the westward movement of the Pacific Plate (Fig. 2-1).
The geological evolution of Indonesia is characterized by an evolving system of island arcs which are now represented by a series of linear igneous complexes and associated sedimentary deposits (Katili, 1973a; Hamilton, 1979).
From at least the Permian, these island arcs have been associated with a series of subduction zones which have migrated with time in response to changes in the tectonic setting of the region (Fig. 2-3). In contrast to the geological evolution of western Indonesia that has been relatively simple since at least the Early Tertiary, the geological history of Eastern Indonesia appears to have been much more complex as a result of the complicated interaction between three lithosperic plates
(Hamilton, 1979; Bowin et al., 1980; Silver et al., 1985). 8
2.2 Sunda Arc
The Sunda Arc extends from the northern tip of Sumatra to a point approximately 4000 km west of Timor and its present configuration is marked by two concentric ridges capped by many islands. The inner ridge, which joins the large islands of Sumatra and Java to the small islands of Bali, Lombok, Sumbawa and Flores, has been the scene of volcanic activity throughout the Cenozoic. Near
Sumatra, the outer ridge is characterized by many small islands, mostly rising only a few hundred meters above sea level, whereas in the vicinity of Java, Bali,
Lombok and Flores, this ridge is wholly submarine.
Geological and geophysical data indicate that the crust beneath the Sunda
Arc varies widely in both composition and thickness. Sumatra, which lies at the western end of the Sunda Arc, contains widespread Quaternary ignimbrites resulting from large eruptions (e.g. Toba), but the island is characterized by an overall low volcanic frequency, and a lack of deep focus earthquakes (up to
200 km; Fitch, 1970). The presence of Palaeozoic granites and pelitic schists
(van Bemmelen, 1949), and a crustal thickness of 20 to 30 km (Cummings and
Schiller, 1971; Kieckhefer et al., 1980) indicate that Sumatra is underlain by continental crust. In contrast, Java contains minor ignimbrite and is characterized
by an overall high volcanic frequency with deep focus earthquakes (up to 680 km;
Fitch and Molnar, 1970). According to Ben Avraham and Emery (1973) the crustal
thickness in Java is 20 to 25 km which thins to approximately 15 km beneath the
Flores Sea. This thickness is considered by Curray et al. (1977) as being
transitional between typical oceanic and continental crust thicknesses.
Although Sumatra and Java have similar tectonic elements (e.g. Hamilton,
1979), geochemical data suggest that the attitude of the Benioff Zone differs. For
example, the potassium content in Java increases towards the back arc region
(e.g. Hatherton and Dickinson, 1969), whereas no highly potassic island arc
volcanism occurs in Sumatra. This pattern may support the theory that the Benioff
Zone in Sumatra does not penetrate as deep as in Java. In addition, the west to east 9
decrease in 87Sr/86Sr ratios of volcanic rocks from Java may indicate the presence of thicker and more silicic crust towards the west (Whitford, 1975b).
2.3 Java Island
Java Island, as part of the Sunda Arc, exhibits geological and geophysical features typical of many island arcs. Three seismic layers comprising a shallow, intermediate and a deep layer have been recognized beneath Java Island (Fig. 2-4).
The shallow layer is up to 18 km thick and is composed of both Pliocene to Eocene sediments with low seismic velocities (up to 2.8 km/s) and metamoiphic or granitic rocks with seismic velocities up to 5.4 km/s. Gabbro or basalt which have a seismic velocity up to 6.6 km/s comprise the intermediate layer. The deep layer is characterized by a seismic velocity greater that 7.8 km/s and is composed of iiltramafic rocks (Fig. 2-4).
Perpendicular to the east-west trend of Java Island the plate tectonic elements indicated by the geophysical data (Fig. 2-4) comprise the Java Trench
(in the south), the fore arc composed of the outer arc ridge and basin, the magmatic arc, and the back arc.
2.3.1 Benioff Zone
The Benioff Zone dips northwards very gently to a depth of about 100 km over a lateral distance of approximately 200 km from the Java trench (Fig. 2-4).
The dip increases to approximately 65° beneath Java Island and the Java Sea, reaching a maximum depth of about 650 km (Hamilton, 1979). Measured down dip the seismic zone is 800 km long, and the horizontal width is approximately 500 km
(Fitch, 1970; Hamilton, 1979). The oceanic crust of the Indian Ocean is currently being subducted beneath Java Island at a rate of approximately 6 cm/y
(Le Pichon, 1968). 10
2.3.2 Java Trench
The Java Trench which formed by subduction of Late Cretaceous oceanic
crust (Heirtzler et al., 1978) with a thin (300 - 400 m) cover of pelagic sediments
(Moore et al., 1978) has a maximum depth of 7 km. This trench is characterized by
a large negative gravity anomaly (van Bemmelen, 1949), which is interpreted by
Hamilton (1979) to be an indication of sinking of relatively high density oceanic
lithosphere.
2.3.3 Outer arc ridge
The outer arc ridge is the crest of the continental slope rising from the Java
Trench, formed by imbrication of sediments and melanges in a wedge thickening
landwards (Fig. 2-4). The base of the wedge has an overall dip of 7° landwards,
whereas the continental slope represents the top of the wedge and has a dip of 3° to
4° oceanwards (Beck and Lehner, 1974). Oceanic crust thus slides very gently
beneath the continental slope of Java. Hamilton (1979) noted that the position of the
outer arc ridge in Java is controlled mainly by the outer edge of the over-riding plate
which provides the necessary buttress for the piling up of sediments and melanges.
2.3.4 Outer arc basin
The outer arc basin situated between the outer arc ridge and Java Island is
between 3 and 4 km deep and contains 4 to 5 km of sediment derived from the
island (Moore et al., 1978). Away from the outer arcridge toward s the basin itself
the sediments are more deformed with some overturned structures (Hamilton,
1979). Geothermal gradients are very low, approximately 2° to 3°C/100 m
(Kenyon and Beddoes, 1977). Presumably, this low gradient is caused by the
subduction of relatively cold oceanic crust beneath Java Island. 11
2.3.5 Magmatic arc
Across the magmatic arc, that is from the south to the north of Java,
Quaternary lavas of the "normal island arc association" (Whitford et al., 1979a) range from tholeiites to dominant calcalkaline lavas to high-K calcalkaline lavas over a Benioff Zone ranging from 100 to 250 km deep (Fig. 1-1). The leucititic suite occurs over Benioff Zone depths of about 400 km (Fig. 1-1). This Quaternary magmatic arc is represented by a slight positive gravity anomaly (Untung and
Sudarmo, 1975) and high heat flow which is typical of many magmatic arcs
(cf. Sugimura and Uyeda, 1973).
An interesting feature of the magmatic arc is the existence of intense faulting and folding. Tjia (1966) and Posavec et al. (1973) have noted a close relationship between the magmatic belt and large scale faulting, and Bahar and Girod (1983), on the basis of their study of the regional stress in Sumatra and Java, concluded that faults have controlled the location of volcanoes within the magmatic arc.
2.3.6 Back arc
During the Oligocene transgression or subsidence occurred and two aligned basins, the West Java and Madura Basins developed in the back arc region. Large thickness of sediments (approximately 6 km; Kusumadinata, 1978) were deposited in these basins prior to their emergence which began in the Miocene in the south, and advanced northwards during the Pliocene.
2,3.7 Stratigraphy
Little is known of the exposed pre-Tertiary rocks of Java Island although pre-Eocene rocks have been reported in Central Java (e.g. Ketner et al., 1976).
However, oil exploration in Indonesia has contributed data for the basement rocks beneath the Java Sea and Indian Ocean. In general, the basement of Java comprises metasedimentary rocks of terrigenous or volcanic origin and K-Ar dating indicates ages between 58 and 140 Ma (Katili, 1973b; Hamilton, 1979). 12
Paleogene sedimentary rocks constitute only 1 to 2% of the outcrop on Java
(e.g. Effendi, 1974; Condon et al., 1975). The Paleogene series began during the
Eocene-Oligocene with the deposition of marl, conglomerate, quartz sandstone,
shale, and lignite partly intercalated with shallow-marine carbonates. More than
90% of exposed rocks in Java are Neogene-Quaternary in age. Marine conditions
prevailed during the Early-Middle Miocene with turbidite deposition in the north of
the island (Asikin, 1974). The Late Neogene strata constitute a regressive facies of
clastic material, which presumably resulted from the increased supply of
volcanogenic sediments derived from volcanoes in the south (Bolliger and de
Ruiter, 1976). The stratigraphy of the Quaternary sequence has been erected using
mammalia faunas, particularly fossil hominids such as Pithecanthropus erectus
(Early Pleistocene) and Homosoloensis (Late Pleistocene) (van Bemmelen, 1949).
However, subsequent work by Ninkovich and Burckle (1978) indicates that these
ages must be corrected to Late Pliocene-Early Pleistocene for the age of
Pithecanthropus erectus, and Middle-Late Pleistocene for the Homosoloensis.
2.4 Central Java
Central Java can be divided longitudinally into three physiographic regions
which are summarized below and in Figure 2-5.
1. The southern region or South Serayu Range (van Bemmelen, 1949)
which comprises the oldest rocks in Java, and contains mica schists and quartz
porphyry, dated at 117 Ma and 65 Ma respectively (Ketner et al., 1976), as
well as younger melange rocks and volcanic detritus of Oligocene to Miocene
age (Fig. 2-5, units 5 to 8).
2. The northern region or North Serayu Range which is composed of marine
volcanic detritus of Neogene age, and Pliocene to Pleistocene volcanic deposits
(Fig. 2-5, units 3 and 4). 13
3. The central region or Serayu Zone is characterized by a longitudinal depression.
It is filled by, and covered with, a series of Quaternary volcanic products including pyroclastic rocks, lavas and lahar deposits (Fig. 2-5, unit 2).
2.4.1 Magmatic evolution
As shown in Figure 2-3, locations of past and present subduction zones in
Indonesia show a regular temporal pattern, and become younger towards the Indian
Ocean. The distribution of related magmatic arcs, however, does not necessarily conform to this pattern.
The distribution of Tertiary and Quaternary magmatic arcs in Java indicates that volcanism shifted from south in the Tertiary to north in the Quaternary. This sweep of magmatic arcs includes three classic cycles of volcanism
(van Bemmelen, 1949). The fust cycle of volcanism or the general uplifting of the
Tertiary magmatic arc began in the Early Oligocene (Katili, 1973b). It originated in the south and is represented by calcalkaline rocks in the Southern Mountains
(Fig. 2-6). The second cycle of volcanism shifted farther to the north and comprises more alkaline lavas of Plio-Pleistocene age. It is marked by a series of volcanoes including Muria, Ungaran and Dieng (Figs. 2-5 and 2-6). The last cycle originated farther south and gave rise to several young active volcanoes such as
Sundoro, Sumbing, Merbabu and Merapi (Figs. 2-5 and 2-6). Thus, volcanism in
Central Java commenced in the south, swept northward and then migrated back southwards.
Two periods of voluminous explosive volcanism are recognized on the basis of data from drilling along the deep ocean floor south of Indonesia. The first occurred during the early-Late Miocene, and the second in the Late Pliocene and
Quaternary (Kennett and Thunell, 1975). These peaks of activity probably correlate with the peaks of the second and third volcanic cycles in Java as recognized by van
Bemmelen (1949). 14
2.4.2 Benioff Zone dip
In regions dominated by subduction zones the dip of the Benioff Zone normally decreases with time. This progressive decrease in dip has been attributed to the weight of the overriding continental plate which pushes the subduction zone oceanwards (Coney and Reynolds, 1977). Other factors such as the the rate of convergence at the subduction zone (Luyendyk, 1970), the age of subducted crust, temperature and buoyancy of the aseismic ridge (Kelleher and McCann, 1976) also play a significance role in the variation of the Benioff Zone dip.
In Central Java the shifting pattern of volcanism from the Tertiary to
Quaternary can be explained by a progressive decrease in the angle of dip of the
Benioff Zone during this period (Katili, 1973b). Between the Quaternary and
Present, however, the change in dip of the Benioff Zone does not appear to have
been significant.
As has been noted in section 2.3.1, the subduction zone in Java begins to
dip steeply approximately 200 km away from the present trench at a point 100 km
below the surface. The more steeply dipping part of the Benioff Zone can be
extrapolated to the surface to define a reference point (RP; Fig. 2-7). The depth (h)
to the Benioff Zone and the distance (d) between the locus of volcanism and the
reference point can be formulated as:
depth (h) = distance (d) x tangent 0 ,
where 0 is the dip of the Benioff Zone.
The active Sumbing volcano lies along longitude 110° where the Benioff
Zone has a dip of 55° (Fig. 1-1; Yokoyama et al., 1970). Assuming that the
potassium content of volcanic rocks from Java correlates with the depth to the
Benioff Zone (e.g. Hatherton and Dickinson, 1969; Whitford et al., 1979a), the
present depth (h) beneath Sumbing volcano is 173 km (Hutchison, 1976). Based
on this depth and the dip of the Benioff Zone (55°) the reference point (RP) is
121 km south of Sumbing volcano. 15
The Tertiary magmatic arc is now represented by the Southern Mountains
(van Bemmelen, 1949) which have similar magmatic affinities to other volcanoes in
Central Java including Sumbing, Sundoro and Merapi (Whitford, 1975a). The
Southern Mountains are situated approximately 50 km south of Sumbing and because the subduction zone has migrated southward with time (Fig. 2-3), the maximum distance from the Tertiary magmatic arc to the reference point would be approximately 70 km. Based on a depth (h) of 156 km for the Tertiary subduction zone (calculated from Hutchison's equation and using K20 content from Whitford,
1975a) and this distance (d) of 70 km, the Tertiary Benioff Zone would have had a minimum dip of 65°. This angle is significantly larger than the present dip of 55°.
Ungaran volcano is located 370 km north of the Java Trench which equates to a position 144 km north of the Sumbing reference point. The depth to the
Quaternary subduction zone beneath Ungaran is approximately 197 km
(Hutchison, 1976) and the dip angle calculated from these data is 54° which is not significantly different from the dip angle at present (55°). Thus geochemical differences within the volcanic products from Ungaran cannot be attributed to changes in the dip of the Benioff Zone. Similarly, geochemical differences between volcanic rocks from Ungaran and other Quaternary and Recent volcanoes (e.g.
Sumbing, Merapi and Sundoro) cannot be explained by a change in dip of the
Benioff Zone.
2.4.3 Rate of convergence
Luyendyk (1970) suggested a model in which the angle of dip of the subducted slab depends only on the length of the subducted slab or the convergence rate. He based this model on the assumption that the slab sinks under acceleration due to gravity at a constant rate and he expressed the relationship between these parameters (Fig. 2-8a) as : 16
dip (0) = arc sin V2/V0, where Vz (5 cm/y) is equivalent to the sinking rate due to gravity, and V0 is the convergence rate.
Based on a dip angle of 65° (Section 2.4.2), the rate of convergence in
Central Java during the Tertiary was 5.49 cm/y (Fig. 2-8b) which is slightly lower than in the Quaternary. Within the Quaternary, the rate of convergence increased from an initial value of approximately 5.75 cm/y (Muria) up to a maximum of
6.2 cm/y (Ungaran) and then decrease to the present rate of 5.85 cm/y for Merapi.
2.5 Ungaran
The geological map and stratigraphy of Ungaran volcano (Fig. 2-9) is compiled from the data of several previous workers. Because radiometric data are not available, samples for this thesis were collected only from lavas which have clear stratigraphic relationships. Pyroclastic rocks were not collected as significant loss of fine vitric ash occurs during their eruption, transportation and deposition which results in significant changes in composition of the magma (cf. Cas and
Wright, 1987).
Information on the local stratigraphy and structure have been derived from van Bemmelen (1949), Thaden et al. (1975) and Muhardjo et al. (1984). Four informal stratigraphic units comprising Oldest Ungaran, Old Ungaran, Parasitic
Cones and Young Ungaran are recognized (Fig. 2-9) and the locations of samples used in this thesis are shown on Figure 2-10.
2.5.1 Oldest Ungaran
The evolution of Ungaran volcano is characterized by three stages of growth, separated by two episodes of collapse of the volcanic cones
(Fig. 2-11; Table 2-1). Van Bemmelen (1941) noted that volcanism commenced in the northern part of Central Java at the end of the Pliocene after uplift of the North
Serayu range. During the Early Pleistocene a breccia composed of mafic volcanic 17
rocks was deposited, at least partly from lahar flows to form the Middle Damar Bed
(van Bemmelen, 1941; Thaden et al., 1975). This deposit crops out at Candi Hill
(Fig. 2-9) and because it thins to the north van Bemmelen (1941) inferred that the source was to the south, i.e. Oldest Ungaran. Erosion of Oldest Ungaran during the Early-Middle Pleistocene produced conglomerate, tuffaceous sandstone, volcanic breccia and tuff of the Upper Damar Bed (van Bemmelen, 1941;
Table 2-1).
The growth of Oldest Ungaran ended with the collapse of the cone, and the remnants may be found on the northern slope of the younger cone (van Bemmelen,
1941; Thaden et al., 1975; Muhardjo et al., 1984). The remnants consist of five hills (Fig. 2-11), of which the most elevated G. Munding (540 m) has a relative relief of more than 100 m (G. is the abbreviation for gunung which means mount or hill). The others are G. Sari (425 m), G. Ampel (465 m), G. Mengger (470 m) and G. Jadi (513 m). Thaden et al. (1975) and Muhardjo et al. (1984) consider that these five hills are composed of Early-Middle Pleistocene deposits. Muhardjo et al.
(1984) have assigned all rocks from Oldest Ungaran to a unit termed the Munding lava (Fig. 2-9).
2.5.2 Old Ungaran
The second evolutionary stage occurred during the Middle Pleistocene, giving rise to the deposits of Old Ungaran on the remnants of Oldest Ungaran
(Table 2-1, Fig. 2-11). These deposits consist of basalts, basaltic andesites and andesites which unconformably overlie the Upper Damar Bed
(van Bemmelen, 1941, 1949; Thaden et al., 1975; Muhardjo, 1984). Erosion of these deposits produced the Notopuro Formation which consists of volcanic breccia and lahars with tuffaceous interbeds (van Bemmelen, 1941; Sanny, 1985).
According to van Bemmelen (1941) Old Ungaran had a short life span.
Approximately one billion tonnes of eruption products accumulated on a basement consisting mainly of Neogene marls and plastic clays. Hence, the whole mountain 18
was subjected to a steadily increasing internal gravitational strain and after surpassing a certain limit, the structure collapsed to form the Kaligesik, Gentong and Suroloyo blocks (Fig. 2-12). Thaden et al. (1975) noted that several small parasitic cones, including G. Turun and G. Kendalisodo, developed along the fault system which was produced during the collapse of Old Ungaran.
Whitford (1975a) collected nine samples from the Suroloyo block. These samples comprise four from in situ lava flows and five from loose boulders and correspond to the olivine-augite bearing basalt described by van Bemmelen (1941).
Muhardjo et al. (1984) divided the stratigraphy of Old Ungaran into three separate units, comprising the Suroloyo basaltic lava (oldest), the Wanondo lava and the Kebrok lava (Fig. 2-9). The last activity of Old Ungaran produced viscous lavas which formed the Sangku and Kemalon domes (samples 923 and 924;
Fig. 2-10).
2.5.3 Parasitic Cones
Between the development of Old and Young Ungaran, several local eruptions took place along aring fractur e and other faults to produce the Parasitic
Cones comprising G. Turun (348 m), G. Suwakul (372 m), G. Mergi (573 m),
G. Kendalisodo (802 m), G. Gugon (724 m) and G. Pertapaan (880 m). Thaden et al. (1975) did not mentioned a specific age for the Parasitic Cones whereas the detailed stratigraphic study of Muhardjo et al. (1984) confirmed that the products of
Young Ungaran conformably overlie these Parasitic Cones.
On the basis of detail structural analysis, van Bemmelen (1949) reconstructed the chronological sequence for faults on Ungaran (Fig. 2-12). His
analysis was supported by Muhardjo et al. (1984) who confirmed that the Parasitic
Cones decrease in age from southwest to northeast. According to them, magma rose to higher levels along these faults and was eventually erupted to form the
Parasitic Cones. 19
2.5.4 Young Ungaran
The last stage of activity at Ungaran volcano is marked by Young Ungaran which rises approximately 2050 m above sea level. It started to grow during the
Late Pleistocene-Early Holocene (Table 2-1) and was built inside the caldera produced by subsidence of the previous cone (Fig. 2-12). Most of the ejected materials spread inside the basin enclosed by fault scarps. This basin is asymmetric with NE-SW and NW-SE diameters of 16 km and 21 km respectively. Lahar breccias have passed through the fault scarp in the east and south. These breccias are composed of unsorted volcanic debris with angular boulders up to 5 m in diameter. Stream deposits on the lower slopes of Ungaran were formed by reworking of lahar deposits. In general, the lavas from Young Ungaran are thick, and more abundant near the summit where they mostly form lava domes.
Young Ungaran was a relatively active volcano during its life. On the basis of morphology, structure, air photo interpretation and lithostratigraphy,
Muhardjo et al. (1984) recognized thirteen mappable units (Fig. 2-9).
2.5.5 Dating and correlation
Because no radiometric data for rocks from Ungaran are available, age determinations are based on published micropalaeontological data magnetostratigraphy, radiometric dating and formation correlation for Eastern and
Central Java (Fig. 2-13).
Ninkovich and Burckle (1978) proposed a very useful correlation of
Quaternary sequences in Java. They compared the hominid faunas of Java with the well dated ones of the Olduvai Gorge, and they analysed the planktonic diatom assemblages from the marine intercalations in the lowermost hominid-bearing beds.
In addition, they dated the tektites lying on the erosional surface separating the
Kabuh Formation (equivalent with Upper Damar Bed) from the overlying
Notopuro Formation (Fig. 2-13, column IH). 20
On the basis of lithological and fossil correlation, van Bemmelen (1949) has noted that the Kalibeng Formation, Pucangan Formation and Kabuh Formation
(Fig. 2-14, column in) are equivalent to the Lower Damar Bed, Middle Damar Bed and Upper Damar Bed respectively (Fig. 2-13 column IV). In addition, he points out that in the Ungaran complex, the Upper Damar Bed and Notopuro Formation
(Fig. 2-13, column IV) are the deposits from the erosion of Oldest and Old
Ungaran (Fig. 2-13 column VI), while Young Ungaran is equivalent to the beginning of the Young Volcanism Formation of Central Java (Fig. 2-13, column
IV). Volcanism in Central Java continued to migrate to the south and at present is marked by the very active volcano, Merapi (Fig. 2-13, column VII).
2.6 Summary
The islands of the Indonesian Archipelago are developing in response to interaction between the southward-moving Eurasian Plate, the northward-moving
Indian-Australian Plate and the westward-moving Pacific Plate (Fig. 2-1). Two major magmatic arc systems, the Sunda Arc in the west and the Banda Arc in the east, developed due to the subduction of the Indian-Australian Plate beneath the
Eurasian Plate (Fig. 2-2). The evolving system of island arcs in the Sunda Arc has been associated with a series of subduction zones which have migrated with time in response to changes in the tectonic setting of the region (Fig. 2-3).
Java Island, as part of the Sunda Arc, shows geological and geophysical features typical of island arcs, and the recognizable plate tectonic elements can be traced from south to north perpendicular to the east-west trend of the island
(Fig. 2-4). In contrast to the subduction zones which show a regular temporal pattern becoming younger towards the ocean (Fig. 2-3), the location of magmatic arcs in Java shifted from the south in the Tertiary to north in the Quaternary
(Fig. 2-6). This suggests that the dip of the Benioff Zone during the Tertiary must have been steeper than during the Quaternary (Fig. 2-8). 21
Between the Oligocene and Pleistocene three cycles of volcanism are recognized in Java. Ungaran volcano forms part of the second cycle of volcanism and is characterized by three stages of growth, interrupted by two episodes of cone collapse (Fig. 2-11; Table 2-1). The products of Ungaran volcano can be grouped into four informal units comprising Oldest Ungaran, Old Ungaran, Parasitic Cones and Young Ungaran, and correlation with other units in Java indicates that Ungaran was active between the Late Pliocene and the Late Pleistocene (Fig. 2-13). 22 23
CHAPTER 3
PETROGRAPHY AND MINERAL CHEMISTRY
3.1 Introduction
Petrographic data for 57 samples were determined using routine petrographic techniques and chemical data for minerals from 28 selected samples were determined by electron microprobe analysis. Modal data and microprobe analyses of the principal phenocrysts and groundmass phases are listed in
Appendices B and C respectively.
Total Fe is reported as FeO in all microprobe analyses. The ferric iron content of clinopyroxene was estimated using the method of Papike et al. (1974).
Ferric iron content of Fe-Ti oxide was estimated according to the method of
Carmichael (1967) on the ulvospinel basis, and as recommended by Leake (1978), ferric iron in amphibole analyses was calculated using the method of Stout (1972) by varying the Fe2+/Fe3+ ratio.
3.2 Oldest Ungaran
3.2.1 Basalt
Petrographic data for basalt samples from Oldest Ungaran are summarized in
Table 3-1. All samples are dark grey to black in hand specimen and are porphyritic with a holocrystalline or hypocrystalline groundmass. Phenocrysts comprise between 35 and 45% by volume of the rocks and mainly consist of plagioclase, clinopyroxene and Fe-Ti oxide. Olivine (or its pseudomorph) is found only in sample 921 whereas amphibole occurs in samples 926 and 929. The phenocrysts may be grouped into aggregates to produce a glomeroporphyritic texture.
Plagioclase is the most abundant phenocrystic phase and occurs as subhedral to euhedral grains. The maximum dimension is 1.6 mm but grains normally range 24
between 0.4 and 0.8 mm in size. Other phenocrysts such as clinopyroxene range in size between 0.1 and 4.0 mm but most fall within the range of 0.1 to 1.6 mm, with an average diameter of 0.6 mm. Fe-Ti oxide usually occurs as subhedral grains less than 0.4 mm in diameter. The groundmass of holocrystalline samples is very
fine-grained, and has a pilotaxitic, orthophyric or intergranular texture. Primary
groundmass minerals comprise plagioclase, clinopyroxene and Fe-Ti oxide
together with accessory apatite, whereas olivine and amphibole are absent. A
hypocrystalline groundmass is developed only in sample 921 and the glass
composition is listed in Appendix C-7. Secondary minerals in the groundmass
comprise calcite, chlorite and sericite.
The majority of plagioclase phenocrysts are fresh, but some grains show
minor alteration to chlorite and calcite, and many grains contain inclusions which
produce a sieve-like texture. Some phenocrysts also show a weak flow foliation
and have rounded edges due to resorption. Carlsbad, albite, combined Carlsbad-
albite and rare pericline twinning occur with normal zoning. The largest within
grain variation is up to 18.3 mole percent An (Fig. 3-1). Compositionally the
phenocrysts range from calcic labradorite to calcic anorthite whereas the
groundmass grains range from calcic andesine to calcic bytownite (Table 3-2;
Fig. 3-1). Thus, phenocryst grains are generally richer in An than the coexisting
groundmass.
Non-pleochroic, pale green clinopyroxene occurs both as phenocrysts and in
the groundmass of basalt samples from Oldest Ungaran. The phenocrystic
clinopyroxene is euhedral to subhedral with simple and lamellar twinning.
Compositionally the phenocrysts range from diopside to salite whereas the
groundmass is diopside (Table 3-3; Fig. 3-2). Zoning within phenocrysts is
minimal and the largest within grain variation is from W047 1^41 sFsn 3 to
Wo50.5En43.7Fs5.8- 25
Fe-Ti oxide occurs as phenocrysts and in the groundmass. Phenocryst grains are lower in ulvospinel and Ti02, but higher in Al203 than the coexisting groundmass grains (Table 3-4).
Amphibole occurs as euhedral to subhedral grains. All grains are strongly pleochroic (X = pale green-yellow, Y = green, Z = brownish green) and a few grains show zoning and sector twinning. Alteration to calcite and chlorite occurs in some grains. Rims of fine-grained magnetite (i.e. opacite) are common on most grains. Chemical data for amphibole in basalts from Oldest Ungaran are listed in
Table 3-5 and the phase is classified as ferroan pargasite (Fig. 3-3).
Olivine occurs as subhedral colourless grains with a rounded, resorbed rim and minor alteration along some transverse fractures. Representative microprobe analyses of olivine are listed in Table 3-6 and indicate that the grains are normally zoned from relatively Mg-rich cores (Fo68) to relatively Fe-rich rims (Fo59)
(Fig. 3-4).
3.2.2 Andesite
The andesite of Oldest Ungaran is grey in colour, inequigranular and porphyritic with phenocrysts of plagioclase, clinopyroxene, Fe-Ti oxide, amphibole, and mica set in a holocrystalline groundmass (Table 3-7). The phenocrysts range from 0.2 to 3.2 mm in length but most grains are between 0.5 and 1.2 mm long. The groundmass which shows a flow foliation, consists of plagioclase, clinopyroxene, Fe-Ti oxide and amphibole with intergranular or orthophyric textures.
Euhedral to subhedral plagioclase grains are the main phenocrystic phase and some grains have corroded, rounded edges, and exhibit a sieve-like texture with inclusions of clinopyroxene, Fe-Ti oxide and rarely amphibole. Phenocrysts have both normal and reverse zoning and Carlsbad and pericline twinning are common. Compositionally, both the phenocrysts and groundmass plagioclase are similar (Table 3-8; Fig. 3-5). 26
The phenocrystic and groundmass clinopyroxene grains of the Oldest
Ungaran andesite are pale green, non-pleochroic diopside. The phenocrystic
clinopyroxene is euhedral to subhedral and has simple and lamellar twinning.
Zoning within phenocrysts is minimal and coexisting phenocrysts and groundmass
grains have similar compositions (Table 3-9; Fig. 3-6).
Equant, euhedral to anhedral grains of Fe-Ti oxide occur both as
phenocrysts and in the groundmass. The compositions of phenocrystic and
groundmass Fe-Ti oxide are summarized in Table 3-10.
Amphibole is the most voluminous phenocrystic phase after plagioclase and
occurs as euhedral to subhedral grains. All amphibole grains are strongly
pleochroic from olive green (X) to brown (Y) and dark brown (Z). Analytical data
indicate that the amphibole is magnesian hastingsitic and magnesio-hastingsitic
hornblende (Table 3-11; Fig. 3-7).
Strongly pleochroic mica (X = light brown; Y = brown; Z = dark brown) is
a minor phenocrystic phase. Most grains arefresh bu t a few are rimmed by opacite.
Representative mica analyses are shown in Table 3-12 and Figure 3-8.
3.3 Old Ungaran
3.3.1 Basalt
Hand specimens of the Old Ungaran basalt are grey to black in colour,
holocrystalline and porphyritic. A glomeroporphyritic texture occurs in some
specimens. Plagioclase, clinopyroxene, Fe-Ti oxide and olivine occur as
phenocrysts in all samples whereas amphibole phenocrysts occur only in sample
822 (Table 3-13). The very fine-grained groundmass phases comprise feldspar,
clinopyroxene, Fe-Ti oxide and accessory apatite. Orthophyric, pilotaxitic or
intergranular textures are developed in the groundmass.
Phenocrysts of plagioclase occur as subhedral to euhedral prisms up to
1.6 mm long but have an average length of 0.4 mm. The grains are generally fresh
but some grains show alteration to chlorite and calcite. Albite, Carlsbad, combined 27
Carlsbad-albite and rare pericline twins occur. The plagioclase phenocrysts range from An60A to An94 6 in composition (Table 3-14) but most grains are between
An70 and Anso (Fig. 3-9). Plagioclase phenocrysts are normally zoned and the zoned grains have a compositional range from a few mole percent up to 31.5 mole percent anorthite. On average, the phenocrysts arericher in An than the coexisting groundmass grains (Table 3-14).
The clinopyroxene phenocrysts in Old Ungaran basalts are colourless to slightly greenish, euhedral to subhedral grains with simple and multiple twinning, and exhibit well developed cleavage. The groundmass grains occur as equant grains and are untwinned. Chemical data, which are summarized in Table 3-15 and
Figure 3-10, indicate that the clinopyroxene phenocrysts have only minor compositional zoning and between grain variation. The groundmass clinopyroxene is diopside, whereas the phenocrysts are mosdy salite 0?ig. 3-10).
Euhedral to anhedral granules of Fe-Ti oxide occur as phenocrysts and in the groundmass. The phenocrysts and coexisting groundmass grains are very similar in composition (Table 3-16).
Strongly pleochroic amphibole (X = fawn; Y = brown; Z = dark brown) occurs as subhedral to euhedral grains, and most are rimmed by opacite.
Representative chemical analyses are listed in Table 3-17 and indicate that the amphibole is magnesio-hastingsite (Fig. 3-11).
Olivine occurs in all basalt samples collected from Old Ungaran.
Phenocrysts occur as subhedral to slightly rounded grains and show transverse fractures and alteration to chlorite. Representative analyses of olivine indicate that the grains have normal zoning with a compositional range between Fo62 and Fo70
(Table 3-18; Fig. 3-12).
3.3.2 Basaltic andesite
The basaltic andesite of Old Ungaran is dark grey to black in hand specimen, holocrystalline, and is relatively fresh. All rocks are porphyritic and a 28
glomeroporphyritic texture is developed in some samples. Phenocrysts range from
35.7 to 42.5% by volume and include plagioclase, clinopyroxene and Fe-Ti oxide
(Table 3-19). Amphibole and olivine grains occur as accessory phases in some samples. Some specimens are vesicular or amygdaloidal with amygdales of chlorite or palagonite. Pilotaxitic, intergranular or interstitial textures occur in the groundmass (Table 3-19).
The most abundant phenocrystic phase is plagioclase which occurs as subhedral to euhedral grains ranging from 0.2 to 2.0 mm in length, but most plagioclase grains are between 0.4 and 0.6 mm long. Most of the plagioclase grains are fresh although a few grains exhibit minor alteration to chlorite and calcite, and some phenocrysts are aligned to define a flow foliation. Albite, Carlsbad-albite and pericline twinning occur in all samples and within grain variation is limited to
11 mole percent anorthite. Both normal and reverse zoning are present.
Compositionally, both phenocrystic plagioclase grains and the coexisting groundmass grains range from calcic labradorite to calcic bytownite (Table 3-20;
Fig. 3-13).
Clinopyroxene grains are colourless to pale green, weakly to non- pleochroic, and occur as euhedral to subhedral phenocrysts and as equant grains in the groundmass. Inclusions of Fe-Ti oxide are common and a subophitic texture is developed in some grains. The chemical composition of the single groundmass grain lies within the range of compositions shown by the phenocrysts (Table 3-21).
In the system Wo-En-Fs, the clinopyroxene grains in the basaltic andesite from Old
Ungaran plot as diopside and salite, and some grains are relatively enriched in Ca
(Fig. 3-14).
Equant, euhedral to anhedral Fe-Ti oxide grains occur as phenocrysts and in the groundmass. Chemical data for Fe-Ti oxide are summarized in Table 3-22 and indicate that the phenocrysts generally have lower contents of molecular ulvospinel than the coexisting groundmass grains. 29
Amphibole occurs as an accessory phase in the basaltic andesite of Old
Ungaran. Fresh grains show strong pleochroism from pale brown (X) to brown
(Y) and reddish brown (Z), and compositionally they are classified as magnesio- hastingsite (Table 3-23; Fig. 3-15).
The olivine phenocrysts are subhedral, colourless and occasionally are rimmed with iddingsite, or they are partially included in clinopyroxene.
Representative olivine microprobe analyses listed in Table 3-24 indicate that the cores contain a higher Mg/Mg+Fe2+ than the rims (Fig. 3-16).
3.3.3 Andesite
In hand specimen the andesite of Old Ungaran is dark grey in colour, porphyritic and holocrystalline. The phenocrysts range up to 2.0 mm in size and comprise plagioclase, clinopyroxene, amphibole and Fe-Ti oxide (Table 3-25). The groundmass is composed of very fine-grained plagioclase, clinopyroxene and
Fe-Ti oxide. Flow foliation in the groundmass is well developed and gabbroic inclusions occur in some samples.
Plagioclase phenocrysts are euhedral to subhedral with the grain size mostly between 0.4 and 0.8 mm, and exhibit Carlsbad, albite, Carlsbad-albite and pericline twinning with oscillatory zoning. Most grains are fresh and free of inclusions, and the within grain variation is minimal. Groundmass plagioclase is represented by microlitic feldspar with a pilotaxitic texture. Flow foliation is common. Both phenocrystic and groundmass phases are calcic labradorite
(Table 3-26; Fig. 3-17).
Non-pleochroic, slightly brownish to greenish, subhedral to euhedral grains of augite occur as phenocrysts and in the groundmass. Multiple and simple twinning occurs in phenocrysts but has not been detected in groundmass grains. A subophitic texture and inclusions of Fe-Ti oxide occur in a few phenocrysts.
Overall, the clinopyroxene of Old Ungaran shows only minor compositional 30
zoning and the composition of phenocrystic and coexisting groundmass grains are very similar (Table 3-27; Fig. 3-18). Fe-Ti oxide in the andesite of Old Ungaran occurs as phenocrysts and in the groundmass as euhedral to subhedral grains. Phenocrysts and groundmass grains are similar in composition (Table 3-28). Amphibole phenocrysts are largely replaced by Fe-Ti oxide and all phenocrystic grains have a reaction rim. Pleochroism is strong, from brownish
green (X) to brown (Y) and reddish brown (Z). Representative analyses of
amphibole are listed in Table 3-29 and indicate that the amphibole is
magnesio-hastingsite (Fig. 3-19).
3.4 Parasitic Cones
3.4.1 Basalt The basalt of the Parasitic Cones is a porphyritic, holocrystalline rock which
is dark grey in colour. Plagioclase is the dominant phase followed in decreasing
order of abundance by Fe-Ti oxide, clinopyroxene, amphibole and olivine
(Table 3-30). Plagioclase phenocrysts range from 0.4 to 2.0 mm in length but are
normally between 0.4 and 0.6 mm long, whereas phenocrysts of clinopyroxene,
Fe-Ti oxide, amphibole, and rare chlorite pseudomorphs after olivine are
approximately equant with a maximum dimension less than 0.8 mm. Groundmass
grains are less than 0.2 mm across and consist of feldspar, clinopyroxene,
Fe-Ti oxide, chlorite, calcite and accessory apatite. Pilotaxitic and orthophyric
textures are present (Table 3-30).
Plagioclase occurs as subhedral to euhedral phenocrysts and has albite,
Carlsbad-albite and rare pericline twinning with normal zoning. Some phenocrystic
and groundmass grains are altered and have been replaced by chlorite and hematite.
The compositional range of phenocryst grains is sodic labradorite to sodic
bytownite whereas the groundmass phase is labradorite (Table 3-31; Fig. 3-20). 3 1
The largest within grain variation is up to 15.4 mole percent anorthite
(Appendix C-l.1.3, sample 917, grain PI).
The clinopyroxene occurs both as phenocrysts and in the groundmass. Most phenocrysts are between 0.4 and 0.8 mm in length,-euhedral to subhedral, colourless to slightly green, non-pleochroic and most are rich in Ca (Table 3-32;
Fig. 3-21). The analyses of phenocrystic clinopyroxene from the Parasitic Cones have the highest wollastonite content found in basalts from Ungaran volcanic rocks.
Fe-Ti oxide in basalts of the Parasitic Cones form euhedral to anhedral grains which occur both as phenocrysts and as granules scattered throughout the groundmass. Analytical data are summarized in Table 3-33.
Strongly pleochroic amphibole (X = light brown; Y = brown; Z = dark to reddish brown) occurs as phenocrysts in the basalt of the Parasitic Cones.
Amphibole grains are often surrounded by a rim of granular Fe-Ti oxide or have been totally replaced by opacite. Chemically, they can be classified as magnesio-hastingsite and are unzoned (Table 3-34; Fig. 3-22).
Colourless olivine occurs as subhedral to anhedral grains with transverse fractures and rims of iddingsite. Chemically, the olivine of Parasitic Cones shows a relatively wide range of forsterite component (Table 3-35), and has both normal and reverse zoning (Fig. 3-23).
3.4.2 Basaltic andesite
Five samples have been selected from this group and the petrographic data are summarized in Table 3-36. They are all dark grey in hand specimen and have a holocrystalline groundmass. Plagioclase, clinopyroxene, and Fe-Ti oxide occur as the primary minerals in all specimens whereas olivine (or its pseudomorph) and amphibole occur in only two samples. Plagioclase phenocrysts range from 0.2 to
2.0 mm in length but are normally between 0.4 and 0.6 mm long. Other phenocrystic grains are as large as 3.0 mm but mostly are approximately equant 32
grains with a maximum dimension of between 0.4 to 0.8 mm. The groundmass grains may reach up to 0.1 mm in diameter and pilotaxitic, intergranular or interstitial textures are common.
Feldspar grains occur both as phenocrysts and in the groundmass. The phenocrysts are subhedral to euhedral grains which have Carlsbad, albite, pericline and combined Carlsbad-albite twinning. Normal, reverse and oscillatory zoning in the phenocrysts are common, whereas groundmass grains are untwinned, equant grains or microlitic laths. In general, the average composition of feldspar phenocrysts isricher i n anorthite than the coexisting groundmass plagioclase grains
(Table 3-37). The phenocryst rims have a similar range of compositions to groundmass grains (Fig. 3-24). Reverse and oscillatory zoning show compositional differences up to 26.2 and 27.6 mole percent anorthite, respectively.
In some samples K-feldspar occurs as thin rims on plagioclase phenocrysts
(e.g. sample 425). A few grains of microlitic feldspar have a compositional range ofOr296toOr6L3(Fig. 3-24).
Colourless to pale green, non pleochroic clinopyroxene occurs as
phenocrysts and in the groundmass as euhedral to subhedral grains. The
phenocrysts have simple and multiple twinning and are best classified as diopside
and salite (Table 3-38; Fig 3-25). Zoning within phenocrysts is minimal and
sample 425 exhibits the largest within grain variation from Wo4g 2En44 9Fsg 9 to
Wo50.6En43.3Fs6.0- Groundmass grains exhibit a more restricted compositional
range than the coexisting phenocrysts, and on average they have lower wollastonite
and higher ferrosilite contents than the phenocrysts (Table 3-38; Fig. 3-25).
Euhedral to anhedral equant grains of Fe-Ti oxide occur as phenocrysts and
in the groundmass. Representative microprobe analyses of phenocrystic and
groundmass grains are listed in Table 3-39. The phenocrystic Fe-Ti oxide phases
contain higher concentrations of A1203, MgO and Fe203 but lower Ti02 and
molecular ulvospinel than the groundmass grains. 33
Representative analyses of amphibole are summarized in Table 3-40 and in
Figure 3-26. Amphibole occurs as euhedral to subhedral phenocrysts with strongly resorbed rims. Some grains are totally replaced by opacite or hematite. All amphibole grains in the basaltic andesite of the Parasitic Cones are strong pleochroic from brownish green (X) to brown (Y) and dark brown (Z) and some
grains are twinned.
Olivine occurs in basaltic andesite as large xenocrysts up to 12.0 mm in
diameter and the majority of grains are replaced by chlorite. Compositionally, they represent the most Mg-rich (F089) olivine found in Ungaran lavas (Table 3-41).
Variation within the grain is minimal (Fig. 3-27).
3.4.3 Andesite
Petrographic data for andesite samples from the Parasitic Cones are
summarized in Table 3-42. In hand specimen the andesites are dark grey to black in
colour and microscopically they are holocrystalline porphyritic rocks. Phenocrysts
constitute up to 45% by volume of the rocks and consist of plagioclase,
clinopyroxene, Fe-Ti oxide, amphibole and mica. Plagioclase phenocrysts range
from 0.2 to 4.0 mm in length but are normally between 0.4 and 0.8 mm in size,
whereas other phenocrysts such as clinopyroxene, Fe-Ti oxide, amphibole and
mica are approximately equant with a diameter of 0.2 to 0.5 mm. The groundmass
is very fine-grained (0.01-0.1 mm). It consists of feldspar, clinopyroxene, Fe-Ti
oxide and rarely amphibole and mica with intergranular, orthophyric, intersertal or pilotaxitic textures.
Plagioclase phenocrysts occur as subhedral to euhedral prisms with abundant Carlsbad and Carlsbad-albite twinning and rare twinning according to the pericline and albite laws. Some phenocrystic grains show ragged edges resulting from resorption. A variety of zoning types occurs in these rocks. The largest zoned grain has oscillatory zoning with a compositional difference between core and rim up to 31.7 mole percent anorthite (Appendix C-l.3.3, sample 429, grain PI). 34
Chemical data for phenocrystic and groundmass grains are shown in Table 3-43
and Figure 3-28. Groundmass feldspars occur as subhedral to euhedral microlitic
laths. Although normal zoning is commonly found in plagioclase in andesite from
the Parasitic Cones, the average composition of cores in these rocks is less calcic
than the rims (Table 3-44).
The clinopyroxene occurs as both phenocrysts and in the groundmass. Most
of the phenocrysts are subhedral to euhedral but some grains may have ragged
edges due to resorption. The phenocrysts are colourless to very pale brown, non-
pleochroic salite, and some grains are enriched in Ca (Table 3-45; Fig. 3-29).
Multiple twinning is more common than simple twinning. Within grain variation
for clinopyroxene phenocrysts ranges from W046 3En37 3FS154 to
Wo52.1En42.6Fs5.3-
Fe-Ti oxide in andesite of the Parasitic Cones occurs as euhedral to anhedral
phenocrysts and in the groundmass. Representative microprobe analyses listed in
Table 3-46 indicate that the groundmass Fe-Ti oxide has a very similar composition
to the coexisting phenocrysts.
Amphibole occurs as subhedral to anhedral grains and in many samples is
totally replaced by opacite or hematite. Fresh phenocrysts show well developed
cleavage and some grains are zoned or twinned with strong pleochroism
(X = light brown; Y = brown; Z = dark brown). Compositionally, they are best
classified as magnesio-hastingsite (Table 3-47; Fig. 3-30).
Mica in andesite of the Parasitic Cones occurs as a minor accessory phase
with euhedral to subhedral outlines. The grains are all strongly pleochroic from
pale brown (X) to dark brown (Y = Z), and are rimmed by Fe-Ti oxide granules.
Representative chemical data are listed in Table 3-48. 35
3.5 Young Ungaran
3.5.1 Basalt
Petrographic data for basalt samples from Young Ungaran are summarized in Table 3-49. All samples are dark grey in colour, inequigranular, and porphyritic with a holocrystalline or hypocrystalline groundmass. Glomeroporphyritic texture is present in some specimens. Based on their mode of occurrence, the basalts of
Young Ungaran can be divided into lava flows and lava domes. The main mineralogical difference between these two is the abundance of amphibole in the lava dome, whereas in the lava flow amphibole is absent. The phenocrysts of both lava flow and lava dome basalts comprise plagioclase, clinopyroxene, Fe-Ti oxide and olivine. The phenocrysts of the lava flow basalt are set in a microcrystalline groundmass. The groundmass of the lava dome basalt is mostiy holocrystalline, fine- to medium-grained with an orthophyric or intersertal texture and consists of plagioclase, clinopyroxene and Fe-Ti oxide.
The plagioclase phenocrysts of both lava flow and lava dome basalts have euhedral to subhedral outlines and range between 0.2 and 2.4 mm in length, but are mostly approximately 0.6 mm in size. Many of the plagioclase phenocrysts have sieve-like textures and a flow foliation defined by alignment of both phenocrystic and groundmass plagioclase is common. Albite and combined Carlsbad-albite twinning are the dominant twin types, while pericline twinning is rare. The composition of plagioclase phenocrysts ranges from calcic andesine to calcic bytownite whereas groundmass plagioclase grains range from An47 7 to An813
(Table 3-50; Fig. 3-31). K-feldspar occurs in the groundmass and has a composition of Or524 (sample 418, grain GM1, Appendix C-l.1.4). As reflected by the average composition of core and rim (Table 3-51), most of the plagioclase from lava domes is characterized by reverse zoning. Normal zoning is common in the plagioclase phenocrysts from lava flow basalts of Young Ungaran and compositionally (Table 3-51) they have a more restricted range of anorthite content 36
than the lava dome basalts (Table 3-52). On average, the cores of plagioclase in the lava flow basalts arericher in An content than those in the lava dome basalts.
The clinopyroxene of Young Ungaran basalts is pale green, non-pleochroic, euhedral to subhedral with well developed cleavage, and displays multiple and simple twinning. Chemical data, which are summarized in Table 3-53 and
Figure 3-32, indicate that the variation between grains is within the range
Wo45 7En38 9Fs15 4 to Wo52 0En42 4Fs5 6. Most of the phenocrysts are salite and some grains show relative enrichment of Ca (Fig. 3-32). The groundmass clinopyroxene is very similar in composition to the coexisting phenocrysts.
Compositionally, clinopyroxene phenocrysts from the lava flow basalts are generally richer in Ti02 and A1203 than clinopyroxene from lava dome basalts
(Table 3-54).
Equant, euhedral to anhedral Fe-Ti oxide grains occur as phenocrysts and as groundmass grains in both the lava dome and lava flow basalts. Limited analyses of grains indicate that Fe-Ti oxide from the lava flow basalts have considerably
higher contents of Ti02 and A1203 than grains in the lava dome basalts. In addition
the molecular ulvospinel content of Fe-Ti oxides in lava dome basalts is lower than
in lava flow basalts (Table 3-55).
The amphibole phenocrystic and groundmass grains of the Lava dome basalts
occur as euhedral to subhedral grains which are strongly pleochroic from pale
brown (X) to brown (Y = Z). Reaction rims are very rare and most amphiboles
display well-developed cleavage and sometimes form as an aggregate with
clinopyroxene. Representative microprobe analyses of amphibole are summarized
in Table 3-56 and Figure 3-33.
Olivine in Young Ungaran basalts occurs as colourless, subhedral to
anhedral grains and most show secondary alteration. Representative microprobe
analyses of olivine are listed in Table 3-57, and in general olivine from the lava
flow basalts is slightly lower in Mg compared with the olivine of lava dome basalts
(Fig. 3-34). 37
3.5.2 Basaltic andesite
Petrographic data for basaltic andesite samples from Young Ungaran are summarized in Table 3-58. All samples are grey or dark grey to black in colour, porphyritic and inequigranular. Plagioclase, clinopyroxene and Fe-Ti oxide occur as the primary minerals. Most specimens contain amphibole and in some specimens this mineral is the dominant phase after plagioclase. The lava flow samples have a holocrystalline texture with a fine-grained groundmass whereas the groundmass of the lava dome samples is characterized by a grain size between 0.2 and 0.4 mm and
an intersertal or intergranular texture.
Plagioclase phenocrysts occur as subhedral to euhedral grains which show
albite, Carlsbad, Carlsbad-albite and pericline twins. The compositional range of phenocrysts is between An43 9 and An-753 (Table 3-59; Fig. 3-35). The grain size
ranges from 0.2 to 3.5 mm but most phenocrysts are between 0.6 and 1.2 mm in
size. The phenocrysts are relatively fresh with only minor alteration to calcite and
chlorite. Normal zoning occurs in only one grain (sample 827, grain PI,
Appendix C-1.2.4) while reverse zoning occurs in all specimens. The groundmass
composition, on average, has a higher An content than the coexisting phenocrysts
(Table 3-59). K-feldspar in the groundmass has a composition of Or6g 5
(Appendix C-1.2.4, sample 827, grain GM2; Fig. 3-35).
Phenocrystic clinopyroxene grains of the basaltic andesite have a slight pale
greenish or very pale brown tint, and are euhedral to subhedral, non-pleochroic and
show simple and multiple twinning. Some grains contain inclusions of
Fe-Ti oxide. Variation between, and within, grains is minimal and most of the
phenocrysts are salite. The groundmass clinopyroxene is untwinned and chemical
analyses of phenocrystic and groundmass grains are shown in Table 3-60 and
Figure 3-36.
Fe-Ti oxide occurs as euhedral to anhedral phenocrysts and as grains
scattered throughout the groundmass. Chemical data for Fe-Ti oxides are listed in
Table 3-61. 38
Strongly pleochroic amphibole (X = pale brown; Y = Z = brown) occurs as phenocrysts and exhibits subhedral to euhedral grain shapes with well developed cleavage. These phenocrysts are surrounded by opacite rims and based on chemical data the amphibole is best classified as magnesio-hastingsite (Table 3-62;
Fig. 3-37).
3.5.3 Andesite The andesite of Young Ungaran is dark grey in colour and porphyritic with a
holocrystalline groundmass. Phenocrysts comprise plagioclase, clinopyroxene,
Fe-Ti oxide, amphibole and mica (Table 3-63). Plagioclase is the dominant
phenocrystic phase followed by amphibole. In general, the phenocrysts are fresh
and alteration is minimal. Phenocrystic phases usually have grain sizes between
0.4 and 1.2 mm but a few plagioclase, clinopyroxene and amphibole grains are up
to 3.2 mm long. The groundmass has a pilotaxitic, orthophyric or intersertal
texture.
Plagioclase phenocrysts occur as subhedral to euhedral grains and generally
show Carlsbad twinning. Albite, combined Carlsbad-albite and pericline twinning
also occur although in subordinate amounts compared with Carlsbad twinning. On
average, the phenocrystic plagioclase is lower in anorthite content than the
coexisting groundmass plagioclase (Table 3-64). Although some phenocrystic
grains show reverse zoning with a variation of up to 23.3 mole percent An
(Appendix C-l.3.4, sample 320, grain P3), normal zoning is the dominant type of
zoning as shown by the higher average An content in phenocryst cores
(Table 3-65). All feldspar compositions are shown in Figure 3-38.
Euhedral to subhedral prisms of very pale green or very pale brown, non-
pleochroic salite and diopside occur as phenocrysts (Fig. 3-39). Unlike the
phenocrysts, simple and multiple twinning does not occur in the groundmass.
Clinopyroxene phenocrysts are very similar in composition to coexisting
groundmass grains (Table 3-66; Fig. 3-39). 39
Euhedral to anhedral, equant grains of Fe-Ti oxide occur in the groundmass and as phenocrysts. Compositionally, the phenocrysts arericher in Al203, MgO, and ulvospinel than grains in the groundmass (Table 3-67).
Amphibole occurs as euhedral to subhedral grains and all are pleochroic from pale brown (X) to brown (Y) and reddish brown (Z). In general the amphibole grains exhibit good cleavage and reaction rims occur on some grains.
Representative chemical analyses of amphibole are listed in Table 3-68. They are best classified as magnesio-hastingsite, magnesian-hastingsite, magnesio- hastingsitic hornblende and magnesian hastingsitic hornblende (Fig. 3-40).
Biotite is found as subhedral to euhedral grains which are strongly pleochroic (X = greenish brown; Y = Z = dark brown). The mineral occurs as an accessory phase and has a motded appearance, but many grains have been totally replaced by Fe-Ti oxide. Representative chemical data for mica are shown in
Table 3-69 and Figure 3-41.
3.6 Summary and discussion
In general, rocks from Ungaran volcano have strong similarities in mineralogy and texture. In hand specimen they are dark grey to black, and are porphyritic with either a holocrystalline or hypocrystalline groundmass.
Phenocrysts comprise 35% to 66% by volume of the rocks (Appendix B), and consist of plagioclase, clinopyroxene, Fe-Ti oxide and amphibole. Mica is a subordinate phase in basaltic andesite and andesite whereas olivine occurs in some samples of basalt and basaltic andesite. Plagioclase and clinopyroxene are the dominant phenocrystic phases. In some specimens, plagioclase comprises up to
33% by volume of the rock (Appendix B, sample 427). Most phenocrysts show little or no alteration with only minor replacement by chlorite and calcite. In holocrystalline samples, the phenocrysts are set in a fine-grained groundmass of either microlitic or granular feldspar, clinopyroxene and Fe-Ti oxide with pilotaxitic, orthophyric, interstitial or intergranular textures. Small gabbroic 40
inclusions consisting of granular aggregates of the phenocrystic phases are common, and a flow foliation is defined by parallel alignment of elongate phenocrystic and groundmass grains. In overall terms, the Ungaran lavas comprise a suite of fresh and well crystallized volcanic rocks with a high phenocryst content.
The average total phenocryst content of each rock type is very similar
(approximately 40%; Table 3-70) but the proportion of each phase differs. In particular, the volume of phenocrystic clinopyroxene and Fe-Ti oxide decreases in the series basalt to basaltic andesite to andesite, and the highest contents of amphibole and mica occur in andesite,
3.6.1 Plagioclase
Plagioclase is the most abundant phenocrystic phase in all Ungaran lavas
and occurs as subhedral to euhedral grains which range in size up to 4.5 mm
across. In some samples plagioclase phenocrysts are grouped into aggregates
producing a glomeroporphyritic texture. Most of the phenocrysts contain inclusions
which produce a sieve-like texture. Oscillatory, reverse and normal zoning are
common with the variation in composition ranging from only a few mole percent
anorthite up to a maximum of 46 percent (sample 320, grain PI,
Appendix C-l.1.4). Many grains are twinned according to the Carlsbad, albite,
Carlsbad-albite, or pericline laws and some phenocrysts are rimmed by K-feldspar.
The plagioclase phenocrysts in basalt lavas have a smaller compositional
range (Table 3-71; Fig. 3-42) than grains in basaltic-andesites (Table 3-72;
Fig. 3-43) and andesites (Table 3-73; Fig. 3-44). The compositions of phenocryst
rims and coexisting groundmass phases in each rock type are similar (Figs. 3-42 to
3-44), but in general the groundmass grains appear to have a more restricted range
in composition than the phenocryst rims. With increasing Si02 the average
chemical compositions of plagioclase phenocrysts and groundmass grains becomes
more sodic (Tables 3-71 to 3-73). 41
The range of compositions for cores of plagioclase phenocrysts in each rock type is similar (Fig. 3-45) but the andesites appear to contain two distinct compositional populations, one very calcic (> Ango) and the other less calcic
(< An55). The more calcic group may have resulted from accumulation of plagioclase.
Plagioclase phenocrysts in basalts become less calcic with increasing age
(Table 3-74). Similar patterns are also displayed by basaltic andesite and andesite samples (Tables 3-75 and 3-76). This may indicate that in general the plagioclase from Oldest Ungaran crystallized from a relatively less saturated and less alkaline magma compared to Old Ungaran, Parasitic Cones and Young Ungaran. However, detailed inspection of Figure 3-46 indicates that the composition of cores of feldspar phenocrysts in basaltic rocks from Young Ungaran and the cores of feldspar phenocrysts in basaltic andesites from Parasitic Cones show a wide range of compositions. The simplest explanation for this wide range of compositions is that basaltic rocks from Young Ungaran and basaltic andesite rocks from Parasitic
Cones may have resulted from some fractionation and accumulation of plagioclase.
The most significant differences in the compositions of plagioclase phenocrysts are shown in basaltic andesites from Old Ungaran, Parasitic Cones and Young Ungaran (Table 3-77). Plagioclase phenocrysts in basaltic andesites from Old and Young Ungaran are dominated by only one type of zoning with a small range of An contents and a bytownite or labradorite core (Figs. 3-13 and
3-35). In contrast, plagioclase phenocrysts in rocks from the Parasitic Cones are dominated by normal, reverse and oscillatory zoning. These phenocrysts have a wide range of An contents (Fig. 3-24), and the core compositions are dominated by bytownite to labradorite. These features indicate that plagioclase phenocrysts in basaltic andesites from the Parasitic Cones had a more complex crystallisation history than the corresponding phase in rocks from Old and Young Ungaran.
Zoning in plagioclase is indicative of failure of the mineral to attain equilibrium with the surrounding liquid and is normally attributed to change in 42
temperature and pressure either within the magma chamber or during ascent from the chamber to the vent (e.g. McBirney, 1979). Coexisting normal, reverse and oscillatory zoning is commonly regarded as being indicative of magma mixing
(Lung et al., 1982). The presence of coexisting normal, reverse and oscillatory
zoning in basaltic andesite from Parasitic Cones may be indicative of magma
mixing in the magma reservoir beneath Ungaran.
3.6.2 Pyroxene
Ca-rich pyroxene is the only pyroxene in lavas from Ungaran. This phase
occurs as subhedral to euhedral, colourless to greenish grains which exhibit weak
sector zoning, and range from 0.2 to 4.0 mm in diameter. Clinopyroxene occurs
both as phenocrysts and in the groundmass, and displays simple and multiple
twinning.
The composition of the clinopyroxene phenocrysts ranges from
Wo43 2En45 5Fsn 3 to Wo56 2En3g2Fs79 (Fig. 3-47; Tables 3-78 to 3-80).
Groundmass compositions are similar for all rock types but the clinopyroxene in
andesites (Table 3-80) is more restricted in composition than this phase in basalts
and basaltic andesites (Tables 3-78 and 3-79). Plots of clinopyroxene compositions
shown in Figure 3-47 indicate that Ca-enrichment decreases from basalt and
basaltic andesite to andesite.
The clinopyroxene phenocrysts in basalt samples (Table 3-78) are more
aluminous and Ti-rich compared with clinopyroxenes from basaltic andesites and
andesites (Tables 3-79 and 3-80; Fig. 3-48). Core and rim compositions are similar
for the three rock types but the mean compositions show a slight decrease in Al and
Ti and increase in Si from the core to the rim (Tables 3-81 to 3-83). In addition, the
mean content of Ti02 in diopside is higher than in either salite or augite
(Table 3-84; Fig. 3-48). According to Le Bas (1962) increased Al in Ca-rich
clinopyroxene is due to decreased silica activity in the magma, whereas the high Al
concentration in the Z site is responsible for the increase in Ti in the pyroxene 43
structure (e.g. Verhoogen, 1962). On the basis of this line of reasoning, the clinopyroxene phenocrysts in basalts (Table 3-78) crystallized from a relatively less saturated liquid than the clinopyroxene phenocrysts in basaltic andesites and andesites (Tables 3-79 and 3-80; Fig. 3-49). Furthermore, the cores of phenocrysts in each rock type (Tables 3-81 to 3-83) also crystallized from a relatively less saturated liquid than the rims. Similarly, the diopside phenocrysts probably crystallized from a relatively less saturated liquid than either salite or augite
(Table 3-84). This suggestion is supported also by modal data for clinopyroxene.
The lower mean modal content of clinopyroxene in andesite compared to that in basaltic andesite and basalt (Table 3-70; Fig. 3-50) is likely to be caused by the low aAl content and higher degree of silica activity in the magma reservoir.
Al^ also has simple linear relationships at the 99.9% confidence level with
Aivi, TJ4+ an^ Fe3+ (Fig. 3-51) and according to Marcellot et al. (1983) the slopes of these lines can be used to estimate the relative role of the principal theoretical
3+ IV pyroxene end-members, Fe Al Si06 and Al^Al^SiOg. The equations for the
IV 3+ rv regression lines (Fig. 3-51) indicate that the overall A1 contents of Fe Al Si06 and Al^Al^SiOg are 58.1% and 12.1% respectively. The slopes of the regression lines for the distribution of A1IV versus A1VI indicate that the A1IV content of
VI IV Al Al Si06 decreases from 15% through 12.9% to 11.1% in the series basalt- basaltic andesite-andesite (Fig. 3-52). These data indicate that the changes in clinopyroxene compositions in this series may be attributed to decreasing pressure because the Al^/Al^ ratio decreases with increasing pressure (e.g. Wass, 1979).
The relationship between phenocrystic clinopyroxene composition and time is summarized in Tables 3-85 to 3-87. In general Ti02 and Al203 decrease through time except for basalts and andesites from the Parasitic Cones which are anomalously high. The decrease of Ti02 and Al203 indicates that with increasing time the silica activity in the magma beneath Ungaran also increased (cf. Le Bas,
1962). 44
3.6.3 Fe-Ti Oxide
Fe-Ti oxide is common in all samples in the groundmass, as phenocrysts, and as inclusions in, and reaction rim products of, amphibole. The phenocrysts occur as anhedral to euhedral grains which are commonly associated with clinopyroxene. In some instances grain edges are rounded, which may indicate some resorption. In general the Fe-Ti oxide phenocrysts are relatively Ti-poor
(< Usp50) and are classified as magnetite. The absence of ilmenite and low contents of ulvospinel are typical of many island arc lavas and may be correlated with their
Ti02-depleted character, as suggested by Lowder and Carmichael (1970) and
Ewart (1976).
Compared with the Fe-Ti oxide phenocrysts of basalts (Table 3-88), the phenocrysts in basaltic andesites (Table 3-89) and andesites (Table 3-90) are lower in Ti02, A1203, MgO and ulvospinel. Cr203 is consistently low, generally below the detection limit and never exceeding 0.24%, which reflects the very low level of
Cr present in the magma.
The modal percent of Fe-Ti oxide phenocrysts, as well as clinopyroxene, decrease in the series basalt-basaltic andesite-andesite (Table 3-70) and reflect the decreasing Ti02 content of the magma. In addition, Ti02 and MgO contents of
Fe-Ti oxide in Ungaran lavas decrease with time whereas FeO increases
(Fig. 3-53). This may indicate that with increasing time the magma composition
beneath Ungaran becomes less magnesian and Fe becomes dominant over Ti.
3.6.4 Amphibole
In general the amphiboles are magnesian-hastingsite with strong greenish to reddish brown pleochroism. These amphiboles occur as large crystals up to
4.0 mm in diameter and most are characterized by reaction rims of opacite up to 0.2 mm thick. In many instances amphiboles from Ungaran have totally reacted to a granular aggregate of Fe-Ti oxides known as "black amphibole". The aggregates result from amphibole decomposition (Stewart, 1975) and are easily recognized on 45
the basis of their external morphology and fine-grained granular texture. Other authors have noted that hydroxy hornblende decomposition occurs under conditions of rapid cooling at low pressure (e.g. Kuno, 1950; Rittmann, 1973) and that they should be generated during eruption (e.g. Luhr and Carmichael, 1980) where fo2/fH2 is relatively increased (e.g. Garcia and Jacobson, 1979).
Various methods for estimating the ferric iron content of amphiboles have been discussed by Robinson et al. (1982). The lower limit is given by calculating all Fe as FeO whereas the upper limit is based on the assumption that all Fe is
Fe203. The method involving 13 cations (excluding Ca, Na and K) is commonly used for calcic amphibole and is favoured for use in rocks from orogenic areas.
The numbers of ions calculated on the basis of 23 oxygen atoms are listed in Tables
3-91 to 3-93 and using the classification of Leake (1978), these amphiboles are calcic with (Ca+Na)B >1.34 and NaB < 0.67.
Amphiboles in Ungaran are characterized by low numbers of Ti
(0.18-0.49), Si (5.27-6.35) and Al^ (< 0.54) ions and an increase in the average mean of K ions in the series basalt to basaltic andesite to andesite (Tables 3-91 to
3-93). The low Si values are characteristic of island arc hornblendes (e.g. Jakes and White, 1972) whereas the low contents of A1VI indicate that the amphiboles formed at pH20 < 9 Kb (Allen and Boettcher, 1978). The value of (Na+K)A
> 0.50 is characteristic of high-K suites (e.g. Gill, 1981).
3.6.5 Mica
Mica occurs as a common euhedral to subhedral accessory phase, but some grains are bent and distorted. The size ranges from 0.2 to 1.2 mm with an average of 0.4 mm. The micas are strongly pleochroic (X = pale-brown; Y = Z = brown), and many grains are surrounded by a rim of granular Fe-Ti oxide. The phase occurs in basaltic andesites and andesites but is absent from basalts. Most of the samples analysed are classified as biotite. Chemical data for mica from Ungaran are plotted in Figure 3-54. 46
3.6.6 Olivine
Olivine usually occurs as subhedral, colourless grains with transverse
fractures. Some grains display zones of secondary alteration to chlorite and
iddingsite. A compositional range from F059 to Fo79 has been found in the olivine
grains. Zoning in most grains exhibits the normal pattern of Fe-enrichment towards
the rims of phenocrysts (Figs. 3-4, 3-12, 3-16, 3-23 and 3-34).
Roeder and Emslie (1970) determined that the partition of Fe2+ and Mg
between olivine and coexisting liquid is given by :
KD = (Fe/Mg)olivine/(Fe/Mg)liquid,
where Krj) is the distribution coefficient.
The experimental work of Roeder and Emslie (1970) has shown that for basaltic liquids at 1 Kb total pressure, the distribution coefficient (Kp) for the
Fe/Mg partition between olivine and coexisting basaltic liquids is 0.3. Nicholls (1974), however, suggested the value for Krj may be approximately 0.4 if fusion
occurred under high pressure hydrous conditions or lower temperatures
(e.g. 1000°C; Bender et al., 1978). In Java, the maximum depth to the Benioff
Zone beneath Ungaran is 197 km (Chapter 2) which is equivalent to a maximum
pressure of approximately 60 Kb. At this pressure, the KD would be 0.4 based on
the model proposed by Takahashi and Kushiro (1983) who found that the KD
increases with increasing pressures according to the relationship KD = 0.3 +
0.002P (where P is the pressure in Kb).
On the basis of the observed olivine composition and Roeder and Emslie's
equation, the Mg-number of the liquid in equilibrium with the olivine can be
calculated. Similarly, the Mg-number of the observed total-rock sample can be
calculated and the two Mg-numbers can be compared to determine whether the
olivine phenocrysts in Ungaran are in equilibrium with their host rocks. The
Mg-number of the whole-rock samples has been calculated assuming that FeO is
either 0.80 or 0.90 times total Fe as FeO and the results of these calculations using
KD value of both .3 and 0.4 are listed in Table 3-94 to 3-97. 47
The Mg-numbers of bulk rocks samples of basalts from Oldest Ungaran
(Table 3-94), lie above the range for liquids in equilibrium with the observed phenocrysts. The simplest and most probable explanation is that there was some accumulation of olivine phenocrysts.
The analysis of basalt sample 832 from Old Ungaran (Table 3-95) shows the
Mg-number of the rock lies within the range for liquids in equilibrium with the observed olivine phenocrysts. The simplest explanation is that the olivine grains were formed by near-liquidus crystallisation with no subsequent fractionation of crystals. In contrast, sample 826 has a higher Mg-number than values computed for liquid in equilibrium with the observed olivine (Table 3-95). The relatively high
Mg-number of this total-rock sample compared with the value for the enclosed olivine phenocrysts may be controlled by accumulation of the early-formed olivine which tends to raise the Mg-number of the total rocks. Most of the rocks from Old
Ungaran lavas, however, have Mg-numbers within the range of values for liquidus in equilibrium with the observed olivine phenocrysts.
Two different generations of olivine occur in basalts from the Parasitic
Cones (Table 3-96). The olivine grains in sample 917 are too Fe-rich, and the xenocryst in sample 428 is too Mg-rich, to represent the products of near-liquidus crystallisation. The host basalts from Young Ungaran, in general, have
Mg-numbers within the range of values for liquids in equilibrium with the corresponding olivine phenocrysts (Table 3-97). This suggests that these phenocrysts formed by near-liquidus crystallisation with little or no subsequent fractionation of crystals.
3.6.7 Order of crystallisation
The order of crystallisation for a set of comagmatic lavas has an important role in understanding the magma's behaviour beneath the volcano. The position of plagioclase in the sequence of crystallisation, for example, is a useful qualitative indicator of water saturation in the near surface environment because plagioclase 48
has a great sensitivity to water content in the magma. It is impossible to establish the sequence of crystallisation by only using classical methods of thin section study. For example, in a single thin section plagioclase contains inclusions of augite, and augite contains inclusions of plagioclase.
Based on modal analyses of thin sections, however, Wright and Okamura
(1977) demonstrated that total phenocryst content can be used as an accurate measure of isobaric cooling. Marsh (1981) expanded this idea and constructed the mode-crystallisation (M-C) diagram in order to determine the sequence of crystallisation and establish the relationship between crystallinity and temperature.
The M-C diagrams (Figs. 3-55 to 3-57) for Ungaran lavas show that the sequence of crystallisation is olivine, plagioclase, clinopyroxene, Fe-Ti oxide, amphibole and mica. Petrographic data indicate that Fe-Ti oxide is not abundant as inclusions in clinopyroxene phenocrysts and very rare in plagioclase. Hence, the
M-C diagram for the sequence plagioclase, clinopyroxene and Fe-Ti oxide may be reasonable in determining the sequence of crystallisation, which is necessary in order to establish the fractional crystallisation model. The appearance of Fe-Ti oxide after clinopyroxene may indicate that oxygen fugacity in Ungaran lavas is not significantly high, whereas the later appearance of amphibole and mica is controlled by decreasing temperature at low or moderate pressures (i.e. < 9 Kb; Allen and
Boettcher, 1978).
However, some discrepancies of the order of crystallisation occur in basaltic samples which may also have another sequence including plagioclase, clinopyroxene, Fe-Ti oxide, amphibole and olivine (Fig. 3-56), The different sequence of crystallisation in basalts demonstrates the difficulties in using this method for determination of the order of crystallisation. A possible explanation for this diversity is the imprecision of this method in locating the upper limit for small amounts of olivine. Small gains and losses of this phase, which are caused by fractionation and accumulation, will certainly affect the results significantly.
Another possibility is that the two different upper limit lines in the 49
olivine-groundmass plot (Fig. 3-55) may represent two different magma compositions.
3.6.8 Pressure and temperature of crystallisation
Many workers have suggested that the chemical composition of pyroxene can be used to determine its pressure and temperature of crystallisation. According to Thompson (1974) low pressure crystallisation of clinopyroxene is indicated by the relatively homogeneous distribution of Na in augite and salite. Velde and
Kushiro (1979) have noted that the crystallisation pressure in the host magma is reflected by the relative amounts of tetrahedrally and octahedrally coordinated aluminium in clinopyroxene. With increasing pressure, aluminium would substitute in the Ml site (octahedral) instead of the T site (tetrahedral), and as a consequence, the Al^/AP71 ratio would decrease (Wass, 1979). Furthermore, some statistical data for orogenic lavas (Ewart, 1976) show that the phenocryst paragenesis of basaltic or andesitic volcanic rocks from island arcs is generally interpreted as reflecting low pressure crystal fractionation.
The composition of most clinopyroxene phenocrysts from the Ungaran rocks (Fig. 3-58) lies below the low pressure field proposed by Aoki and Kushiro
(1968). Compared with the A1IV (0.05 to 0.17 atomic proportion) and A1VI
(0.01 to 0.06 atomic proportion) concentration in the New Hebrides island arc suite which crystallized at pressures up to 5 Kb (Marcellot et al., 1983), the Ungaran volcanic rocks have higher A1IV, slightly lower A1VI concentration and consequently a higher Al^/Al^ ratio which may indicate they crystallized at pressures less than
5 Kb. The amphiboles from Ungaran generally show a relatively low content of
A1VI which suggests that they formed at pressures less than 9 Kb (e.g. Allen and
Boettcher, 1978). In addition, the crust in the Ungaran region has a maximum thickness of approximately 25 km (Section 2.2) which equates to a maximum crystallisation pressure of approximately 9 Kb (cf. Foden, 1983). 50
Determination of the temperature of phase crystallisation is easier than pressure estimation. Buddington and Lindsley (1964) developed a model to determine the temperature and oxygen fugacity of formation based on coexisting magnetite and ilmenite. This model was refined by Powell and Powell (1977), but no such coexisting pairs exist in Ungaran rocks. The minimum temperature of clinopyroxene crystallisation, however, can be estimated from the graphical thermometer of Lindsley (1983).
Calculated temperatures derived from phenocryst rim compositions of clinopyroxene, which presumably record magmatic temperatures on eruption, show that the basalts have a relatively restricted range in temperature compared with basaltic andesites and andesites (Fig. 3-59). The average temperature calculated on the basis of clinopyroxene thermometry (Table 3-98) decreases from basalt to basaltic andesite whereas andesite has a higher average temperature than basaltic andesite. The average temperature for the cores of phenocrysts of basalts is higher compared with basaltic andesite and andesite. A similar situation is also shown for phenocryst rims with the exception that the rims of clinopyroxene in andesites indicate higher temperatures than basaltic andesites. The relatively high average temperature for andesite is mainly caused by the data for three grains which have a relatively high calculated temperature (Fig. 3-50). The clinopyroxene grain observed in this sample probably represents a cumulative phase.
Amphibole can also be used as geothermometer (Helz, 1979). Data for the calculation were taken from 48 amphibole-whole rock pairs, and the K/Na ratio of the melt was assumed to be the K/Na of the whole-rock sample. All temperature calculations were based on equation 5 of Helz (1979) and the results are 1154°C for basalts, 1120°C for basaltic andesite and 1115°C for andesite. These average temperatures are higher than the supposedly maximum thermal stability of amphibole in andesite melt (approximately 950°C; Gill, 1981). A temperature calculation using the Ti content of amphibole proposed by Otten (1984) yields more realistic results than the method of Helz (1979). Phenocryst rim compositions 5 1
show a more restricted range of temperatures (930 - 969°C) than phenocryst cores
(926 - 1012°C). On average, the phenocryst rims in basalt, basaltic andesite and andesite display a consistently lower temperature than the cores (Table 3-99).
Overall, the amphibole and clinopyroxene temperatures generally overlap and both are in the range expected for temperatures of magmatic crystallisation. 52 53
CHAPTER 4
TOTAL-ROCK GEOCHEMISTRY
4.1 Introduction
In the present study, 57 samples were analysed for major and trace elements
by X-ray fluorescence, atomic absorption and wet chemical methods. Rare earth
elements (REE), Sc, Co, V, Cr, Ba, Zn, Hf and Ta concentrations in 30 samples
were determined by instrumental neutron activation analysis, and strontium isotopic
ratios for 12 samples were measured on a single channel mass spectrometer. All
analytical methods are listed in Appendix A.
Major element results are expressed as weight percent of the oxide of the
element and have been recalculated to total 100% on a volatile-free basis. Trace
element data are expressed as parts per million and all analyses are reported as
analysed. REE contents are normalized to the chondrite values of Haskin et al.
(1968) and the Gd values are interpolated from the Sm to Yb join. Unless
otherwise indicated, discussion concerning the temporal distribution of trace
elements is limited to Rb, Sr, Zr, Pb, Th, Y and Nb because these elements were
determined for all samples.
Major and trace element analyses for Ungaran volcanic rocks and CIPW
norms are listed in Appendices D and E respectively.
4.2 Geochemical features and variation
Based on their Si02 contents (Fig. 1-2), the samples analysed and reported
here comprise 18 basalts, 22 basaltic andesites and 17 andesites. Most basalts are
shoshonitic whereas most basaltic andesites and all andesites fall within the high-K
calcalkaline field (Fig. 4-1). Harker variation diagrams for major elements are
shown in Figure 4-2. 54
On the basis of the eruptive history and the time of emplacement
(Chapter 2), the temporal variations in the geochemistry of Ungaran volcanic rocks are divided into two groups comprising short term variations and long term variations. Short term variations occur during a single cycle of volcanic activity
(or eruptive epoch; Fisher and Schminke, 1984) and for Ungaran volcano, four cycles comprising Oldest Ungaran, Old Ungaran, Parasitic Cones and Young
Ungaran are recognized. Long term variations occur over the life span of a volcano
(or eruptive period; Fisher and Schminke, 1984) and, hence, deal with the relationships between the short term cycles.
All analysed samples come from units with good stratigraphic control
(Section 2.5) but because the numerical age of Ungaran volcanic rocks is not
known, a constant numerical time interval has been assumed in order to construct
the diagrams illustrating temporal geochemical variations. Thus, the chemical
composition of the first flow (oldest) is plotted against number 1, the second flow
is plotted against number 2, the third flow against number 3 and continuing until
the last flow (youngest).
4.2.1 Oldest Ungaran
Representative chemical analyses are listed in Appendix D-l while the
major and trace element mean, standard deviation and range are listed in Tables 4-1
and 4-2. The plot of K20 against Si02 (Fig. 4-1) shows that all basalt samples (4)
from Oldest Ungaran are shoshonitic while the andesite falls within the high-K
calcalkaline field. With the exception of Si02, Na20 and K20, the basalts in
general have higher mean contents of major elements than the andesite (Tables 4-1
and 4-2). The Mg-numbers for basalts are relatively low (0.45 - 0.50) whereas the
Differentiation Index (D.I.) for the andesite is high at 58.7. All basalts are
oversaturated when the CIPW norms were calculated using the analysed
Fe203/FeO+Fe203 value, and most samples are saturated if an assumed ratio of
0.2 for Fe203/Fe0+Fe203 (Hughes and Hussey, 1976) is used (Fig. 4-3). 55
Within the rocks from Oldest Ungaran, Rb ranges between 51 and 103 ppm
and Sr ranges between 408 and 523 ppm (Tables 4-1 and 4-2). Some trace
elements have a relatively restricted range, for example Zr (105 to 165 ppm), Nb
(10 to 15 ppm) and Y (24 to 39 ppm). Th and Pb have minimum values of 6 and 14
ppm, and maximum values of 15 and 25 ppm respectively (Tables 4-1 and 4-2).
With the exception of Sr, Cr, V, Sc and Zn, the average content of all analysed
trace elements in the andesite is higher than the average value for the basalt samples
(Tables 4-1 and 4-2). The REE patterns for basalts and andesite of Oldest Ungaran
are very similar except that the andesite is more enriched in all REE except Eu
(Fig. 4-4). Both samples are moderately fractionated (LaN/YbN values of 5.6 and
8.8) with slight negative Eu anomalies (Eu/Eu* ratios of 0.82 and 0.91).
As shown in Appendix D-l, the 87Sr/86Sr ratio of the basalt (0.70508) is
slightly higher than the andesite (0.70497). This difference, however, is not
significant when the analytical uncertainty at the 95% confidence level is taken into
account (Appendix A) and the two rock types may be related by fractionation (Appendix 1-1).
Plots of the major and trace element contents versus time are shown in
Figures 4-5 and 4-6 respectively. Compared to other groups of Ungaran rocks, samples from Oldest Ungaran have the widest range of S-O2 values which increase
with time from 49.39 to 60.80%. Contents of K2O and Na20 also increase with
time whereas several other oxides including total FeO decrease. Rb, Pb, Zr, Th,
Nb and Y show a general increase with time whereas Sr is variable but tends to decrease.
Modal abundances of plagioclase, clinopyroxene and Fe-Ti oxide decrease with time (Fig. 4-7) and the modal mineralogy exhibits a well-defined correlation with total-rock chemistry (Table 4-3). The most significant correlations are those between: (a) modal plagioclase phenocrysts and total-rock A1203; (b) modal clinopyroxene phenocrysts and total-rock MgO, total FeO, Ti02 and CaO; and (c) modal Fe-Ti oxide phenocrysts and total-rock Al203« In the samples from Oldest 56
Ungaran the role of A1203 in plagioclase is reflected by the depletion of both AI2O3 and modal plagioclase with time (Figs. 4-5 and 4-7). The content of CaO also decreases with time but this oxide does not exhibit a significant correlation with the abundance of modal plagioclase (Table 4-3). In contrast, clinopyroxene shows a
strong correlation with both CaO and MgO, whereas Fe-Ti oxide shows a very
significant positive correlation with AI2O3 (Table 4-3).
4.2.2 Old Ungaran
Representative chemical analyses of samples from Old Ungaran are listed in
Appendix D-2 whereas the major and trace element mean, standard deviation and
range are listed in Tables 4-4 to 4-6. The 11 lava flows in this group comprise six
basalts, four basaltic andesites and one andesite. Five basalt samples are
shoshonites and most of the basaltic andesites samples (3) and andesite are high-K
calcalkaline Q7ig. 4-1). The average value for Ti02, total FeO, MgO, CaO, Na20 in
the basalts is higher than in the basaltic andesites and andesite. Mg-numbers for the
basalts are relatively low (0.40 to 0.50) and the D.I. ranges from 36.1 to 47.0
(Table 4-4). These basalts are Q-normative when the CIPW norm is computed
using the analysed Fe203/FeO+Fe203 ratio, and all are Ol-normative if an assumed
value of 0.2 is used for this ratio (Fig. 4-8).
The average values for Rb and Nb increase whereas Pb, Co and Zn
decrease from basalts through basaltic andesites to andesite. Contents of other
elements are variable but in general, Sr, Cr, V and Sc tend to decrease whereas Zr,
Th, Y, Co, Hf, Ba and Ta tend to increase with increasing silica content. The REE
patterns for seven samples (Fig. 4-9) are all enriched in light REE (LREE), and
show low to moderatefractionation wit h moderate to slight negative Eu anomalies
(Eu/Eu* = 0.86 to 0.95). Basalt sample 832 is the least fractionated rock with a
LaN/YbN ratio of 4.4, and it has much a lower LREE content (LaN = 54.2) than the
other basalts (LaN = 104.2 to 147.3). Basaltic andesite sample 820 is the most
fractionated sample from Old Ungaran with a LaN/YbN ratio of 16.9. Andesite 57
exhibits a similar REE pattern to most of the basalts and basaltic andesites from Old
Ungaran. The main difference is that the andesite has a higher heavy REE (HREE) concentration than the basalts and basaltic andesites (Fig. 4-9).
The 87Sr/86Sr ratio of the basalt is higher (0.70520) than andesite
(0.70477), whereas the basaltic andesite has the lowest ratio (0.70467). At the 95% confidence level for the analytical uncertainty (see Appendix A) the ratios for the basaltic andesite and andesite are indistinguishable but both are significandy lower than the value for the basalt These data indicate that the basalt cannot be related to either of the other rock types by simple fractionation processes. In contrast, the basaltic andesite and the andesite may be related by fractionation processes
(Appendix 1-2).
Temporal variations in major element contents, particularly Si02, Ti02 and
FeO, suggest that the products of Old Ungaran may be subdivided into three groups comprising units 1 to 4, units 5 to 8, and units 9 to 11 (Fig. 4-10). The least evolved rocks (lowest Si02 and highest MgO) occur in the second group whereas the most evolved rocks (highest Si02 and lowest MgO) occur in the third group. In addition, the most evolved rock (sample 924) is the youngest unit from
Old Ungaran.
The groups indicated by the temporal variations in major element contents are not entirely consistent with temporal variations in the trace element data
(Fig. 4-11). In particular, unit 5 (sample 826) which appears to fit into the second group on the basis of the major element data has trace element contents which suggest closer affinities with units in group one. Some within group variations are also inconsistent. For example, the Rb content decreases with time within group one, but increases in both groups two and three. The Sr content increases with time in both groups one and two but has no consistent trend in group three. Contents of
Zr and Th also consistently increase with time in groups two and three but the irregular variation shown by most trace elements may reflect complex processes in the petrogenesis of magmas for Old Ungaran. 58
Sample 832 (unit 6, Fig. 4-11) has the lowest values for Rb (40 ppm),
Sr (415 ppm), Zr (105 ppm), Th (2 ppm), Nb (8 ppm), a low value for Y (25 ppm)
and the highest value for Pb (31 ppm). In addition, this sample also contains the maximum content of Co (40 ppm), high contents of both V (256 ppm) and
Sc (20 ppm), and it has the minimum value for Ta (0.24 ppm) (Appendix D-2). In
contrast, sample 924 (unit 11, Fig. 4-11) has the highest content of Ta (0.60 ppm),
Rb (94 ppm), Zr (181 ppm) and Y (42 ppm), but has a low content of Co (26 ppm)
and the lowest values for V (143 ppm) and Sc (11 ppm) (Appendix D-2). On the
basis of these trace element contents sample 832 may represent the least fractionated
or most primitive rock and sample 924 depicts the most evolved rock within Old
Ungaran.
Temporal variations in modal contents of plagioclase, clinopyroxene and
Fe-Ti oxide do not follow any consistent trends within the groups identified on the
basis of the geochemical data 0?ig. 4-12). In contrast, temporal variations in olivine
content are more consistent and although showing relatively little variation in group
one, the modal content of this mineral decreases with time in both groups two and
three. The correlation matrix (Table 4-7) indicates that the modal mineralogy does
not correlate significantly with total-rock chemistry except for olivine which has a significant positive correlation with Ti02,tota^ FeO anc* Pb. The maximum modal
content of olivine and the minimum modal content of Fe-Ti oxide occurs in sample
832 (unit 6; Fig. 4-12) where Rb, Sr, Zr, Th and Nb reach the minimum value but
Pb content is at the maximum. In addition, this sample is also characterized by a
high content of plagioclase but a low content of modal clinopyroxene and total
phenocrysts. This relationship suggests that sample 832 may have crystallized from
a magma with a relatively high primary Pb and Ti02 content but a relatively low
content of Rb, Sr, Th and Nb. 59
4.2.3 Parasitic Cones
Chemical analyses of samples from Parasitic Cones are listed in Appendix
D-3 while the mean, standard deviation and range of compositions are summarized in Tables 4-8 to 4-10. Eleven samples were collected from this group and except for samples 917 and 202 which are shoshonites, all rocks of the Parasitic Cones are high-K calcalkaline in character (Fig. 4-1). Contents of all major elements except the alkalies decrease with increasing silica content. Si02 ranges from 57.32% to
49.04%; K20 has a greater range (2.26 to 3.25%) than Na20 (3.06 to 3.59%) and
Al203 is relatively high and variable (17.69% to 20.0%). The maximum
Mg-number for the basalt is relatively low at 0.51, whereas the D.I. for the andesite is high at 52.1. The only basalt in this group is Ne-normative when the CIPW norm is calculated irrespective of the use of either the analysed ratio or an assumed value of 0.2 for the Fe203/FeO+Fe203 ratio (Appendix E-3, sample 917).
The average contents of Rb, Zr, Nb, Hf and Ba increase whereas Y and V decrease with increasing silica contents (Tables 4-8 to 4-10). The average content of Ta in basalt is slightly higher than in the basaltic andesites but both are lower than in the andesite. The average contents of Sr, Cr, Sc, Co and Zn in basaltic andesites is higher whereas Pb is lower than in the basalt and andesites (Tables 4-8 to 4-10). Although the contents of Sc, Co, and Cr are erratic, they generally have low values. The basalt shows moderate fractionation of REE (Fig. 4-13) with a
LaN/YbN ratio of 6.4, and is enriched in LREE (LaN = 87.6). Basaltic andesites display similar patterns with LaN between 88.5 and 91.2 and LaN/YbN ratios between 7.8 and 8.3. Two samples of andesite display slightly different REE patterns. Sample 429 has a similar pattern to those of the basalt and basaltic andesites and it has a high LREE content (LaN = 93.3), whereas sample 919 has a relatively low content LREE (LaN = 56.7) and is slightly fractionated (LaN/YbN =
4.7). In general all samples have moderate negative Eu anomalies (Eu/Eu* ranges between 0.79 and 0.86), except sample 919 (Eu/Eu* = 1.08). This positive anomaly may indicate slight plagioclase accumulation. 60
As shown in Appendix D-3, the 87Sr/86Sr ratio for basalt and andesite are indistinguishable (0.70505 and 0.70497 respectively), while the basaltic andesite
(sample 425) has the highest value (0.70527) for samples from the Parasitic Cones.
These isotopic data indicate that derivation of the andesite from the basalt by fractionation is plausible (Appendix 1-3) but the basaltic andesite cannot be related to the other rock types by simple fractionation.
Temporal variations in the major element geochemistry of samples from the
Parasitic Cones are shown in Figure 4-14 and three groups are recognized comprising units 1 to 4, units 5 to 7 and units 8 to 11. On the basis of the MnO and
Na20 contents, however, unit 4 (sample 428) appears to have more affinity with
samples in the second group rather than the first group. Overall, sample 429
(unit 1) has the highest content of Si02, relatively low MgO, and lowest content of
CaO, total FeO and Ti02 (Appendix D-3). In contrast, sample 917 (unit 8) has the
lowest value for Si02 but the highest content of MgO, CaO, total FeO and Ti02. In
general, contents of MgO, CaO, total FeO and Ti02 tend to increase with increasing
time.
On the basis of trace element contents, the 11 samples from the Parasitic
Cones can be divided into three groups comprising samples from units 1 to 4, units
5 to 8 and units 9 to 11 (Fig. 4-15). The groups are not entirely consistent with
temporal variations in the major element data. Unit 8 (sample 424), in particular,
has trace element contents which suggest closer affinities with units in the second
group rather than in the third group. In the first group, Rb, Pb, Zr and Th decrease
with increasing time whereas Sr increases. The second group is characterized by a
general decrease in the contents of all trace elements. In the third group, Rb, Zr and
Th tend to decrease with time but Sr, Pb and Y increase.
Plots of modal abundance versus time (Fig. 4-16) indicate that the total
phenocryst content is high and that temporal variations in these phenocrysts reflect
temporal variations in the major element geochemistry rather than trace element
data. However, except for olivine which reveals a significant positive correlation at 61
the 95% confidence level with MgO and Ti02, there is no significant correlation between modal mineralogy and total-rock geochemical data for Parasitic Cones
(Table 4-11).
4.2.4 Young Ungaran
Total-rock chemical analyses of seven basalt samples, thirteen basaltic andesite samples and ten andesite samples from Young Ungaran are listed in
Appendix D-4 while the major and trace element mean, standard deviation and range are listed in Tables 4-12 to 4-14. Most basalt samples (5) are shoshonites while most basaltic andesite samples (11) and all andesites are high-K calcalkaline
(Fig. 4-1). The averages values for Ti02, total FeO, MgO, CaO and Na20 from
Young Ungaran decrease while K20 increases with increasing silica content
(Fig. 4-2). The Mg-numbers for basalts range from 0.46 to 0.55 (Table 4-12), and the maximum value of the D.I. for samples from Young Ungaran is 54.1
(Table 4-14). The basalts range from Ne-normative to Q-normative when the
Fe203/FeO+Fe203 ratio is assumed to be 0.2, and they are undersaturated to slightly oversaturated if the analysed Fe203/FeO+Fe203 ratio is used in the CIPW norm calculation (Fig. 4-17).
The average values for Sr, V and Sc decrease whereas Rb, Zr, Nb, Th and
Ta increase with increasing silica content (Tables 4-12 to 4-14). The average values for Pb, Y and Hf are relatively high and very similar for all rock types whereas Cr and Co are higher in basalts than basaltic andesites or andesites. REE patterns for basalts (Fig. 4-18) are variable and exhibit a wide range of enrichment in LREE
(LaN = 63.6 to 154.5). All basalts have moderatefractionation of REE (Laf/YoN values = 6.4 to 11.9), and have small negative Eu anomalies (Eu/Eu* = 0.82 to
0.98), except sample 418 (Eu/Eu* = 1.10). Sample 326 has the highest content of
La, medium REE (MREE) and HREE for basalts from Ungaran (Fig. 4-18). The four samples of basaltic andesite have similar REE patterns (Fig. 4-18) and all are enriched in LREE (LaN = 106-155.5), which is typical of the high-K calcalkaline 62
suite. These samples have moderate fractionation with LaN/YbN values between
8.6 and 10.5, and moderate negative Eu anomalies with the Eu/Eu* ratio between
0.81 and 0.85. Compared to other samples of basaltic andesites from Young
Ungaran, sample 821 is more enriched and fractionated in REE. All andesite samples display similar REE patterns (Fig. 4-18) with enrichment in LREE (LaN =
87.6 to 126.9), moderate fractionation (LaN/YbN= 7.2 to 10.2), and moderate negative anomalies (Eu/Eu* = 0.82 to 0.84).
As shown in Appendix D-4, the 87Sr/86Sr ratio for basalts is higher
(0.70498 for sample 326 and 0.70510 for sample 833) than for andesite (0.70487)
and for basaltic andesite (0.70474). Differences between the values for basalt and
andesite are not significant nor is the difference between the ratio for basaltic
andesite and andesite. In contrast, the 87Sr/86Sr ratios for the basalt samples are
significantly higher than the ratio for the basaltic andesite.
Temporal geochemical variations in the thirty samples from Young Ungaran
are complex, and to some extent erratic (Figs. 4-19 and 4-20). For example, lavas
which are the most primitive in terms of having the lowest Si02 and Rb contents
and highest MgO contents (units 9-12) are overlain by lavas which have the
opposite geochemical characteristics (units 13 to 17). In addition, the lavas at the
bottom and top of the sequence (units 1 and 30 respectively) have some
geochemical features in common (e.g. contents of Si02 and MgO) but are very
different in terms of their trace element geochemistry.
The modal contents of plagioclase and clinopyroxene phenocrysts have
positive correlations with AI203, and with Ti02 and total FeO respectively
(Table 4-15). Olivine also has a positive correlation with Ti02, total FeO, MgO and
CaO, and a negative correlation with A1203. Temporal fluctuations in the contents
of many elements (e.g. AI2O3; Fig. 4-19) are reflected by similar fluctuations in the
modal contents of phenocrysts (e.g. plagioclase; Fig. 4-21). 63
4.3 Summary and discussion
4.3.1 Major elements
Major element data for Ungaran rocks are summarized in Table 4-16. Si02 content ranges from a maximum of 60.80% to a minimum of 48.95%, and except for Na20 and K20, all the major elements decrease in abundance with increasing
Si02 (Fig. 4-2). Al203 is relatively high ranging from 17.69 to 20.80%, whereas
Ti02 is relatively low with a range of 0.56 to 1.08%. CaO ranges from 5.14 to
9.99% and total FeO is variable within the range 5.96 to 10.32%. MgO is relatively
low with a maximum value of 5.56%. The range in content of Na20 is not as wide
as for K20, and the K20/Na20 ratio increases with increasing Si02 (Tables 4-17 to
4-19). This ratio ranges between 0.49 and 1.37 (Table 4-16), attaining a maximum
frequency in the 0.80 interval (Fig. 4-22) whereas the mean value of 0.90 is
slightly higher than the ratio for the calcalkaline suites (< 0.8) reported by Jakes
and White (1972).
The rocks of Ungaran volcano are relatively evolved with the maximum
values for the Mg-number and D.I. being 0.55 and 58.7 respectively (Table 4-16).
The low magnitude of the Mg-numbers for Ungaran rocks indicates that the lavas
crystallized from derivative melts and do not represent primary, mantle-derived
magmas.
The chemical features of the Ungaran rocks are illustrated in more detail
with compositional histograms in Figure 4-23. The Si02 distribution emphasizes
the abundance of basaltic andesite, whereas Al203 exhibits a gradually decreasing
frequency toward higher Al203 contents. Values between 0.6 and 0.8% are most
common for Ti02 which supports the proposal that orogenic basalts are
characterized by low Ti02 (Chayes, 1964). Total FeO content is variable whereas
MgO has an asymmetric distribution with the maximum frequency (3% interval)
towards the lower end of the range of values. CaO contents are dominated by
values between 7 and 9%, whereas Na20 has a symmetrical distribution with a
similar frequency of occurrence for all values between 2.6 and 3.6%. The 64
distribution of K20 and P2Os contents are asymmetrical with the highest frequency of values towards the higher and lower end of the ranges respectively (Fig. 4-23).
Other features demonstrated by the major element geochemistry of Ungaran lavas include:
a. The dominant lava type in Ungaran is basaltic andesite (Fig. 4-23) and
the mean silica content of all lavas is 54% (Table 4-16); lavas with
greater than 60% Si02 are almost absent.
b. The average value of Ti02, total FeO, MgO and CaO decreases
from basalt (Table 4-17) through basaltic andesite (Table 4-18) to
andesite (Table 4-19), while Na20 and K20 increase.
c. Basalt samples range from Ne-normative to Q-normative irrespective
of the use in the CIPW calculation of the analysed ratio of
Fe203/FeO+Fe203 or an assumed ratio 0.2. Most of the basalt
samples, however, are saturated if the assumed ratio 0.2 of
Fe203/FeO+Fe203 is used.
d. With the exception of the Parasitic Cones, Si02 and K20 contents of
Ungaran rocks generally increase with time, whereas Ti02, MgO and
CaO decrease.
4.3.2 Strontium
Ungaran rocks have a wide range of Sr contents between 366 to 678 ppm
(Table 4-16; Fig. 4-24). The basalts have the widest range of Sr containing between 380 to 678 ppm (Table 4-17). In basaltic andesites the content of this element ranges from 366 to 645 ppm (Table 4-18), whereas in andesites the values range between 399 and 552 ppm (Table 4-19).
The distribution of data points on the plot of Sr versus Si02 (Fig. 4-24) may be interpreted in several different ways. The scatter precludes derivation of all rock types in a single, simple fractionation model and thus may simply reflect different sources for different samples. Alternatively, the samples may be related by 65
fractionation but the scatter necessitates severalfractionation series. Figure 4-25 shows that the Sr content of the basalts has a negative correlation with the Ca/Sr ratio which is consistent with fractionation of calcic plagioclase (cf. Noble and
Korringa, 1974). The correlation between these parameters for either the basaltic andesites or the andesites, however, is not significant at the 95% confidence level.
In addition, the general decrease in the Ca/Sr ratio in the series basalt to basaltic andesite to andesite is also consistent with plagioclase fractionation. If plagioclase fractionation is important in Ungaran rocks, the rocks with higher Sr contents should reflect plagioclase accumulation which should also be indicated by positive
Eu anomalies. The lack of such anomalies in Ungaran lavas precludes significant plagioclase fractionation.
At the 95% confidence level, Sr has a negative correlation with Si02
(Figs. 4-24; Table 4-20) although the reverse trend is considered a more likely occurrence because large cations usually correlate positively with Si02. This positive correlation has been recorded for some low-K andesites (e.g. Ando, 1975;
Baker, 1978) but negative correlations have also been recorded for other high-K suites besides Ungaran (e.g. Gill, 1981).
4.3.3 Rubidium
Rubidium, in contrast to Sr, correlates positively with Si02 (Fig. 4-26;
Table 4-20). In common with Sr, the wide range of Rb contents, particularly in basalts (13-81 ppm; Table 4-17; Fig. 4-26) may represent more than one liquid line of descent which implies that the lavas have originated from different sources and/or from a single source which has givenrise to several fractionation series.
In terms of K and Rb abundances, the Ungaran rocks are unusual, and although the average K/Rb ratio decreases with increasing silica content (Tables
4-17 to 4-19), the basalts and basaltic andesites have considerable overlap
(Fig. 4-27). Basalts have a high K/Rb ratio (maximum of 894) which is similar to
N-type MORB (Sun and Nesbitt, 1978). The ratio in basaltic andesites ranges 66
between 267 and 501, whereas values for andesites (between 215 and 336) are similar to the K/Rb ratio of average continental crust (Jakes and White, 1970). The
K/Rb ratio of an igneous rock is commonly considered to reflect its differentiation history and source composition (e.g. Jahn et al., 1974). Hence the decrease in
K/Rb ratio towards more felsic rocks in Ungaran is possibly due to fractionation processes (e.g. Shaw, 1968). However if fractionation is negligible, contamination by crustal material with a low K/Rb ratio is also plausible (e.g. Jakes and White,
1970). Irrespective of which processes occurred, the highest value of the K/Rb ratio in the Ungaran rocks may represent the "initial" K/Rb value, and subsequent fractionation or contamination results in a decreasing K/Rb value.
The K/Rb ratio in basalts also reflects the relative roles of amphibole and mica in the source region (Green, 1980). Basalts from Ungaran with relatively high
Rb contents (e.g. sample 918; 81 ppm; Appendix D-2) may have originated from a
source with a higher content of amphibole or mica than basalts with lower Rb
contents (e.g. sample 833; 13 ppm; Appendix D-4).
Figure 4-28 shows a comparison between Sr, K and Rb data for each rock
type in Ungaran with data for equivalent rock types from elsewhere. All data are
normalized to the composition of oceanic floor basalt given by Hart et al. (1970),
and the individual values of Sr, K and Rb used in the comparison are listed in
Table 4-21. Ungaran volcanic rocks constitute a highly evolved suite and have
much higher contents of Rb than oceanic floor basalts, island arc tholeiitic basalts
and calcalkaline andesites. The Sr, K, and Rb contents for basalts and basaltic
andesites from Ungaran closely resemble those of the high-K calcalkaline basalts
from the Highlands of Papua New Guinea (MacKenzie and Chappell, 1972). The
contents of these three elements in Ungaran andesites resembles those of the
high-K calcalkaline andesites from the eastern zone of Western USA (Ewart,
1982). 67
4.3.4 Th, Pb, Zr, Hf, Y, Nb, Ta and Ti
Thorium ranges from 2 to 26 ppm (Table 4-16) and has a significant positive correlation with Si02 (Fig. 4-29; Table 4-20). The average values for each rock type are listed in Tables 4-17 to 4-19 and these values are typical of high-K suites which normally contain more than 5 ppm (cf. Gill, 1981). In general, the Th contents in basalts and basaltic andesites have considerable overlap and have lower contents than the andesites (Fig. 4-29). In addition, the initial lavas within each major stratigraphic unit except Oldest Ungaran, are characterized by relatively high
Th contents (Figs. 4-11,4-15 and 4-20).
According to Jakes and White (1972), Pb values for high-K calcalkaline andesites and shoshonites are between 10 to 15 ppm and the least fractionated basaltic rocks have low Pb values around 3 to 5 ppm. Compared with the values proposed by Jakes and White (1972), Pb concentrations in lavas from Ungaran are extremely high (10 to 33 ppm; Table 4-16). Although the average Pb contents are similar, the basalts have a wider range of values than basaltic andesites and andesites (Tables 4-17 to 4-19; Fig. 4-30). This wide range may reflect different sources for the magma. Alternatively some of the basalts with relatively low Pb contents may be related to the basaltic andesites and andesites byfractionation, bu t basalts with high Pb contents are unlikely to be related to the other rock types by this process.
Zirconium in the Ungaran volcanic rocks ranges in value between 104 and
198 ppm and correlates positively at the 95% confidence level with a variety of elements including Si02 and Rb (Figs. 4-31 and 4-32; Table 4-20). This positive correlation implies minimal or no zircon fractionation. Zr and Hf abundances show a high degree of correlation (Fig. 4-33) and differences in the Zr/Hf ratios for rocks from Ungaran may reflect derivation of the magma from sources with different Zr and Hf contents, or by different degrees of partial melting of a single source, or the effects of fractional crystallisation. 68
The Y content of most samples from Ungaran is within the range of 22 to
35 ppm (Table 4-18; Fig. 4-34), but sample 917 has an anomalously high value of
52 ppm (Appendix D-3). High contents of Y normally reflect the presence of abundant apatite but this is not a plausible explanation for this sample because neither the modal content of apatite nor the whole-rock P2O5 content are anomalous for samples from Ungaran. The other common minerals which readily accommodate Y are garnet and amphibole (Lambert et al., 1974). However, garnet is absent from sample 917 and amphibole occurs only in small amounts (3%,
Appendix B). The most plausible explanation for the anomalous Y content is that it is inherited from the source region.
Niobium has a restricted range from 6 to 18 ppm (Table 4-16) and overall it has significant correlation with several elements including Si02 and Ta (Table 4-20;
Figs. 4-35 and 4-36). In contrast to rubidium, Ti has an antipathetic relationship with potassium (Table 4-20) and the K/Ti ratio increases with increasing silica
content (Fig. 4-37). This pattern of K versus Ti for Ungaran lavas reflects the effect of fractionation of Fe-Ti oxide and is not consistent with the general pattern across the Sunda-Banda Arc as described by Wheller et al. (1987), where Ti shows
a positive correlation with K. The progression from tholeiitic to leucititic rock suites
in the Sunda-Banda Arc is accompanied by an increase in the K/Ti ratio
(Wheller et al., 1987). Similarly, the progression from high-K calcalkaline to
shoshonitic rocks in Ungaran is also accompanied by an increase in the K/Ti ratio.
4.3.5 Co, V, Sc and Cr
Compatible element contents for Ungaran rocks are plotted in Figures
4-38 to 4-41 as a function of Si02 content. The decreases in Co, V, Sc and Cr with increasing Si02 accord with fractional crystallisation of olivine, clinopyroxene, plagioclase and Fe-Ti oxide (cf. Wyers and Barton, 1986). Decreases in Co content through a rock series suggest fractionation of Mg-rich olivine. Differences in Co content in rocks with similar Si02 contents (e.g. 19 ppm for sample 917 and 40 69
ppm in sample 832), suggests that these rocks have had different degrees of olivine fractionation or different sources. Vanadium is readily accommodated into the
lattice of Fe-Ti oxide whereas Cr readily substitutes in clinopyroxene. The marked
decrease in both these elements with increasing silica suggests fractionation of
Fe-Ti oxide and clinopyroxene respectively. Samples which depart markedly from
the regression lines defining the relationships between Si02 and compatible element
contents are probably derived from different sources.
4.3.6 Rare earth elements
Rare earth element patterns for rocks from Oldest Ungaran (Fig. 4-4) are
moderately fractionated with (La/Yb)^ values between 5.6 and 8.8 and slight
negative Eu anomalies with Eu/Eu* between 0.82 and 0.91.
Samples from Old Ungaran are characterized by enrichment in LREE (La^
between 54.2 and 147.3), low to moderate fractionation (La/YbN = 4.4 to 16.9)
and slight negative Eu anomalies (Eu/Eu* = 0.86 to 0.95). Basalt sample 832 is the
least fractionated and has a much lower LREE content (LaN = 54.2) compared to
the other basalts (La^ = 104.2 to 147.3). Sample 820 has the most fractionated
REE pattern for samples from Old Ungaran (Fig. 4-9) and has a (LaJYb)i^ ratio of
16.9.
Rare earth elements in lavas from Parasitic Cones (Fig. 4-13) show similar
patterns and are enriched in LREE (La^ = 88.4 to 93.3), with moderate
fractionation as indicated by the (La/Yb)N ratio between 7.8 and 8.3, and have
small Eu anomalies (Eu/Eu* = 0.79 to 0.86). The exception is sample 919 which is
characterized by a lower enrichment in LREE (La^ = 56.7), slight fractionation
(LaN/YbN = 4.7) and a positive Eu anomaly (Eu/Eu* = 1.08).
As shown in Figure 4-18, rocks from Young Ungaran have a wide range of
enrichment in LREE (LaN = 63.6 to 155.5), moderatefractionation (La/Yb)N = 6.4
to 11.9, and negative Eu anomalies (Eu/Eu* = 0.76 to 0.98; except sample 418
with Eu/Eu* = 1.10). 70
Overall the rocks from Ungaran are characterized by enrichment in LREE, moderate fractionation of REE and most samples have slight negative Eu anomalies. These features are typical of high-K calcalkaline and shoshonitic rocks.
Negative Eu anomalies are normally interpreted as resulting from removal of plagioclase and the relatively small magnitude of these anomalies in rocks from
Ungaran implies that plagioclase fractionation is not a major mechanism in the petrogenesis of these rocks. More discussion of REE patterns is presented in
Chapter 6.
4.3.7 Strontium isotopes
Strontium isotopic analyses are presented for 21 samples from Ungaran including data for nine samples from Whitford (1975b). All new 87Sr/86Sr analyses are listed in Appendix D and the relationships of the isotopic data with major and trace element contents are shown in Figures 4-42 and 4-43.
Although Ungaran lavas have been erupted over a relatively short period of time (Chapter 2) and are closely related geochemically, significant differences exist in the Sr isotopic ratios for the lavas. The most important features of these isotopic data comprise:
1, Rocks from Ungaran have 87Sr/86Sr ratios which can be divided into two groups on the basis of their Si02 contents (Fig. 4-42). Rocks with less than 53% Si02 (essentially basalts) have a wide range of
87Sr/86Sr ratios and a mean of 0.70503 whereas rocks with greater than 53% Si02 (basaltic andesites and andesites) have a more restricted range of values and a mean of 0.70489. These two groups are well defined for the relationship of the 87Sr/86Sr ratio to some other major element oxides (e.g. FeO, MgO, K20, Ti02 and CaO) but are not apparent on the plots of the isotopic ratio versus AI2O3, Na20, Sr or
Rb/Sr (Figs. 4-42 and 4-43). 71
2. The 87Sr/86Sr ratio does not correlate with major or trace element data when all samples are considered (Table 4-22).
3. Si02, MgO, CaO and Ti02 have significant (95% confidence level)
87 86 correlation with Sr/ Sr for rocks with < 53% Si02, whereas Al203,
87 86 FeO, Na20 and Rb show significant correlation with Sr/ Sr for samples with > 53% Si02.
4. There is no consistent variation between 87Sr/86Sr and time (Fig. 4-44).
5. The 87Sr/86Sr ratio for rocks from Ungaran is relatively high compared with the calcalkaline and leucititic rocks from Java
(Fig. 4-45).
4.3.8 Temporal variations and models for magma chamber
Variation in the mineralogy and total-rock geochemistry of volcanic sequences deposited during one eruptive epoch (i.e. during the short term) commonly reflect conditions in the magma system before eruption begins, although they may occasionally reflect fractional crystallisation during an eruption. For example, Hildreth (1979) noted that the earliest eruption of the Bishop Tuff contains a low abundance of ferromagnesian minerals whereas later eruptions become progressively more mafic. A similar variation also occurs within lavas of
Hawaiian volcanoes (Wright and Fiske, 1971). These features indicate that these compositional changes are related to processes within magma chambers or reservoirs before eruption commenced (e.g. Smith, 1979).
Except for the Parasitic Cones, the short term variations in Oldest, Old and
Young Ungaran show a reverse trend to the Bishop Tuff and Hawaiian volcanoes.
Eruptions from Oldest, Old and Young Ungaran always commenced with basalt or basaltic andesite and ended with andesitic lavas. In general, temporal variations in the major element geochemistry of lavas from Oldest, Old and Young Ungaran are similar. They increase in Si02 and K20, and decrease in TiC^, MgO, total FeO and
CaO (Section 4.3.1), whereas these elements show a reverse trend for lavas from 72
the Parasitic Cones. These variations presumably reflect differences in the magma chamber below Ungaran and possible models for the production of these variations are listed below. 1. The magma chamber beneath Ungaran may have been vertically
stratified due to crystal fractionation and eruptions tapped
progressively deeper levels of the chamber.
2. Infrequent influxes of basaltic magma into a shallow reservoir, and
subsequent fractionation to more evolved compositions. Each influx
of fresh basaltic magma would tend to mix with and/or cause
eruption of magma in the reservoir.
3. Frequent influxes of basaltic magma into a shallow magma reservoir.
4. Mixing of felsic country rock or silicic magma with basaltic
magma. Thus, during passage to the surface both fractionation and
contamination occurred to generate more evolved lavas.
5. Lavas are generated from several different parental magmas.
The fust model is viable to explain the eruption products of the Parasitic
Cones which commence with andesite and essentially become increasingly more
mafic with increasingtime. This model, however, does not explain the short term
variations for Oldest, Old and Young Ungaran unless the magma chamber was
subjected to periodic convective overturn or the initial eruptions resulted from
tapping the magma reservoir at lower levels instead of at the top.
In the second model, the infrequent influx of fresh magma into the shallow
reservoir should be followed by maxima in the modal contents of phenocrysts
which represent the fractionating phases. In addition, compositional data for
plagioclase should have a bimodal distribution; one population representing the
fractionating phases and the other representing the phase in equilibrium with the
erupted magma. This type of distribution does occur in some lavas from Ungaran
(Section 3.6.1). However, the model is not entirely satisfactory because 73
fractionation in the shallow magma reservoir should produce evolved rocks
(e.g. dacites) but the maximum Si02 content for Ungaran lavas is 60.80%.
Assuming that magma was resident in the shallow magma reservoir for sufficient time to permit at least some crystallisation, evidence for the the third model would be essentially the same as for the second model except for the formation of evolved rocks. Frequent influx of fresh magma would preclude substantial fractionation. The lack of evolved rocks in Ungaran supports this model.
Petrographic evidence for the mixing model is restricted to the existence of a bimodal distribution for plagioclase compositions in some samples. Isotopic data,
87 86 particularly the lack of correlation between Sr/ Sr and Si02, K20, Sr and Rb/Sr
(Section 4.3.7), are also contrary to this model.
Model five is difficult to evaluate. Certainly the scatter observed in trace element plots against Si02 (Figs. 4-24, 4-29 to 4-31, 4-34, 4-38 to 4-41) may possibly be due to derivation of these lavas from several sources. Strontium isotopic data indicate that although some basalt samples cannot be related to basaltic andesites and/or andesites within same group (e.g. Old Ungaran), the data do not negate fractionation relationships between groups. For example, the basalt from
Old Ungaran (sample 832; 87Sr/86Sr = 0.70519) cannot be related to the basaltic andesite (sample 820; 87Sr/86Sr = 0.70467) and andesite (sample 924; 87Sr/S6Sr =
0.70477) from the same group, but it could be related by fractionation to the basaltic andesite from the Parasitic Cones (sample 425 ; 87Sr/86Sr = 0.70527) at the
95% confidence level. Furthermore, basalt from Young Ungaran (sample 326;
87Sr/86Sr = 0.70498) could be related to andesites from the Parasitic Cones and
Oldest Ungaran (87Sr/86Sr = 0.70497 for samples from both units) by fractionation processes but not to basaltic andesites from any of the groups (^Sr/^Sr ratios are
0.70467, 0.70474 and 0.70527). The Sr isotopic data demonstrate that basalt from
Old Ungaran may be derived from different parent material than basalt from Young
Ungaran. In addition, simple fractionation is not adequate to relate any of the 74
basalts from Ungaran to basaltic andesites from Old and Young Ungaran (87Sr/86Sr
= 0.70467 and 0.70474 respectively) or the andesite from Old Ungaran (87Sr/86Sr
= 0.70477). These data are consistent with the possibility that these basaltic andesites and andesite may have evolved from more primitive basalt or were derived from different parent material to the basalts from Old and Young Ungaran.
The five models are not mutually exclusive and the observed variations may be due to combinations of two or more models. More detailed discussion of processes such as fractionation and contamination is presented in Chapter 6. 75
CHAPTER 5
MAGMATIC AFFINITIES
5.1 Introduction
Many island arcs show an evolutionary sequence commencing with tholeiitic magmatism in the early stages of development, through a period of calcalkaline to high-K calcalkaline compositions and ending with shoshonitic magmatism.
However, most of these evolutionary sequences overlap in time and space
(e.g. Baker, 1968; Jakes and White, 1969, 1972; Jakes and Gill, 1970; Gill, 1970,
1981; Wheller et al., 1987). This simple evolutionary sequence has had a major influence on models proposed for magma genesis in many island arcs
(e.g. Nicholls and Ringwood, 1972, 1973; Ringwood, 1974, 1975).
The volcanic rocks of Java Island can be divided chemically into the tholeiitic, calcalkaline, high-K calcalkaline, shoshonitic and leucititic suites
(e.g. Wheller et al., 1987). The distribution of these suites conforms to the regular pattern of increasing potassium content across the Sunda Arc away from the
Benioff Zone (Whitford et al., 1979a). In contrast to some island arcs, the early stages of development of Java, which were related to a Tertiary subduction zone, appear to be dominantly calcalkaline in character with minor development of tholeiitic magmas (van Bemmelen, 1949; Whitford and Nicholls, 1979a). From oldest to youngest, this calcalkaline episode was followed by leucititic, shoshonitic, high-K calcalkaline, calcalkaline and tholeiitic magmatism. This atypical order of chemical variation with time is also exhibited in some other island arcs including, for example, the New Hebrides where Miocene calcalkaline lavas are overlain by dominantly tholeiitic lavas (Gorton, 1974). Westercamp and
Mervoyer (1976) have noted that tholeiitic and calcalkaline lavas are intercalated at several stratigraphic levels on Martinique, and the temporal sequence of chemical variation does not conform to the more usual sequence of increasing aJJcalinity. 76
5.2 Shoshonites
Many authors have used the term shoshonite but the meaning of the term is
equivocal. For example, Joplin (1968) defined shoshonites as potassium-rich
rocks, showing some affinities with calcalkaline rocks, and commonly associated
with near silica saturated rocks including leucite-bearing types. Jakes and White
(1972) pointed out the gradational relationship between tholeiitic, calcalkaline and
shoshonite magmas whereas Kesson and Smith (1972) proposed that all mafic
lavas (< 50% Si02) with low Ti02 (< 1.3%) are shoshonitic. Whitford et al.
(1979a) excluded the term shoshonite for their work on Indonesian lavas and
proposed the term high-K calcalkaline which also partly overlaps the calcalkaline
field of other workers (e.g. Peccerillo and Taylor, 1976a), but it is distinct from the
high-K alkaline field. The geochemical characteristics of shoshonites have been
reviewed by Morrison (1980) and in this thesis the shoshonitic and high-K
calcalkaline associations are defined on the basis of contents of K20 and Si02
(Fig. 1-2). The characteristics identified by Morrison (1980) together with the
relevant data for rocks from Ungaran are presented in Table 5-1.
The shoshonitic rocks from Ungaran are near-saturated with silica and range
from Ne-normative to Q-normative when the analysed Fe203/Fe203+FeO ratio is
used for the CIPW norm calculation (Fig. 5-1). Most samples from Ungaran are
saturated when the CIPW norm is calculated using an assumed value of 0.2 for
Fe203/Fe203+FeO (Hughes and Hussey, 1976).
In terms of the Fe^/FeO ratio (Fig. 5-2), the shoshonitic rocks from
Ungaran are similar to Morrison's shoshonites. However, the significance of these
data is debatable since the extent of post-emplacement oxidation is unknown.
Morrison's review indicates that shoshonites are characterised by low-iron
enrichment. This feature is also demonstrated in Ungaran by a relatively flat trend
on the AFM plot (Fig. 5-3). Similarly, the total alkali content of the Ungaran rocks
is generally high (> 5%, Fig. 5-4), and the K20/Na20 ratio is also high (> 0.6 at
50% Si02, > 0.8 at 54.5% Si02; Fig. 5-5). The K20 versus Si02 trend (Fig. 5-6) 77
and content of LIL elements (Ba, Rb, K, Th and Sr) for Ungaran rocks are also characteristic of the shoshonitic association (Table 5-2).
Lavas from Ungaran contain up to 1.08% Ti02 (Fig. 5-7) which is lower than the maximum value of 1.3% suggested by Morrison (1980). Al203 contents of shoshonitic rocks from Ungaran range from 18.22 to 20.80% (Fig. 5-8) which is slightly higher than the maximum value of 19% suggested by Morrison (1980).
Inspection of Table 2 of Morrison (1980), however, shows that the Al203 content of shoshonitic rocks ranges between 11.94 and 20.05%, close to that shown by approximately 90% of Ungaran shoshonitic rocks (Fig. 5-8).
The petrography of shoshonitic rocks is characterized by Ca-rich and
Ti-poor clinopyroxene which plots in the augite and salite fields and lacks
Fe-enrichment (Joplin et al., 1972). Plagioclase is characterized by normal and oscillatory zoning with sanidine rims on labradorite phenocrysts, and coexisting plagioclase and sanidine in the groundmass (Nicholls and Carmichael, 1969). The shoshonite rocks from Ungaran show all of these features, and also exhibit many petrographic similarities with calcalkaline and tholeiitic lavas from other volcanoes in Java (cf. Whitford, 1975a).
5.3 High-K calcalkaline rocks
The term high-K calcalkaline is used in this thesis to describe the most potassic representatives of the calcalkaline suite. Thus, they are considered separate from the calcalkaline and shoshonite suites on the basis of the potassium content, and the high-K calcalkaline field is shown in Figure 4-1. The term calcalkaline is used by most petrologists today instead of subalkaline for compositions between low-K or tholeiitic and alkaline. Petrographicaily, the high-K calcalkaline rocks of
Ungaran show many similarities to the tholeiitic and calcalkaline lavas of other volcanoes in Java (cf. Whitford, 1975a), but are very different in mineralogy from the alkaline rocks described by Whitford (1975a). The high-K calcalkaline rocks are all porphyritic with phenocrysts of plagioclase, Ca-rich clinopyroxene, olivine 78
in the mafic lavas, Fe-Ti oxide, and some amphibole and/or biotite. The groundmass is mostly fine-grained and consists of microlitic feldspar, clinopyroxene, and Fe-Ti oxide. In contrast, the alkaline rocks of the "Dry Series"
(Whitford, 1975a) are porphyritic with phenocrysts of Ca-rich clinopyroxene, olivine, Fe-Ti oxide, rare green-brown amphibole and Mg-rich mica, together with minor feldspar and leucite. The groundmass consist of clinopyroxene, olivine, Fe-
Ti oxide, feldspars and feldspathoids. The alkaline rocks of the "Wet Series"
(Whitford, 1975a) are characterized by the abundance of anhedral, poikilitic and hydrous phenocrysts such as amphibole and mica. Feldspar is more common in the groundmass than feldspathoid.
The high-K calcalkaline rocks from Ungaran range from Hy-normative to
Q-normative when the analysed Fe203/Fe203+FeO ratio is used for the CIPW norm calculation (Fig. 5-1). Most samples from Ungaran are saturated when the
CIPW norm is calculated using an assumed value of 0.2 for the Fe203/Fe203+FeO ratio (Hughes and Hussey, 1976). The Fe203/FeO is high (Table 5-3; Fig. 5-2) although the significance of these data is debatable due to the unknown extent of post-emplacement oxidation.
Compared to the shoshonitic rocks in Morrison's list, the high-K calcalkaline rocks of Ungaran are characterized by low-iron enrichment, as is demonstrated by the flat trend on the AFM plot (Fig. 5-3). Similarly, the total alkali content of the Ungaran rocks is generally high (> 5%, Fig. 5-4), and the
K20/Na20 ratio is also relatively high (> 0.7 at 55% Si02; Fig. 5-5). The K20
versus Si02 trend (Fig. 5-6) is relatively steep, and except for Sr the average LILE contents for the high-K calcalkaline rocks (Table 5-3) are higher than that for the
shoshonitic rocks. Ti02 contents of high-K calcalkaline rocks of Ungaran range up
to 1.08%, but are mostly between 0.6 and 0.8 % (Fig. 5-7). A1203 contents range
from 17.69 to 20.36%, with the majority in the range 18-19% (Fig. 5-8). 79
5.4 Comparison of shoshonitic and high-K calcalkaline rocks from Ungaran
Jakes and White (1972) observed that calcalkaline associations tend to be more silicic than shoshonites, and this observation may be true for the rocks from
Ungaran because approximately 90% of the basalts are shoshonitic and all andesites are high-K calcalkaline (Fig. 4-1). In addition, the early stages of
Ungaran magmatism are dominated by shoshonitic rocks, and the high-K calcalkaline rocks appear to be characteristic of the later stages of the magma evolution (Fig. 5-9).
In terms of major element contents, the shoshonitic rocks from Ungaran
(Table 5-2) have lower Si02, Na20 and K20 but higher Ti02, total FeO, MgO and
P205 than the high-K calcalkaline rocks (Table 5-3).
Trace element data for shoshonitic rocks from Ungaran (Table 5-2) are characterized by lower contents of incompatible elements including Rb, Zr, Nb,
Pb, Th, Y, Hf, Ba, Zn and Ta than high-K calcalkaline rocks (Table 5-3). Average compatible element (Cr, V, Sc and Co) are higher in the shoshonitic rocks than in the high-K calcalkaline rocks (Tables 5-2 and 5-3).
The REE contents in both rock suites are similar but, in general the shoshonitic rocks have a higher average content than the high-K calcalkaline rocks
(Tables 5-2 and 5-3).
5.5 Comparison with other shoshonitic rocks
Analytical data for shoshonitic basalts and basaltic andesites from Ungaran can be compared with analytical data for rocks from a wide variety of tectonic and geographic regions. Because the term shoshonite used in this thesis is based on geochemical data (Fig. 1-2), some rocks termed shoshonites in the literature have been excluded from this comparison. For example, some rocks from Aeolian
Island (Keller, 1974) and the Alban Hills Roman Province (Peccerillo, 1985) which have been described as shoshonites are unusuallyrich i n potassium and plot in the leucititic rather than shoshonitic field. 80
5.5.1 Basalts
Comparison of major element geochemical data for shoshonite basalts from many regions (Table 5-4) shows that these rocks form a coherent gToup. Data for
Ungaran basalts fall near the middle of the range of values for all regions with the exception of relatively higher A1203 and lower MgO. Shoshonitic rocks from
Northwestern Alps (Venturelli et al., 1984; Table 5-4, column J) have much lower values for A1203 and Na20 than similar rocks from elsewhere.
The Ungaran rocks have slightly lower Rb, Sr, Zr and Pb contents compared with shoshonitic basalts from elsewhere but have very similar Sc, Co and Y abundances, and a relatively high content of Zn. The REE, Rb, Sr and Zr contents of Ungaran basalts are indistinguishable from those of the Andean shoshonitic basalts (Keller, 1974; Table 5-4, column E), but the contents of some trace elements (e.g. Cr and V) are very different. The abundances of medium (Sm and Eu) and heavy (Yb and Lu) REE for the shoshonitic basalts from Ungaran are similar to the Permian Sydney Basin (Carr, 1984; Table 5-4, column I), but the contents of Sr and Zr are very different. Shoshonitic basalts from South Rhodope,
Greece (Eleftheriadis et al., 1984; Table 5-4, column L) have consistently lower contents of REE than similar rocks from other regions. In contrast, shoshonitic basalts from Patmos, Greece (Wyers and Barton, 1986, 1987; Table 5-4, column
K), and Mt Vulsini, Italy (Civetta et al., 1981; Table 5-4, column M), contain higher contents of light (La and Ce), and medium (Sm and Eu) REE than similar rocks from elsewhere.
5.5.2 Basaltic andesites
A compilation of published whole-rock geochemical data for shoshonitic basaltic andesites from various regions is shown in Table 5-5. Most of the major elements form a coherent group with the majority of the data from Ungaran occurring in the middle of the range of values for all regions. The exceptions are
A1203 which is relatively high, and MgO and P205 which are relatively low. Both 81
Na20 and K20 for shoshonitic basaltic andesites from Bulgaria are relatively high
(Manetti et al, 1979; Table 5-5, column H).
The trace element data for Ungaran rocks are within the range of values for
all regions. Shoshonitic basaltic andesites from Aeolian Island (Keller, 1974; Table
5-5, column D) and the eastern belt of Western USA (Ewart and Le Maitre, 1980;
Table 5-5, column I), have much higher contents of Sr, while rocks from the
Sydney Basin (Carr, 1984; Table 5-5, column G) have relatively low Ni and Cr,
but higher V than similar rocks from elsewhere.
5.6 Comparison with other high-K calcalkaline rocks
A compilation of published whole-rock geochemical data for high-K
calcalkaline rocks from various part of the world is presented in Tables 5-6 to 5-8.
Comparisons between these rocks and the high-K calcalkaline rocks from Ungaran
are discussed below.
5.6.1 Basalts
Comparison of major element geochemical data for high-K calcalkaline
basalts from many regions (Table 5-6) shows that these rocks form a coherent
group, and that the data for Ungaran rocks lie near the middle of the range of
values for all regions. The exception to this generalisation is the relatively high
Al203 and low MgO for the samples from Ungaran. High-K calcalkaline rocks
from Central Parana (Bellieni et al., 1986; Table 5-6, column J) have much higher
values for Ti02 and total FeO, but lower contents of A1203 and MgO.
The trace element data for Ungaran basalts also lie near the mid-point of the
range of values for other regions (Table 5-6). The major exception is the content of
Cr which is lower than for other regions. Compared to other regions, the
concentration of REE in Ungaran rocks, with the exception of rocks from the
Western USA (Ewart, 1982; Table 5-6, column C and D) and Central Parana
(Bellieni et al, 1986; Table 5-6, column J), is relatively high. The light REE 82
(La and Ce) contents of Ungaran samples show a similar abundance to that in rocks from the Mediterranean area (Ewart, 1982; Table 5-6, column F). Basalts from
North Wales (Kokelaar, 1985; Table 5-6, column L) have the lowest REE values whereas La, Ce and Yb abundances for Western USA basalts (Ewart, 1982; Table
5-6, column C and D) represent the highest values compared with other regions.
5.6.2 Basaltic andesites
A compilation of published whole-rock geochemical data for high-K
calcalkaline basaltic andesites from various regions is shown in Table 5-7. Most of
the major elements form a coherent group with the Ungaran data occurring near the
middle of the range of values for all regions, except for the higher contents of
Al203 and lower MgO abundances. Rocks from Central Parana (Bellieni et al.,
1986; Table 5-7, column K) have much higher Ti02 and lower Al203 than similar
rocks from elsewhere.
In general, the trace element data for Ungaran basaltic andesites are within
the range of values for all regions except for higher contents of Rb, Pb and Th, and
lower contents of Cr and Co. High-K calcalkaline basaltic andesites from Western
USA (Ewart, 1982; Table 5-7, column C and D) have much higher contents of Sr,
whereas rocks from Puerto Rico (Jolly, 1971; Table 5-7, column G) contain
relatively low Rb and Th, but high Cu compared with similar rocks from
elsewhere. The light REE (La and Ce) and heavy REE (Yb) contents of high-K
calcalkaline basaltic andesites from Ungaran fall within, and near the middle of, the
range of values for many regions. Rocks from Ungaran have very similar
abundances of most trace elements to high-K calcalkaline basaltic andesites from
South America (Ewart, 1982; Table 5-7, column E), but the average Cr content in
Ungaran rocks is much lower. The REE data for the rocks from east Carphatian
(Peccerilio and Taylor, 1976b) are anomalous in that these rocks contain the lowest
values compared with other regions. 83
5.6.3 Andesites
In common with basalts and basaltic andesites, comparison of major element geochemical data for high-K calcalkaline andesites from many regions (Table 5-8) show that these rocks also form a coherent group in which the data for Ungaran rocks lie near the middle of the range of values for all regions. The Ungaran rocks display relatively high Al203 abundances. High-K calcalkaline andesites from
Aeolian Island (Keller, 1974; Table 5-8, column H) have much lower Ti02 values, and rocks from the Andes (Dostal et al., 1977; Table 5-8, column J) have anomalously low MgO.
The trace element contents of Ungaran rocks fall near the middle of the range of values for all regions documented in Table 5-8. The rocks from Western
USA (Ewart, 1982; Table 5-8, column C and D) contain the highest contents of Sr whereas Rb from high-K calcalkaline rocks of Greece (Pe-Piper, 1983; Table 5-8, column L) are the lowest. Ni, Cr and Co in rocks from Aeolian Island
(Keller, 1974; Table 5-8, column H) are much lower compared with similar rocks from elsewhere.
High-K calcalkaline rocks from Ungaran have similar light REE contents to the rocks from South America (Ewart, 1982; Table 5-8, column E). The light REE contents for rocks from the Mediterranean (Ewart, 1982; Table 5-8, column F) are lower than for rocks from elsewhere.
5.7 Summary
On the basis of K20 and Si02 contents (Fig. 4-1), the volcanic rocks from
Ungaran are typical of the shoshonitic and high-K calcalkaline rock associations.
Shoshonitic rocks dominated the early stages of magmatic activity in Ungaran whereas high-K calcalkaline rocks were produced during later stages. More evolved rock types are developed in the high-K calcalkaline suite than in the shoshonite suite. However, both the shoshonites and high-K calcalkaline rocks 84
from Ungaran volcano are characterized by relatively high contents of A1203 and low contents of MgO, Cr and V.
Petrographically, the Ungaran shoshonites are typical of shoshonitic rocks from throughout the world, whereas the high-K calcalkaline rocks show many similarities with the tholeiitic and calcalkaline rocks of Java island. Both the shoshonitic and high-K calcalkaline rocks of Ungaran are very different in mineralogy from the high-K alkaline rocks described by Whitford (1975a).
The shoshonitic rocks from Ungaran (Table 5-2) have lower contents of
Si02, Na20, K20 and incompatible trace elements including Rb, Zr, Nb, Pb,
Th,Y, Hf, Ba, Zn and Ta than high-K calcalkaline rocks (Table 5-3). In contrast, the shoshonitic rocks from Ungaran have higher contents of Ti02, total FeO, MgO,
P205 and compatible elements (Cr, V, Sc and Co) than the high-K calcalkaline rocks (Tables 5-2 and 5-3). The REE contents are very similar for both rock associations but the shoshonitic rocks tend to have higher average contents than the high-K calcalkaline rocks (Tables 5-2 and 5-3). In the AFM and Na20-CaO-K20 plots the shoshonitic rocks show a more restricted range of compositions than the high-K calcalkaline rocks (Fig. 5-3). The maximum frequency for the Fe203/FeO ratio (Fig. 5-2) and total alkali content (Fig. 5-4) is lower for the shoshonitic association than for the high-K calcalkaline rocks, but the reverse situation occurs for Ti02 content (Fig. 5-7).
Comparison of geochemical data for shoshonitic and high-K calcalkaline rocks from various tectonic and geographic regions shows that the rocks of each association form a coherent group, and that most of the Ungaran rocks fall near the middle of the range of values. The REE contents for Ungaran shoshonitic basalts are indistinguishable from those of Andean rocks (Keller, 1974), whereas the heavy REE (Yb and Lu) and medium REE (Sm and Eu) contents are very similar to those of Permian basaltic rocks from the Sydney Basin (Carr, 1984). The light
REE (La and Ce) contents of high-K calcalkaline basalts from Ungaran are similar to those in equivalent rock types from the Mediterranean. The REE contents of 85
high-K calcalkaline basaltic andesites and light REE (La and Ce) contents for andesites from Ungaran show a close resemblance to similar rock types from South America (Ewart, 1982). 86 87
CHAPTER 6
PETROGENESIS
6.1 Introduction
Models for the origin of igneous rocks in island arcs have developed in parallel with the evolution of plate tectonic theory and have been constrained by data derived from experiments on the melting and crystallisation behaviour of rocks of appropriate compositions. In the last decade in particular, utilization of trace element and isotopic data has provided additional constraints for these models.
Most models relate the generation of island arc magmas to processes associated with subduction (e.g. Gill, 1981) and the proposed source region for these magmas has included the crust, mande and subducted oceanic lithosphere
(e.g. Ringwood, 1975; Green, 1980; Gill, 1981; Taylor and McLennan, 1985).
The petrogenetic model proposed for one island arc, however, is not necessarily fully applicable to other island arcs. For example, the contamination model of
Davidson (1986) for the petrogenesis of magmas in the Lesser Antilles is not applicable to the Vanuatu Arc where lavas have been interpreted by Barsdell (1988) as having crystallized from uncontarninated mande-derived melts.
Important features for models for the petrogenesis of Ungaran rocks include the occurrence of mafic, high-K calcalkaline and shoshonitic lavas, and the apparent lack of tholeiitic and normal calcalkaline rocks (Chapters 4 and 5) combined with the tectonic setting involving subduction of the Indian-Australian
Plate beneath the Eurasian Plate (Chapter 2). In this setting, potential source regions for Ungaran magmas comprise the lower crust, the subducted oceanic crust and the mande wedge above the subducted slab. 88
6.2 Crust as the source region
A geothermal gradient of 3 to 4°C/100 m is accepted by many workers as being typical of the geothermal gradient in magmatic arcs (Oxburg and Turcotte,
1971). This gradient is sufficiendy high to induce magma generation in the lower crust at depths of between 20 and 30 km depending on the water content of the source (Gill, 1981). The crust beneath Ungaran has a thickness of between 20 and
25 km (Section 2.2) and the geothermal gradient in the northern part of central Java
(i.e. north of Ungaran) is 4 to 5°C/100 m (Hamilton, 1979). The combination of these features appears to make magma generation in the crust a very real possibility for this region.
One of the major problems facing any model for magma genesis in the lower crust is the lack of definitive data for the mineralogy and geochemistry of this region. Certainly the lower crust is heterogeneous and the predominance of gabbroic and granulitic xenoliths in rocks from island arcs suggests compositions of this type (Griffin and O'Reilly, 1987). The precise composition of the crust beneath Ungaran, however, is not known.
The maximum Si02 content of the lavas from Ungaran is 60.80% and the mean for all samples is 54% Si02. This occurrence of mafic to intermediate compositions and the complete lack of silicic compositions suggests that the continental crust is an unlikely source region. Even complete fusion of average continental crust will produce a magma with the composition of an orogenic andesite (Gill, 1981) and will not produce the mafic lavas present in Ungaran. The only possibility is fusion of material more mafic than average continental crust.
This possibility, however, introduces even more problems. If the LILE concentrations observed for Ungaran are inherited from the source and were not attained subsequent to magma generation (Section 6.5.6), production of the
Ungaran magmas from a mafic crust is unlikely. The high concentration of LILE in the lavas from Ungaran imply low degrees of partial melting (Section 6.4.4) whereas the major element compositions could be achieved only by relatively high 89
degrees of partial melting of mafic material. In addition, the Pb, Sr, and Nd
isotopic data for lavas from Ungaran plot within the mantle array (Sections 6.5.2
and 6.5.3) and support the case for a mantle source.
6.3 Subducted lithosphere as the source region
A close relationship between contents of incompatible elements and depth to
the Benioff Zone has been regarded by many authors (e.g. Dickinson, 1968;
Marsh and Carmichael, 1974) as evidence that the subducted oceanic crust has a
substantial input into magma genesis in many island arcs. The oceanic lithosphere
is considered to be a 5 to 10 km thick, layer of basaltic oceanic crust which is often
overlain by a thin veneer of sediments, and which overlies depleted mantle
(Middlemost, 1985).
A popular hypothesis for the origin of island arc basalts is the generation of magma by partial melting of the subducted basaltic layer of the oceanic crust, with or without input from a sedimentary component (e.g. Green and Ringwood, 1968;
Boettcher, 1977; Stern and Wyllie, 1978; Weaver and Tarney, 1982). During subduction, the oceanic crust descends into the mande and the metamorphic grade changes from greenschist to amphibolite facies as a result of the increase in both temperature and pressure. At depths of between approximately 80 and 125 km
(Gill, 1981) water is released into the overlying mantle wedge and the amphibolite will begin to transform to eclogite at approximately 650 to 700°C (Nicholls and
Ringwood, 1972, 1973). The experimental work of Green and Ringwood (1968) has demonstrated that initial partial melting of eclogite would yield primary magma with an andesitic or more Si02-rich composition. This hypothesis has received support from many investigators throughout the last decade. In a more recent model Brophy and Marsh (1986) proposed that melting of eclogite can produce primary high-alumina basalts. This model, however, has been criticized by
Crawford et al. (1987) who have shown that high-alumina basalts in island arcs 90
are not derived from an eclogitic source but are produced by melting of peridotitic mantle.
Generation of Ungaran lavas by melting of the subducted oceanic slab is inconsistent with the geochemical data for several reasons. In particular, the degrees of partial melting of eclogite required to produce the observed compositions are unlikely to be attained during subduction. The presence of a high proportion of mafic lavas (47-56% Si02) in Ungaran requires high degrees
(40-60%) of partial melting of eclogite which is unlikely to occur. In addition, the high degrees of partial melting required for this model are inconsistent with the observed relatively high contents of K20 which imply small degrees (<13%) of partial melting (Section 6.4.4). The low values for both the Ca content and the
A1IV/A1VI ratio in pyroxene in even the most mafic Ungaran lavas indicate low pressure fractionation (Section 3.6.8), and thus, necessitate even higher degrees of partial melting of an eclogitic source.
Trace element contents of Ungaran lavas, particularly REE data, are inconsistent with this model. If the liquids were derived from an eclogitic source, then it must be strongly depleted in HREE (e.g. Gill, 1981). The depletion of
HREE is caused mainly by the high partition coefficients for garnet and coexisting
basaltic to andesitic liquids (e.g. Dy0 = 5 to 44; Nicholls and Harris, 1980).
Observed REE abundances in most island arc lavas are not consistent with being derived from a garnet-bearing source (e.g. Ewart and Bryan, 1973; Gill, 1981).
The relatively flat HREE patterns for Ungaran rocks (Fig. 6-1) indicate that garnet
is absent from the source material, or at most, it is a minor phase.
6.4 Mantle as the source region
6.4.1 Primary and derivative magmas
Primary basaltic magmas may be defined as magmas that have been
unmodified by crystalfractionation, o r other processes during movement from the
source region to the surface, or following emplacement. The upper mantle is 91
generally considered to be heterogeneous (Hoffman and Hart, 1978) and although a variety of primary magma compositions are to be expected, several criteria are available for the recognition of primary mantle-derived magmas. These criteria include Mg-number, trace element contents and the presence of high pressure inclusions.
Assuming that primary mantie-derived melts will be in equilibrium with olivine of composition Fogg_90, the primary magmas should have Mg-numbers between 0.69 and 0.73 (e.g. BVSP, 1981; Middlemost, 1985). The range of
Mg-numbers for Ungaran rocks is 0.36 to 0.55 with a mean for all analyses of
0.46 (Table 4-16). These low values indicate that if the magmas were derived from the mantle, they were not primary but must have undergone subsequent fractionation.
Trace element data have also been used to ascertain the primary or derivative nature of basalts from many regions. The elements which have proved to be most useful for this purpose are Ni, Sc and Co. Frey et al. (1978) have determined that
1 to 20% partial melting of mande will produce melts containing 90-670 ppm Ni,
15-28 ppm Sc, and 27-80 ppm Co. Sato (1977) suggested a content of
300-500 ppm Ni for primary Hawaiian basalts whereas Wass (1980) proposed a wider range of Ni contents between 403 and 896 ppm for primary basalts from the
Southern Highlands of New South Wales. A compilation of available data indicates that, although the Ni contents of primary mantle-derived magmas vary from place to place, contents of at least 200-300 ppm are normal (BVSP, 1981).
The Ni contents of Ungaran basalts analysed as part of the present study are below the lower limit for reasonable precision, which as the time of analysis was
50 ppm. These low values are consistent with data from an earlier study which indicated Ni contents between 8 and 24 ppm (Whitford, 1975a). In contrast to the data for Ni, the basaltic lavas from Ungaran contain relatively high contents of Sc
(18-36 ppm) and Co (29-40 ppm) which are consistent with primary mantle derivation. If Ungaran basalts were derived from mantle, their low Ni contents 92
suggest that considerable fractionation of olivine has occurred during passage to the surface.
Finally, the presence of high pressure phases in a lava suggests rapid ascent of the magma to the surface and consequently limited opportunity for crystal fractionation or interaction with the wall-rocks (Frey et al., 1978; Wass, 1980;
Green, 1982). The almost total absence of high pressure phases in Ungaran rocks is consistent with crystal fractionation and/or interaction with the wall rock and suggests that the lavas are not the products of primary mantle-derived magmas
(cf. Nicholls and Ringwood, 1973; Green, 1982).
6.4.2 Fractionation model and major element composition of the primary magma
If Ungaran lavas were produced by fractionation from primary mantle- derived magmas, the composition of these primary magmas can be modelled on the
basis of the observed lava compositions and the compositions of the fractionated
phases (cf. Nicholls and Whitford, 1976; Frey et al., 1978). A major constraint on
this type of modelling is that the primary magma must be in equilibrium with the
fractionating phases.
Modelling was accomplished by the incremental addition of small (0.5
weight %) amounts of olivine until the calculated primary magma was in
equilibrium with olivine of composition Fogg or Fo90. The procedure and an
example of the calculation are listed in Appendix F. In the present calculation a KQ
value of 0.3 is used because the calculated MgO contents of primary magmas from
Java as determined by Nicholls and Whitford (1976) are similar to the olivine-rich
composition used by Roeder and Emslie (1970), who determined a KQ of 0.3.
Tables 6-1 and 6-2 summarize the observed compositions and calculated primary
magma compositions together with the amount of olivine fractionated for all
analysed basalts from Ungaran. The results show that between 16 and 25.5% (by
weight) olivine must be removed from primary magma in equilibrium with olivine
of composition Fo88 to produce the observed lava compositions whereas a primary 93
magma in equilibrium with olivine of composition of Fo90 requires removal of between 23.5 and 33.5% olivine.
Compared to the major element composition used by Roeder and Emslie
(1970; Table 6-3), the calculated primary compositions for Ungaran that are in equilibrium with olivine of composition Fo88_90 have low contents of Si02 and
Ti02 and relatively high contents of A1203 and MgO. The relatively low contents of
Ti02 and high contents of A1203 are typical features of most island arc lavas. If a Kj) = 0.4 is used for the calculation of the composition of the primary magma, higher MgO contents are produced. However, except for their high contents of
K20 (1.1 to 2.3%), and low CaO contents (5.5 to 8.4%), the calculated major element compositions for Ungaran primary magmas (Table 6-3) are similar to the primary magma compositions of Frey et al. (1974) and Langmuir et al. (1977).
The anomalous K20 values possibly result from input from an independent source but the low CaO contents probably reflect fractionation of both olivine and a
Ca-bearing phase such as clinopyroxene. A more realistic model to calculate the primary magma composition can be accomplished by adding both olivine and clinopyroxene to the observed lava compositions. In this study, an olivine/clinopyroxene ratio of 30/70 was chosen because published data for primary magmas with Mg-rich olivine indicate olivine/clinopyroxene ratios of approximately 30/70 (e.g. Barsdell, 1988). The clinopyroxene composition used in the calculation was chosen on the basis of petrographic data for basalts from
Ungaran which indicate a maximum Mg-number of 0.84. Appendix G lists the modelling procedure and an example of the calculation. The results (Table 6-4) show that between 22 and 30% (by weight) of olivine and clinopyroxene must be added to the observed lavas to produce primary magma compositions in equilibrium with olivine of composition Fo88 whereas addition of between 31.5 and 39.5% of the two phases is required to produce primary magma compositions in equilibrium with olivine of composition Fo^. Compared to the model based on fractionation of olivine alone (Table 6-2), this model produces calculated primary 94
magma compositions which have higher CaO, and lower MgO contents
(Table 6-4). Compared to the primary magma compositions of Frey et al. (1974) and Langmuir (1978) listed in Table 6-3, the calculated compositions for Ungaran show remarkable similarity in Si02, Ti02, A1203 and MgO, but have slightiy lower
CaO and higher K20. The calculated primary magma composition from Nicholls and Whitford (1976) has a slightly higher MgO content (Table 6-3).
6.4.3 REE concentration in the primary magma
Rare earth elements are sensitive indicators of many petrogenetic processes and their contents in primary magmas may be modeled from either (a) the compositions of the derivative magma and fractionating phases; or (b) the source composition and degree of partial melting involved. The results of both calculations can then be compared to test the consistency of the models.
Model (a) can be accomplished by using the Rayleigh fractionation equation:
D 1 Cd = CpF( - ), where
C_\ = concentration of element in the derivative,
Cp = concentration of element in the parent, F = weight fraction of derivative, D = bulk distribution coefficient and is given by XiPj, where
X[ = weight fraction of mineral i, and Pj = distribution coefficient for
element j in mineral i. In this study Qj is taken as the observed REE concentration (Table 6-5), F is
the weight fraction of liquid remaining in the calculated primary magma in
equilibrium with olivine of composition Fo90 (Table 6-4), and olivine and
clinopyroxene in the ratio 30/70 are taken as the fractionating phases. The REE
contents of calculated primary magmas for Ungaran are listed in Table 6-6 and
plotted in Figure 6-2 using the normalizing values of Haskin et al. (1968). Gd
values are interpolated from the Sm to Yb join. The distribution coefficients are 95
listed in Appendix H and are taken from Irving (1978), Nicholls and Harris
(1980), and Irving and Frey (1984).
In model (b), fractional fusion and batch melting are the two end-member models for partial melting and the behaviour of REE during both processes can be modelled on the basis of equations derived by Shaw (1970). The objective of this type of modelling is to determine whether a mantle source can produce the calculated primary magmas for Ungaran as listed in Table 6-6 and plotted in
Figure 6-2 (cf. Nicholls, 1981; Carr and Fardy, 1984).
Batch melting is probably the more realistic geologically because it assumes equilibrium between the melt and residual phases. The equation for batch melting may be written as :
Cm/Cs=l/[(D+F(l-P)] where,
Cm = concentration of element in melt,
Cs = concentration of element in source,
D = bulk distribution coefficient and is given by D = XjCj, where
X[= weight fraction of mineral i; and Cj = distribution coefficient of
element j in mineral i,
P = bulk distribution coefficient of minerals entering the melt and is given by P = PiCj, where Pi = fractional contribution of mineral
phase j to the melt,
F = degree of melting.
In the present study, the REE content of the mantle source region was taken as twice that of chondrites (Haskin et al., 1968) and the source compositions and melting proportions are from Nicholls et al. (1980) and Nicholls and Harris
(1980). The distribution coefficients are listed in Appendix H. On the basis of these data, the REE patterns of melts produced by various degrees of partial melting of four upper mande sources comprising eclogite, garnet lherzolite, spinel lherzolite and amphibole lherzolite have been computed (Table 6-7). 96
Comparison of the REE patterns from the batch melting model with the patterns for the primary magma calculated from the Rayleigh fractionation model, indicates that the primary magmas for Ungaran could not have been derived by partial melting of eclogite. The calculated REE pattern for magma produced by batch melting of eclogite (Table 6-7, Fig. 6-3a) is much steeper and more depleted in the HREE than the calculated primary magma REE patterns. The magma produced by between 1 and 10% batch melting would contain only 0.62 to 0.52 times chondrite abundances of HREE (Yb and Lu) whereas it would contain approximately 12 to 37 times chondrite abundances of LREE (La and Ce). A similar argument applies for batch melting of garnet lherzolite (Table 6-7,
Fig. 6-3b). Between 1 and 10% batch melting of garnet lherzolite would produce a magma containing 3.5 to 2.1 times chondrite abundances of HREE which are
significantly lower than those of the calculated primary magma. Very low (< 5%)
degrees of partial melting of garnet lherzolite can produce LREE patterns similar to those of the calculated primary magmas, but as the degree of melting increases
differences between the patterns increase.
Between 5 and 10% batch melting of spinel lherzolite with twice chondritic
REE abundances produces liquids with similar HREE contents to those of the
calculated primary magmas (Table 6-7, Fig. 6-3c). However, the LREE contents
of the magmas produced by batch melting are lower than those of the calculated
primary magma. For 5% melting it is lower by a factor between 0.8 and 2.0 times
chondrite abundance, and between 1.1 and 4.4 times chondrite abundance for 10%
melting. In addition, batch melting of spinel lherzolite produces a flattening of the
REE pattern for elements with atomic numbers between Sm and Lu which is in
contrast to the relative depletion in HREE exhibited by the patterns for the
calculated primary magmas.
Batch melting of amphibole lherzolite produces liquids with similar REE
patterns to those produced by partial melting of spinel lherzolite except that the
flattening of the patterns for MREE and HREE is more pronounced for melting of 97
amphibole lherzolite (Table 6-7, Fig. 6-3d). Liquids derived by batch melting of either amphibole or spinel lherzolite have lower MREE (Sm and Eu) abundances than the calculated primary magmas but the melts derived by partial melting of amphibole lherzolite have lower MREE abundances than the liquids derived from melting of spinel lherzolite. Between 5 and 10% partial melting of amphibole lherzolite with twice chondritic REE abundance produces liquids which are lower in REE than the calculated primary magmas by a factor between 0.8 and 4.6 for
LREE, 1.5 and 2.5 for MREE, and between 0.7 and 1.1 times chondrite abundance for HREE (Table 6-7, Fig. 6-3d).
Comparison between REE patterns for the calculated primary magmas and the proposed mande sources indicates that none of the liquids generated by 1 to
10% melting of the four possible source regions with twice chondritic REE contents match the calculated primary magmas for Ungaran lavas (Table 6-7,
Figs. 6-2 and 6-3). Higher degrees of melting of these sources lower the REE content of the resultant liquid, and therefore, increase differences between the REE patterns for the calculated primary magmas and these liquids. However, if the source region had twice chondritic abundance, the amphibole-bearing assemblages
(i.e. amphibole and spinel lherzolite) appear to be the most likely contenders for the source material of Ungaran rocks.
6.4.4 Degree of partial melting
The batch melting equation of Shaw (1970) may also be used to compute the degree of partial melting of the source required to produce the calculated primary magmas for Ungaran. The large ionic radius and low distribution coefficient (Kp) of incompatible elements makes them suitable for calculations of this type (e.g.
Gast, 1968; Frey et al., 1978). Because K20 is known to have a large ionic size, small Kj) and low concentration in the mantle source, then it is reasonable to assume that all K20 in the mande source is partitioned into the melt, and hence, the batch melting equation can be simplified as Cm/Cs = 1/F. 98
Because the relatively high contents of K20 in the calculated primary magmas for Ungaran imply an enriched source for this element, a K20 content of 0.13% corresponding to a fertile pyrolite mantle (e.g. Green and Ringwood, 1967) has been adopted as the concentration in the source (C.). The simplified batch melting equation indicates that the calculated primary magmas have been derived by between 5 and 13% partial melting (Table 6-4). This range in the degree of partial melting is similar to that postulated by Whitford et al. (1979a) for the generation of high-K calcalkaline rocks in Java. If the potassium content of normal MORB or average pyrolite (0.02%) is used in the calculation, very low degrees of partial melting (1 to 2%) are required to produce the Ungaran primary magmas.
The calculated primary magmas for Ungaran show a wide range of REE patterns (Fig. 6-2) and the variation may possibly be interpreted as resulting from different degrees of partial melting of the same source. However, the batch melting model indicates that the samples with the extreme REE patterns (samples 832 and
326) were produced by very similar degrees of partial melting of fertile pyrolite
(8.96 and 9.32% melting respectively, Table 6-4), and therefore, could not have been derived by different degrees of melting of the same source.
6.4.5 REE concentration in the mantle source
The fact that between 1 and 10% partial melting of four possible mantle assemblages produces magmas with lower REE contents than the calculated primary magmas (Fig. 6-3) implies that the source region has been enriched in these elements. Various authors (e.g. Gill, 1970; Whitford and Nicholls, 1976;
Green, 1980) have proposed that the source region for high-K calcalkaline and shoshonitic magmas is enriched in large ion lithophile elements.
Because the extreme REE patterns from Ungaran primary magma (i.e. samples 832 and 326; Table 6-6; Fig. 6-2) were produced by similar degrees of partial melting (Section 6.4.4), the wide range in LREE contents of the primary magma must be inherited from the source region (i.e. amphibole and/or spinel 99
lherzolite). Thus, sample 326 must be derived from a source more enriched in
LREE than the source for sample 832. The REE abundance in the source may be determined from the batch melting equation (Section 6.4.3) by taking the minimum and maximum REE contents of the calculated primary magma (i.e. samples 832 and 326; Table 6-4; Fig. 6-2) as the composition of the derivative (Cm). The results which are listed in Table 6-8 indicate that production of the calculated primary magma by 5 to 10% melting of eclogite requires a source that is strongly enriched in REE. Relative to chondrite contents the LREE must be enriched 3.2 to
15.1 times, MREE 9.5 to 25.5 times and HREE 36.8 to 49.7 times (Table 6-8;
Fig. 6-4a). The calculated primary magma pattern can be generated by 5 to 10% melting of garnet lherzolite if this source is enriched by 2.0 to 12.2 times chondrite abundance for LREE, 2.6 to 7.7 times chondrite abundance for MREE, and 10.8 to 16.3 times chondrite abundance for HREE (Table 6-8; Fig. 6-4b).
A model based on 5 to 10% melting of spinel lherzolite which contains 2.1 to
12.3 times chondrite abundance for LREE, 2.0 to 6.6 times chondrite abundance for MREE, and 1.6 to 2.5 times chondrite abundance for HREE can produce
liquids with the REE pattern of the calculated primary magma (Table 6-8;
Fig. 6-4c). The calculated primary magma pattern can be generated by 5 to 10%
melting of amphibole lherzolite only if the source region is enriched in LREE at 2.5
to 13.8 times chondrite abundance, 2.9 to 8.4 times chondrite abundance for
MREE, and 2.1 to 3.0 times chondrite abundance for HREE (Table 6-8,
Fig. 6-4d).
On the basis of these results, production of Ungaran basaltic magmas from
garnet-bearing sources (i.e. eclogite and garnet lherzolite) appears to be precluded
unless the source is strongly enriched in LREE and HREE. The unrealistically high
enrichment in HREE for an eclogite precludes it as a possible source material. The
magnitude of enrichment of HREE for a garnet lherzolite source is slightly high compared to the amount of enrichment of HREE observed in mantle-derived rocks
(i.e. up to 5 times chondrite abundance; Frey, 1984). 100
Spinel lherzolite and amphibole lherzolite, with weak to medium enrichment of LREE (2.1 to 13.8 times chondrite contents, Table 6-8), are probable sources.
This amount of enrichment in LREE is not uncommon as LREE contents in the upper mande can be enriched up to 25 times chondrite abundance (cf. Frey, 1984).
HREE levels are only slightly above chondrite contents, at 1.6 to 3.0 times chondrite abundance. This HREE concentration does not necessitate any enrichment processes in the mantle because the REE content of this region is commonly regarded as being twice that of chondrites (e.g. Haskin et al., 1968).
This indicates that both spinel and amphibole lherzolite are possible as a source material for Ungaran primary magma and that these sources do not require enrichment in the HREE.
6.5 Model for magma genesis
6.5.1 MORB- and OIB-type sources
The MORB-type or OIB-type nature of the source material for basaltic rocks has been the subject of debate for many years (e.g. Schilling, 1973; O'Hara,
1973). In the MORB-type model many of the incompatible element ratios and isotopic characteristics of island arc magmas are determined largely by the input of a sedimentary component (e.g. Armstrong, 1971). Wood et al. (1979) and
Saunders et al. (1980) have proposed a model in which basalts from island arcs are generated from a mande veined with an enriched and variable component from the subducted slab. According to their model the veining process (1 to 5% veins) would cause a progressive enrichment in LILE from N- to E-type MORB.
Furthermore, on the basis of trace element and Sr, Nd, Pb and O isotopic data,
Perfitt et al. (1980) concluded that a variety of primitive island arc basalts are generated by adding at least one, and often two or three components (melted oceanic crust with, or without sediments or volatile components) to mantle with
N-type MORB characteristics. This proposal was supported by Tatsumi et al.
(1986) who assumed that mantle material in subduction zones is similar to the 101
source for N-type MORB before the subduction event took place and the enrichment of LILE in island arc basalts is caused by addition of a fluid phase
derived from the oceanic crust. In contrast to the MORB-type source model, and
prompted by the overlap in Sr isotopic compositions in island arcs and OEB,
Morris and Hart (1983) proposed that arc magmas are drawn primarily from an
enriched (relative to MORB) mande wedge. According to this model, LILE and
isotopic signatures of arc lavas are inherited largely from their mande source region
and the mande wedge beneath island arcs is capable of generating a large variety of
magma types, ranging from tholeiitic to enriched alkalic rocks.
On the basis of numerous geochemical and isotopic data (e.g. Frey and
Green 1974; White et al., 1976; Menzies and Murthy, 1980), both the MORB-type
and OIB-type models employ a heterogeneous mantle which is variable, vertically
and horizontally, both on a regional (10-100 km) and small (millimetres to
centimetres) scale. The exact geochemical and isotopic nature of this heterogeneity
and the processes which govern it, however, are poorly understood and
consequendy petrogenetic models proposed by many workers for the generation of
island arc basalts are inconclusive.
Data compiled by Gray (pers. comm., 1988), indicate that lead isotopic ratios
for OIB are much more variable than for MORB (Fig. 6-5). Furthermore, in
subduction zone environments, lavas erupted in regions dominated by oceanic
crust (e.g. Tonga-Kermadec) generally have more restricted and lower Pb-isotopic
values than rocks erupted in regions dominated by continental crust (e.g. Japan,
Cascades, Andes and New Zealand), but some are overlapping (Fig. 6-6). The
207p}-/204pb versus 206Pb/204Pb plot (Fig. 6-7) shows that most samples from
regions dominated by subduction of crust are within the array of OIB rather than
8 the MORB field. In contrast, the 2<> Pb/204Pb versus 206Pb/204Pb pIot (Fig.6 .7)
shows more overlap between these samples and the MORB field. These data
indicate that island arc basalts need not necessarily be derived direcdy from a 102
MORB-type mantle wedge, and support the argument of Morris and Hart (1983) for the existence of an OIB-type source beneath island arcs.
6.5.2 Pb isotopes
Lead isotopes are sensitive indicators for the input of a sedimentary component during magma petrogenesis (Faure, 1986). The results of a study of
Pb-isotopes in 16 lavas from Java Island, including two lavas from Ungaran, have been presented by Whitford et al. (1981). These two samples show slight but significant differences in their isotopic composition with 206Pb/204Pb ratios of
18.759 and 18.858, 207Pb/204Pb ratios of 15.555 and 15.740, and 208Pb/204Pb ratios of 39.049 and 39.264, respectively (Fig. 6-8).
With the exception of some leucititic rocks, lavas from Java are relatively rich
in207 Pb/204Pb compared to MORB and rocks from the Tonga and Mariana Arcs,
but are similar to sediments from near the Tonga and Mariana Trenches (Fig. 6-9).
Compared to rocks from the South Banda Arc (Fig. 6-9) most of the lavas from
Java have similar 207Pb/204Pb ratios but are lower in 206Pb/204Pb.
Whitford et al. (1981) proposed that the relatively high 207Pb/204Pb ratio of
rocks from Java compared to MORB is possibly the result of contamination by a
207Pb-rich component derived from ancient continental crustal material. In this
context the ancient crustal material constitutes the crust beneath the arc or
sediments carried on the slab of subducted oceanic crust. If their argument is true,
the involvement of sediments from the subducted slab is the more probable choice.
Java Island is not underlain by ancient continental crust and rocks of appropriate
compositions are not exposed on this island (Chapter 2). Other geological
evidence, such as the distribution of magmatic arcs accreting towards the Indian
Ocean (Chapter 2), is difficult to reconcile with the existence of ancient continental
crust beneath the present Java Island. Whitford et al. (1981) concluded that the
ancient rocks of the Australian shield may be the source region for sediment
accumulated on the floor of the Indian Ocean and that this sediment may have 103
caused the high 207Pb/204Pb ratios of anomalous calcalkaline rocks in Java.
Although the 207Pb/204Pb ratios of Ungaran are close to the ratios for the anomalous calcalkaline rocks, which indicate sediment involvement (Fig. 6-9), the limited amount of data from Ungaran precludes definitive determination of the role of sediment contamination in the genesis of these rocks. If the high 207Pb/204Pb ratios for rocks from Ungaran are not due to sediment contamination, then they must be inherited from the source region.
With the exception of anomalous calcalkaline lavas, rocks from Java Island are within the mantle array (i.e. OIB; Fig. 6-10), and show no strong evidence of involvement of sediment or subducted upper crustal material. In addition, the low content of 10Be (Tera et al., 1986) in 13 lava samples from Java Island, including one sample of Ungaran, precludes significant input of young sediment. However, input from older sediments (e.g. Cretaceous to Pliocene) must not be discounted due to the short half life of 10Be.
6.5.3 Nd isotopes
Seven lavas from Java Island, including two samples from Ungaran, have been analysed by Whitford et al. (1981) and as shown in Figure 6-11 the rocks from Java have a low and restricted range of 143Nd/144Nd ratios but a relatively wide range of 87Sr/86Sr ratios. These ratios clearly distinguish them from MORB which has higher i^Nd/^Nd (> 0.5130; Carlson et al., 1978) and lower 87Sr/*6Sr ratios. For this reason, Whitford et al. (1981) suggested that the mande beneath
Java Island is not of the MORB-type, but is more radiogenic in Sr. However, the cause of this relative enrichment in radiogenic Sr in Java is unclear. It is not even clear whether prior to the effects of subduction, the mantle in this region had
MORB (Perfitt et al., 1980), OIB (Morris and Hart, 1983), or some other chemical affinity. For example, if prior to the subduction event the mande had a MORB isotopic signature, then all rocks from Java Island which are more radiogenic in Sr and lower in 143Nd/144Nd ratios than MORB are a product of crustal or sediment 104
contamination. On the other hand, if initially the mantle had an OIB isotopic signature, then contamination by altered basaltic crust or sediment is unlikely for the lavas which lie within the mande array (Fig. 6-11). In contrast, the anomalous calcalkaline sample which plots outside the mande array supports the proposal for contamination. This conclusion is supported by comparison of lavas from Java
Island with Banda volcanic rocks which are widely accepted as a prime example of
arc lavas contaminated by sialic sediment (e.g. Whitford and Jezek, 1982).
However, the well defined negative correlation between Nd and Sr isotopic data
for both Java Island and Banda Arc (Fig. 6-11), may reflect heterogeneity in the
mande (cf. De Paolo and Wasserburg, 1976).
6.5.4 Possible causes of Sr isotopic variation in Ungaran
Several possible explanations exist for the variation in the 87Sr/86Sr ratio in
Ungaran lavas. The maximum frequency of occurrence for the 87Sr/86Sr ratio for
MORB samples is for a value of 0.7028 (Morris and Hart, 1983, fig. 7) which is
considerably lower than the observed values for Ungaran (Fig. 4-44). If Ungaran
lavas have come from a MORB-type source then the observed Sr isotopic variation
in Ungaran must be produced by contamination of the primary magma with
strontium derived from subducted oceanic crust incorporating sediment and/or
volatile components, or from assimilation of sialic crustal material immediately
beneath the volcano.
If the relatively high 87Sr/86Sr ratio in rocks from Ungaran has been caused
by contamination of melts from an N-type MORB source with sediments from the
oceanic crust or sialic material beneath the volcano, then the 87Sr/86Sr ratio should
have a positive correlation with Si02, K20, Sr and Rb/Sr (McBirney, 1984). The
87 86 lack of positive correlation between the Sr/ Sr ratios from Ungaran and Si02,
K20 and Sr contents and the Rb/Sr ratio (Figs. 4-42 and 4-43; Table 4-22)
indicates that contamination is not a significant process in the petrogenesis of
Ungaran. Subdivision of the data into two groups based on the SiC_ content 105
does not alter this conclusion. The only significant correlation (at the 95% confidence level) is with Si02 for rocks with less than 53% silica (Table 4-22).
These data support the conclusion of Whitford et al. (1981) who suggested that the mande beneath Java Island is not of the MORB-type. Thus an OIB-type source is the most likely contender for the source region for Ungaran lavas. Irrespective of the mande type, however, the Sr isotopic data are consistent with derivation of at least some basaltic andesites and andesites from basalts by fractionation
(Fig. 4-44).
Several models may explain the observed variations in 87Sr/86Sr ratios if the magmas are derived from an OIB-type source. These include:
1. A disequilibrium melting model (e.g. Whitford, 1975b). In this model decay
of 87Rb to 87Sr is accompanied by a decrease in ionic radius which produces
instability in the mineral lattice and causes the radiogenic Sr to migrate along
grain boundaries and defects into more suitable lattice sites (e.g. Ca).
Because grain boundaries and structural defects are believed to represent
zones that will be the first to breakdown during partial melting, the initial
liquid formed will be enriched in 87Sr. The major criticism of this model is
that isotopic heterogeneity will occur in only small volumes of melt and
the melt must be quickly segregated from the source material to create a
significant difference in the content of radiogenic Sr. However, it is
debatable whether such liquids could escape from the source region. In
addition, Sun (1980) has noted that rapid diffusion would enable isotopic
homogenisation to take place during melting. These limitations suggest that
this model is not a plausible explanation for the isotopic variation in Ungaran
rocks.
2. The primary magmas for Ungaran rocks may come from a source region
where the Rb/Sr ratio varies vertically and/or laterally; thus, the Sr
isotopic ratio of these primary magmas will vary depending on the precise
location of the area of generation of a particular magma Rocks that have low 106
Sr abundances but high 87Sr/86Sr ratios may come from source regions that also have low strontium abundances but high Rb/Sr ratios to generate larger amounts of 87Sr. The observed wide range of 87Sr/86Sr ratios in
Ungaran rocks for a restricted range of Sr contents (Fig. 4-43) suggests that
this model is not satisfactory.
Differences in the mineralogy of the source, the 87Sr/86Sr ratio of these
minerals and the extent of melting can also generate differences in the Sr
isotopic composition. For example, magma produced by differential melting
of Rb-rich (e.g. phlogophite) and Rb-poor mantle phases (cf. O'nions and
Pankhurst, 1974) will produce variation in the Sr isotopic contents. This
model is possibly applicable to basaltic andesites and andesites from
Ungaran because the 87Sr/86Sr ratio has a positive correlation (at the 95%
confidence level) with Rb contents (Table 4-22) but it is not possible for the
basalts which show no significant correlation between 87Sr/86Sr and Rb
(Table 4-22).
According to a model proposed by McCarthy and Cawthorn (1980)
crystallisation in a magma chamber over several million years will produce a
fractionated melt with a high Rb/Sr ratio which will result in the
accumulation of significant radiogenic Sr before eventually crystallizing. This
model assumes that homogenisation due to diffusion does not occur and is
contrary to the assumption that all rocks in a consanguinous igneous complex
have the same initial 87Sr/86Sr ratio. The model does not appear to be
plausible for Ungaran.
A suite of comagmatic igneous rocks will crystallize with the same 87Sr/86Sr
ratio but will have different Rb/Sr ratios. Thus the plot of 87Rb/86Sr versus
87Sr/86Sr for young lavas from a volcano such as Ungaran should define a
horizontal line. The data for Ungaran, however, do not define a horizontal
line (Fig. 6-12) but have considerable scatter which may be interpreted in
several different ways. Various "mande isochrons", including for example, 107
those shown on Figure 6-12, may be drawn. These "isochrons" may reflect
the age of some thermal event in the mande (cf. Cox et al., 1970; Hall,
1986). The scatter in isotopic ratios may be due to mixing or contamination
87 86 but the lack of correlation between the Sr/ Sr ratio and contents of Si02,
K20, Sr and Rb/Sr (Table 4-22; Figs. 4-42 and 4-43) makes these possibilities unlikely.
6. The simplest and probably most likely explanation for the variation is the Sr
isotopic ratios for lavas from Ungaran is heterogeneity in the mande source.
6.5.5 Mantle metasomatism
Several recent studies have proposed a mechanism for mantle metasomatism involving the mixture of at least two geochemically distinct and genetically unrelated components from mande peridotite (e.g. Frey, 1984). One component
(A) represents the bulk of the peridotite and determines the majority of the mineralogy, together with the major element and HREE content. The other component (B) forms only a small portion of the peridotite but controls the abundance of incompatible elements, and is incorporated into minerals such as amphibole. Component B is interpreted as a migratory fluid which is unrelated to component A prior to its infiltration and mixing with the peridotite.
Mantle metasomatism has been invoked in many region to explain the occurrence of enrichment in LREE in amphiboles (e.g. 80 to 2000 times chondrite abundance; Wass and Rogers, 1980). If the process does occur in subduction environments, the long-term production of enriched magmas does present some problems. In particular, enrichment in the mantle wedge prior to subduction is unlikely to sustain generation of magmas of appropriate compositions for a sufficient period of time. Alternatively, the second component could migrate through the slab during the subduction process or, as is more likely, the component is progressively convected into the mantle wedge. In the case of
Ungaran, this process could explain the marked relative LREE enrichment in the 108
source region for some lavas (e.g. sample 326; La up to 13.8 times chondrite abundance; Table 6-8) which may have resulted from migration of a hydrous liquid
(component B) which precipitated as amphibole, and formed an incompatible element enriched region in the upper mande.
6.5.6 Model for HFSE depletion and LILE enrichment
Although the precise nature of the mantle source is debatable (Section 6.5.1), many petrologists believe that the source region for island arc basalts is enriched in incompatible elements (e.g. Arculus and Powell, 1986). Ungaran basalts are enriched in incompatible elements compared to MORB and the source for MORB
(Fig. 6-13). The rocks from Ungaran are also characterized by marked depletion in high field strength elements (HFSE; Nb, Ta, Ti, Hf and Zr) relative to other elements. Depletion of Ta, Nb and Ti (TNT) in island arc basalts relative to
N-MORB has been attributed by Arculus and Powell (1986) to residual Ti-rich phases including sphene and rutile. This explanation, however, is considered to be unlikely. Sphene and rutile have been shown to be stable at pressures up to 20 Kb in hydrous tholeiitic basalt (Hellman and Green, 1979), but this cannot be extrapolated to peridotite compositions or higher pressures where melting is presumed to occur. Fractionation of sphene from primary magma may account for the depletion of HFSE but this is not considered likely due to the profound effects this would have on REE patterns. Ryerson and Watson (1987) have show that to be saturated with a Ti-rich phase (e.g. rutile), a basaltic liquid requires between
7 and 9% Ti02. This means that the depletion of TNT elements in island arc basalts is not controlled by a residual Ti-rich phase in the source region but must be inherited from the source region. It is suggested here, that the relative depletion in
HFSE in Ungaran lavas is more likely due to a process of incompatible enrichment rather than depletion of HFSE.
A mechanism commonly proposed for the enrichment of LILE in magmas is the process of zone refining (Harris, 1957). In this model, incompatible elements 109
preferentially migrate from the solid mande into a partial melt as the melt slowly moves through the mande. Such a mechanism appears to be applicable to virtually every case where enrichment in LILE is required and it is a possibility for Ungaran.
Gill (1972) has suggested that in areas where a Benioff Zone is present, addition of a fluid phase from the subducted slab contaminates the overlying mande wedge which then becomes the source region for island arc magmas. This type of model has subsequently been developed by many workers (e.g. Nicholls and Ringwood, 1973; Green, 1980; Tatsumi et al., 1986). In the model, partial melting of subducted eclogitic oceanic crust produces fluid enriched in incompatible elements. Due to the density contrast between this fluid (S.G. = 2.4
to 2.9; Carmichael et al., 1974) and the residual refractory eclogite (S.G. = 3.4 to
3.5; Ringwood, 1982), the fluid phase formed in the subducted oceanic crust will
rise and react with the overlying mantle wedge. This process enriches the mantle
wedge in water, Si, Al, Na, K and related elements, while depleting the wedge in
Fe and Mg (Ringwood, 1974). The subsequent partial melting of the contaminated hydrous mande then produces the parental magmas of the calcalkaline rock suite
characteristic of many island arcs. This model has been invoked in many area such as the Andes (Dostal et al., 1977), New Guinea (Johnson et al., 1978) and Southern Latium (Civetta et al., 1981). Additional support for this model has been
provided by an experimental study of the dehydration process and the manner of
fluid migration into the overlying mande, which indicates that elements with large
ionic radii are preferentially transported by the fluid phase (Tatsumi et al., 1986).
The release of a fluid phase via dehydration or partial melting of the subducted slab may be a significant process in enriching the mantle beneath Ungaran without
influencing the concentration of HFSE. Small degrees of partial melting of this
mande will consequendy generate rocks with high LILE contents. 110
Calculations based on the mixing equation for two component systems can be used to evaluate the plausibility of a mixing model involving introduction of a
LILE-enriched fluid into the mande wedge. The method used in this thesis follows the approach adopted by Langmuir et al. (1978) who developed a general mixing equation for two component systems. The mixing curve derived from the equation is an hyperbola whose curvature depends on the relative concentrations of the two end members and the type of plot considered (i.e. ratio-ratio, ratio-element or element-element). A mixing curve for each type of plot was calculated through any two typical data points which are well separated. The plausability of the mixing curve was tested by the linearity of a companion plot which was constructed by plotting one of the original ratios versus the ratio of the denominators of the original ratios (Langmuir et al., 1978). The advantage of this
approach is that the compositions of possible end members (e.g. fluid and mantle)
are not required to calculate the mixing curves. Indeed, constraints on the
compositions of the end members are provided by the asymptotes and intercepts
on the hyperbolic plots or the intercepts of the companion plots. In order to avoid
complications due to fractionation, only samples containing less than 52% Si02
were used in the calculations.
The calculated mixing curves and their companion plots (Figs. 6-14 to 6-20)
illustrate several important features including:
1. Most samples lie fairly close to the mixing curve in the plot of Rb/K versus
Rb (Fig. 6-14a). The companion plot (Fig. 6-14b) shows a reasonably good
linear correlation with the major exception of one sample. Similarly, Figure
6-15 indicates that although the data have some scatter, most samples show a
fairly good fit to the mixing curve. The intercept on the companion plot
(Fig. 6-15b) shows that one end member has a maximum 87Sr/86Sr ratio of
approximately 0.7055' Ill
2. The data illustrated on Figure 6-16 are inconsistent with two component
mixing because the mixing curve calculated from one pair of data points is not
the same as the mixing curve calculated from another pair of data points. In 0*7 oz: contrast, plots of Srr Sr versus REE ratios or contents (Figs. 6-16 to 6-
18) show a fairly good fit of the data to the mixing curves and these plots
indicate that one end member has maximum Srr Sr ratio of approximately
0.7054.
3. Plots of 87Sr/86Sr versus both Zr/Y and Zr/Nb (Figs. 6-19 and 6-20) also
show reasonable fits of the data to the mixing curves and indicate a maximum
Srr Sr ratio of approximately 0.7056 for one end member.
4. Although the plots show that it is possible to pass curves through the
available data, the pairs of data points used to construct the curves are not
consistent.
The inconsistency of the pairs of data points used to construct mixing curves together with the scatter observed on some plots indicates that either two component mixing is not a plausible model for the derivation of the Ungaran basalts or, if mixing did occur, at least one end member is heterogenous. The latter alternative is consistent with the model involving a heterogenous mantle wedge (Section 6.4.4).
If the model of fluid contamination of the mantle wedge is applicable to
Ungaran, the major possibilities for the source of the fluid are the subducted oceanic crust (i.e. the crust of the eastern Indian Ocean) or mantle metasomatism.
The former model may be evaluated, at least semiquantitatively, from the geochemical data for Ungaran and the crust of the eastern Indian Ocean but lack of precise data precludes evaluation of the model involving mantle metasomatism.
Site 260 (DSDP Leg 27) is situated approximately 1000 km south of
Ungaran and provided samples offresh, low potassium, quartz-normative tholeiite 112
(Robinson and Whitford, 1974). Assuming that this material is representative of the oceanic crust subducted beneath Ungaran, and assuming that isotopic fractionation does not occur during production of a fluid from this subducted crust, the 87Sr/86Sr ratio of the basalt (0.70433; Whitford, 1975a) is consistent
with the isotopic characteristics of the fluid required by the mixing curves. In
addition, the ratio is suff-cientiy low to permit input from small (< 2%) amounts of
sediment and/or sea water (Fig. 6-21). The basalt from Site 260 has similar contents of HFSE to Ungaran basalts
but it is relatively depleted in LILE (Fig. 6-13). This is consistent with
experimental data which indicate that fluids derived from a subducted slab should
preferentially transport elements with large ionic radii (Tatsumi et al., 1986). Thus
mixing of this type of fluid with a heterogeneous OIB-type mantle would provide a
source with geochemical characteristics suitable for the generation of the lavas
erupted from Ungaran.
6.6 Summary
Geochemical data indicate that the mantle is the most plausible source region
for lavas from Ungaran. Modelling on the basis of major element contents of
basalt lavas indicates that addition of between 22 and 30%, and 31.5 and 39.5%
olivine and clinopyroxene (in the ratio 30/70) is required to produce primary
magmas in equilibrium with olivine of compositions Fo88 and Fo90 respectively.
The K2Q contents of the calculated primary magmas indicate between 5 and 13% partial melting of the source and also indicate that the two samples with the
extreme REE patterns can be derived by similar degrees of partial melting.
Modelling on the basis of REE data suggests that amphibole or spinel lherzolite
enriched in LREE is the most probable source composition for lavas from Ungaran. 113
Several alternative explanations have been proposed to account for the observed major element, trace element and isotopic variations in Ungaran. Derivation of Ungaran lavas from a MORB-type source requires contamination with sediments from the oceanic crust or with sialic material from beneath
Ungaran. Lack of positive correlation between ^Sr/^Sr ratios and Si02, K20, Sr and Rb/Sr precludes this possibility. An OIB-type source is more plausible and possible explanations for the observed geochemical variations include vertical and lateral variation of Rb/Sr ratio in the source region, mineralogy heterogeneity in the mantle, heterogeneity in the magma chamber due to fractionation, and disequilibrium melting. However, no unique explanation has emerged, and a general model of mantle heterogeneity has been invoked to explain the observed variations in lavas from Ungaran.
The inconsistency of the pairs of data points used to construct the mixing curves may indicate that a model of mixing a LDLE-enriched fluid with the mantle wedge is not plausible. The scatter observed in all plots may also be due to heterogeneity in at least one end-member (e.g. the mantle wedge). If the model of fluid contamination of an heterogenous mande wedge is applicable to Ungaran the major possibilities for the source of the fluid are the subducted oceanic crust (i.e. the crust of the eastern Indian Ocean) or from mantle metasomatism. The former model may be evaluated, at least semiquantitatively, from the geochemical data for
Ungaran and the crust of the eastern Indian Ocean but lack of precise data precludes evaluation of the model involving mande metasomatism
Assuming that basalt from DSDP Leg 27, Site 260 is representative of the oceanic crust subducted beneath Ungaran, and assuming that isotopic fractionation does not occur during production of a fluid from this subducted crust, the ^Sr/^Sr ratio of the basalt (0.70433) is consistent with the isotopic composition of the fluid required by the mixing curves.The ratio is sufficiently low to permit 114
input from small (< 2%) amounts of sediment and/or sea water (Fig. 6-21).
Furthermore, the modelled Srr Sr ratio of the mande wedge is well within the
range of values for the 87Sr/86Sr ratio of OIB-type mantle (Hoffman and Hart,
1978). Comparison between contents of HFSE and LILE in Ungaran basalts and the crust of the eastern Indian Ocean suggests that the model involving derivation of Ungaran lavas from a mantle wedge contaminated by a fluid from the subducted slab is plausible. Experimental data indicate that this fluid would incorporate LILE in preference to HFSE and thus account for the relative enrichment of LILE in
Ungaran lavas. Many observed geochemical variations in Ungaran lavas, particularly in Sr/^Sr ratios, reflect heterogeneity in an OIB-type mantle wedge. 115
CHAPTER 7
CONCLUSIONS
7.1 Conclusions
Java Island which forms part of the Sunda Arc, has a relatively simple tectonic and geological setting typical of many island arcs. The island has developed in response to subduction of the northward-moving Indian-Australian Plate beneath the southward-moving Eurasian Plate and has been associated with a series of subduction zones which have migrated with time in response to changes in the tectonic setting of the region.
Ungaran volcano, Central Java, is situated 197 km above a Benioff Zone dipping at 55^, and forms part of the second of three cycles of volcanism recognized on Java Island. The volcano which was active between the Late Pliocene and the Late Pleistocene is characterized by three stages of growth, interrupted by two episodes of cone collapse. The products of eruption can be grouped into four major units comprising Oldest Ungaran, Old Ungaran, Parasitic Cones and Young
Ungaran.
Lavas from Ungaran comprise basalts, basaltic andesites and andesites and have strong similarities in mineralogy and texture. In hand specimen they are dark grey to black, and are porphyritic with either a holocrystalline or hypocrystalline groundmass. Phenocrysts comprise 35% to 66% by volume of the rocks and consist of plagioclase, clinopyroxene, Fe-Ti oxide and amphibole. Mica is a subordinate phase in basaltic andesite and andesite whereas olivine occurs in some samples of basalt and basaltic andesite. Plagioclase and clinopyroxene are the dominant phenocrystic phases. In some specimens, plagioclase comprises up to
33% by volume of the rock. Most phenocrysts show little or no alteration with only minor replacement by chlorite and calcite. The average total phenocryst content of each rock type is very similar (approximately 40%) but the proportion of each phase 116
differs. In particular, the volume of phenocrystic clinopyroxene and Fe-Ti oxide decreases in the series basalt to basaltic andesite to andesite, and the highest contents of amphibole and mica occur in andesite. Porphyritic lavas are either holocrystalline or hypocrystalline. In holocrystalline samples the phenocrysts are set in a fine-grained groundmass of either microlitic or granular feldspar, clinopyroxene and Fe-Ti oxide with pilotaxitic, orthophyric, interstitial or intergranular textures.
Plagioclase is the most abundant phenocrystic phase in all rock types and ranges in composition from oligoclase to anorthite. Thin rims of K-feldspar occur on some phenocrysts of plagioclase. The high An content in normally zoned plagioclase phenocrysts in andesite may indicate some plagioclase accumulation, whereas a bimodal distribution for the plagioclase compositions coupled with coexisting normal, reverse and oscillatory zoning in basaltic andesite may be indicative of magma mixing in the magma reservoir beneath Ungaran. Decreasing
An content of plagioclase with increasing age suggests that the magma beneath
Ungaran became relatively more saturated and alkaline. The groundmass plagioclase in generally less calcic than, or similar in composition to, the phenocrysts.
Clinopyroxene is the only pyroxene in lavas from Ungaran and comprises diopside, augite and salite (most abundant). The composition of clinopyroxene phenocrysts ranges from W043.2En45.5Fs11.3 to Wo56.2En3g.2Fs7.9 and although groundmass compositions are similar for all rock types, the clinopyroxene in andesites is more restricted in composition than the phase in basalts and basaltic andesites. On average, the clinopyroxene phenocrysts in basalt samples are more aluminous and Ti-rich compared with clinopyroxene from basaltic andesites and andesites. The slopes of the regression lines for the distribution of A1IV versus A1VI in clinopyroxene decreases from 15% in basalt through 12.9% in basaltic andesite to 11.1% in andesite. These changes may be attributed to decreasing pressure. In general, the Ti02 and AI2O3 contents of clinopyroxene decrease with increasing 117
time except for lavas from the Parasitic Cones which are anomalous. This decrease is attributed to increasing silica activity in the magma chamber beneath Ungaran.
Magnetite is the only Fe-Ti oxide in all lavas from Ungaran. The absence of ilmenite and low contents of ulvospinel are typical of many island arc lavas and may be correlated with their Ti02-depleted character. The modal content of magnetite decreases in the series from basalt to andesite and reflects the decreasing Ti02 content of the magma.
Most amphibole grains are magnesian-hastingsite and the "black amphibole" is indicative that their decomposition occurs under conditions of rapid cooling at lower pressure. The amphibole from Ungaran is characterized by low numbers of
Ti, Si and A1VI ions. The low Si values are characteristic of island arc hornblendes whereas the low contents of A1VI indicate that these amphiboles formed at pressure less than 9 Kb.
Biotite occurs as a common accessory phase in basaltic andesites and andesites but is absent from basalts. Most of the fresh olivine occurs in lavas from
Old Ungaran and it has a relatively Fe-rich composition (F059 to F079). *n samples from Oldest Ungaran and the Parasitic Cones, the calculated liquid in equilibrium with the observed olivine has lower Mg/Mg+Fe2+ than the total-rocks. The simplest explanation is that some accumulation of olivine has occurred. In lavas from Old and Young Ungaran, the Mg/Mg+Fe2+ values of the total-rocks are within the range for liquids in equilibrium with the observed phenocrysts which suggests that the olivine formed by near-liquidus crystallisation. Olivine xenocrysts in lavas from the Parasitic Cones are too Mg-rich to represent the product of near-liquidus crystallisation from a magma represented by the total-rock composition.
On the basis of M-C diagrams the order of crystallisation of phases in
Ungaran is olivine, plagioclase, clinopyroxene, Fe-Ti oxide, amphibole and mica.
Later appearance of amphibole and mica is controlled by decreasing temperature at low or moderate pressure. The clinopyroxene and amphibole crystallized at pressures less than 9 Kb. Calculated temperatures derived from phenocryst rim 118
compositions of clinopyroxene, which presumably record magmatic temperatures on eruption, show that the basalts have a relatively restricted range in temperature
compared with basaltic andesites and andesites (Table 3-98). Temperatures derived
from amphibole compositions are more variable but generally overlap with
temperatures indicated by pyroxene compositions.
Lavas from Ungaran exhibit a continuum of compositions which range from
48.95% to 60.80% Si02. Compared with most rocks of similar Si02 content, the
lavas from Ungaran are characterized by high contents of A1203 and total alkalies,
high ferric/ferrous iron ratio, high contents of incompatible elements and low MgO
contents. Mafic rocks from Ungaran range from Ne-normative to Q-normative
depending on the ferric/ferrous iron used in the calculation. Most of the basalt
samples, however, are saturated if the assumed ratio of 0.2 for Fe203/FeO+Fe203
is used but all are relatively evolved with a maximum Mg-number of 0.55. The low
Mg-numbers indicate that these basalts crystallized from derivative melts and do not
represent primary, mantie-derived magma.
The distribution of data points on the plot of Sr versus Si02 (Fig. 4-24) may
be interpreted in several different ways. The scatter precludes derivation of all rock
types in a single, simple fractionation model and thus may simply reflect different
sources for different samples. Alternatively, the samples may be related by
fractionation but the scatter necessitates several fractionation series. Figure 4-25
shows that the Sr content of the basalts has a negative correlation with the Ca/Sr
ratio which is consistent with fractionation of calcic plagioclase (cf. Noble and
Korringa, 1974). The correlation between these parameters for either the basaltic
andesites or the andesites, however, is not significant at the 95% confidence level.
In addition, the general decrease in the Ca/Sr ratio in the series basalt to basaltic
andesite to andesite is also consistent with plagioclase fractionation. If plagioclase
fractionation is important in Ungaran rocks, the rocks with higher Sr contents
should reflect plagioclase accumulation which should also be indicated by positive 119
Eu anomalies. The rare occurrence and small magnitude of such anomalies in
Ungaran lavas precludes significant plagioclase fractionation.
The wide range of Rb contents, particularly in basalts (13-81 ppm;
Table 4-17; Fig. 4-26) may indicate more than one liquid line of descent which implies that the lavas have originated from different sources and/or from a single source which has givenrise t o severalfractionation series . The K/Rb ratio in basalts also reflects the relative roles of amphibole and mica in the source region (Green,
1980). Basalts from Ungaran with relatively high Rb contents may have originated from a source with a relatively higher content of amphibole or mica than basalts with lower Rb contents.
Thorium has a significant positive correlation with Si02 (Fig. 4-29;
Table 4-20). Initial lavas within each major stratigraphic unit except Oldest Ungaran are characterized by relatively high thorium contents (Figs. 4-11, 4-15 and 4-20).
Pb concentrations in lavas from Ungaran are extremely high (10 to 33 ppm;
Table 4-16) compared to other high-K calcalkaline and shoshonitic suites and the wide range of Pb contents in basalts may reflect different sources for the magmas.
Alternatively some of the basalts with relatively low Pb contents may be related to the basaltic andesites and andesites by fractionation, but basalts with high Pb contents are unlikely to be related to the other rock types by this process.
Zr in the Ungaran volcanic rocks correlates positively at the 95% confidence level with a variety of elements including Si02, Rb and Hf (Figs. 4-31 to 4-33;
Table 4-20). This positive correlation implies minimal or no zircon fractionation.
Differences in the Zr/Hf ratios for rocks from Ungaran may reflect derivation of the magma from sources with different Zr and Hf contents, or by different degrees of partial melting of a single source, or the effects offractional crystallisation . Nb has a restricted range (Table 4-16) and overall it has significant correlation with several elements including Si02 and Ta (Table 4-20; Figs. 4-35 and 4-36).
In contrast to rubidium, Ti has an antipathetic relationship with potassium
(Table 4-20) and the K/Ti ratio increases with increasing silica content (Fig. 4-37). 120
This pattern of K versus Ti for Ungaran lavas reflects the effect of fractionation of
Fe-Ti oxide and is not consistent with the general pattern across the Sunda-Banda aArc, where Ti shows a positive correlation with K (Wheller et al., 1987). The progression from tholeiitic to leucititic rock suites in the Sunda-Banda Arc is accompanied by an increase in the K/Ti ratio (Wheller et al., 1987). Similarly, the progression from high-K calcalkaline to shoshonitic rocks in Ungaran is also accompanied by an increase in the K/Ti ratio. The decreases in Co, V, Sc and Cr with increasing Si02 accord with fractional crystallisation of olivine, clinopyroxene, plagioclase and Fe-Ti oxide (cf. Wyers and Barton, 1986). Samples which depart markedly from the regression lines defining the relationships between
SiO^ and compatible element contents are probably derived from different sources.
Except for the Parasitic Cones, eruptions from Oldest, Old and Young
Ungaran always commenced with basalt or basaltic andesite and ended with andesitic lavas. In general, temporal variations in the major element geochemistry of lavas from Oldest, Old and Young Ungaran are similar. They increase in Si02 and
K20, and decrease in Ti02, MgO, total FeO and CaO (Section 4.3.1). These variations presumably reflect differences in the magma chamber below Ungaran and several possible models for the production of these variations are proposed including: (a) the magma chamber beneath Ungaran may have been vertically stratified due to crystal fractionation; (b) infrequent influxes of basaltic magma into a shallow magma system and subsequent fractionation to more evolved compositions; (c) frequent influxes of basaltic magma into a shallow magma system; (d) mixing of felsic country rock or silicic magma with basaltic magma; and
(e) different parental magmas.
The first model is viable to explain the eruption products of the Parasitic
Cones whereas the second and third models are viable for Oldest, Old and Young
Ungaran. Except for the existence of a bimodal distribution for plagioclase
compositions in some samples, no petrographic evidence in support of the mixing
model has been found in the present study. In addition, lack of correlation between 121
87 86 Sr/ Sr and Si02, K20 and Sr content, and Rb/Sr ratio (Figs. 4-42 and 4-43) precludes significant mixing. The similarity in 87Sr/S6Sr ratios for some rocks indicate that they may be related by fractionation. However, some samples of basaltic andesite and andesite have significandy lower ratios than the basalts. These data are consistent with the possibility that some basaltic andesites and andesites were derived from more primitive basalts than those exposed on Ungaran, or were derived from different parent material to the other rocks.
On the basis of K20 and Si02 contents (Fig. 4-1), most of the basalts are shoshonites whereas most of the basaltic andesites and all andesites are high-K calcalkaline. In term of magmatic evolution, the shoshonitic rocks dominated the early stages of magmatic activity in Ungaran whereas high-K calcalkaline rocks were produced during later stages. More evolved rock types are developed in the high-K calcalkaline suite than in the shoshonite suite.
Detailed inspection of geochemical data of rocks from Ungaran indicate that the shoshonitic rocks from Ungaran (Table 5-2) have lower contents of Si02,
Na20, K20, and lower amounts of incompatible elements including Rb, Zr, Nb,
Pb, Th,Y, Hf, Ba, Zr and Ta than high-K calcalkaline rocks (Table 5-3). In contrast, the shoshonitic rocks from Ungaran have higher average contents of
Ti02, total FeO, MgO and P205 (Table 5-2) than the high-K calcalkaline rocks
(Table 5-3). Furthermore, by using the analysed ferric/ferrous ratio, the shoshonitic mafic rocks from Ungaran range from Ne-normative to Q-normative but the high-K calcalkaline rocks are Ol-normative to Q-normative (Fig. 5-1). In the AFM and Na20-CaO-K20 plots the shoshonitic rocks show a more restricted range of compositions than the high-K calcalkaline rocks (Fig. 5-3). Comparison of geochemical data for shoshonitic and high-K calcalkaline rocks from various tectonic and geographic regions shows that the rocks of each association form a coherent group, and that most of the Ungaran rocks fall near the middle of the range of values from these regions. 122
Geochemical data indicate that the mantle is the most plausible source region for lavas from Ungaran. Modelling on the basis of major element chemistry indicates that the most mafic lavas from Ungaran can be generated from the calculated primary magma by fractionation of between 16 and 25.5% olivine of composition Fogg or by fractionation of between 23.5 and 33.5% olivine of composition F090. However, the calculated primary magmas for Ungaran that are in equilibrium with olivine of composition Fogg.90 ^ave slightly lower contents of
CaO compared to primary magmas from elsewhere. A more realistic model to calculate the primary magma composition can be accomplished by adding both olivine and clinopyroxene to the observed lava composition. The results show that addition of between 22 and 30%, and 31.5 and 39.5% olivine and clinopyroxene
(in a ratio 30/70) is required to produce primary magmas in equilibrium with olivine of compositions Foss and F090 respectively. Compared to the model based on fractionation of olivine alone, this model produces calculated primary magma compositions which are similar to primary magmas from elsewhere.
The rocks from Ungaran are characterized by enrichment in LREE (LaN =
54.2 to 155.5), moderatefractionation of REE (LaN/YbN = 4.4 to 16.9) and most samples have slight negative Eu anomalies (Eu/Eu* = 0.76 to 0.95). Negative Eu anomalies are normally interpreted as resulting from removal of plagioclase and the relatively small magnitude of these anomalies in rocks from Ungaran implies that plagioclasefractionation i s not a major mechanism in the petrogenesis of these rocks.
The calculated primary magmas for Ungaran show a wide range of REE patterns (Fig. 6-2) and the variation may be possibly interpreted as resulting from different degrees of partial melting of the same source or from fractionation process. The K20 contents of the calculated primary magmas indicate between
5 and 13% partial melting of the source and also indicate that the two samples with the extreme REE patterns resulted from similar degrees of partial melting, and therefore, these samples could not have been derived by different degrees of 123
melting of the same source. Modelling on the basis of REE data suggests that amphibole or spinel lherzolite enriched in LREE (2.1 to 13.8 times chondrite contents, Table 6-7) is the most probable source composition for lavas from
Ungaran. Production of primary magmas from garnet-bearing sources (i.e. eclogite and garnet lherzolite) appears to be precluded unless the source region is extremely enriched in LREE and HREE.
Several alternative explanations have been proposed to account for the observed major element, trace element and isotopic variations in Ungaran.
Derivation of Ungaran lavas from a MORB-type source requires contamination with sediments from the oceanic crust or with sialic material beneath Ungaran. Rocks from Ungaran are within the mantle array (OIB-type source). Substantial involvement of sediment or subducted upper crustal material is precluded by the Pb,
Nd and Be isotopic data.
Significant differences exist in the Sr isotopic ratios for lavas from Ungaran.
The most important features of these isotopic data comprise:
1. Rocks with less than 53% Si02 (essentially basalts) have a wide range
of 87Sr/86Sr ratios and a mean of 0.70503 whereas rocks with greater
than 53% Si02 (basaltic andesites and andesites) have a more restricted
range of values and a mean of 0.70489. These two groups are well
defined for the relationship of the ^Sr/^Sr ratio to some other major
element oxides (e.g. FeO, MgO, K2O, Ti02 and CaO) but are not
apparent on the plots of the isotopic ratio versus AI2O3, Na20, Sr or
Rb/Sr (Figs. 4-42 and 4-43)
2. The 87Sr/86Sr does not correlate with major or trace element data when
all samples are considered (Table 4-22).
3. Si02, MgO, CaO and Ti02 have significant (95% confidence level)
87 g correlation with Sr/ 6Sr for rocks with < 53% Si02 whereas Al203,
FeO, Na20 and Rb show significant correlation for samples with > 53%
SiC_. 124
4. There is no consistent variation between 87Sr/86Sr and time (Fig. 4-44).
5. The 87Sr/86Sr ratio for rocks from Ungaran is relatively high compared
with the calcalkaline and leucititic rocks from Java (Fig. 4-45).
The Sr isotopic data from Ungaran indicate that derivation of Ungaran lavas from a MORB-type source requires contamination with sediments from the oceanic crust or with sialic material from beneath Ungaran. Lack of positive correlation
87 86 between Sr/ Sr ratios and Si02, K20, Sr and Rb/Sr precludes this possibility.
An OIB-type source is more plausible and possible explanations for the observed geochemical variations include vertical and lateral variation of Rb/Sr in the source region, mineralogy heterogeneity in the mantle, heterogeneity in the magma chamber due to fractionation, and disequilibrium melting. However, no unique explanation has emerged, and a general model of mantle heterogeneity has been invoked to explain the observed variations in lavas from Ungaran.
Rocks from Ungaran are characterized by marked depletion in contents of
high field strength elements (HFSE; Nb, Ta, Ti, Hf and Zr) relative to LILE. The
marked depletion of Ta, Nb and Ti (Fig. 6-13) relative to other elements cannot be
related to residual Ti-rich phases because although these phases are stable at
pressures up to 20 Kb in hydrous tholeiitic basalt, this cannot be extrapolated to
peridotite compositions or higher pressures where melting is presumed to occur.
Furthermore, to be saturated with a Ti-rich phase (e.g. rutile), a basaltic liquid
requires between 7 and 9% Ti02. This means that the deletion in Ta, Nb and Ti in
island arc basalts is not controlled by a residual Ti-rich phase but must be inherited
from the source region. Thus the relative depletion in HFSE in Ungaran lavas is
more likely due to a marked enrichment of incompatible elements rather than
depletion of HFSE.
The mechanisms commonly proposed for the enrichment of LILE in source
regions for high-K calcalkaline and shoshonitic rocks include zone refining and
contamination by a fluid phase. The process of zone refining appears to be 125
applicable to almost every case where enrichment in LILE is required and it is a
possibility for Ungaran.
The inconsistency of the pairs of data points used to construct mixing curves may indicate that a model of mixing a LILE-enriched fluid with the mande wedge is not plausible. The observed scatter may also be due to heterogeneity in the mande wedge. If the model of fluid contamination of the mantle wedge is applicable to
Ungaran, the major possibilities for the source of the fluid are the subducted oceanic crust or from mande metasomatism. The former model may be evaluated, at least semiquantitatively, from the geochemical data for Ungaran and the crust of the eastern Indian Ocean, but lack of precise data precludes evaluation of the model involving mande metasomatism. Assuming that basalt from DSDP Leg 27, Site
260 which is situated approximately 1000 km south of Ungaran, is representative of the oceanic crust subducted beneath Ungaran, and assuming that isotopic fractionation does not occur during production of a fluid from the subducted crust, the 87Sr/86Sr ratio of the basalt is consistent with the isotopic characteristics of the fluid required by the mixing curves. The Sr isotopic ratio is sufficientiy low to permit minor input (< 2%) from sediment and/or sea water.
Comparison between contents of HFSE and LILE in Ungaran basalts and the
crust of the eastern Indian Ocean suggests that the model involving derivation of
Ungaran lavas from a mantle wedge contaminated by a fluid from the subducted
slab is plausible. Experimental data indicate that this fluid would incorporate LILE
in preference to HFSE and thus account for the relative enrichment of LILE in
Ungaran lavas. Many observed geochemical variations in Ungaran lavas,
particularly in ^Sr/^Sr ratios, reflect heterogeneity in an OIB-type mande wedge. 126 127
REFERENCES:
ALLEN J.C. and BOETTCHER A.C. 1978. Amphiboles in andesite and basalt: U.
Stability as a function of P - T- fH20 -f02. American Mineralogist 64, 1074-
1087.
ANDO S. 1975. Minor element geochemistry of the rocks from Mashu Volcano,
eastern Hokkaido. Hokkaido University. Faculty of Science, Journal series 4
16, 553-566.
AOKI K. and KUSHIRO I. 1968. Some clinopyroxene from ultramafic inclusions
in Dreiser Weiher, Eifel. Contributions to Mineralogy and Petrology 18, 326-
337.
ARCULUS R.J. and JOHNSON R.W. 1981. Island arc magma sources: a
geochemical assessment of the role of slab derived component and crustal
contamination. Geochemical Journal 15,109-133.
ARCULUS R.J. and POWELL R. 1986. Source component mixing in the regions
of arc magma generation. Journal of Geophysical Research 91, 5913-5926.
ARMSTRONG R.L. 1971. Isotopic and chemical constraints on models of magma
genesis in volcanic arcs. Earth and Planetary Science Letters 12, 137-142.
ASIKIN S. 1974. Evolusi geologi Jawa Tengah dan sekitarnya, ditinjau dari segi
tektonik dunia yang baru. Unpublished Ph.D thesis. Institute of Technology
of Bandung, Indonesia.
BAHAR I. 1984. Contribution a la connaissance du volcanisme Indonesien: Le
Merapi (Central Java), cadre sructural, petrologie, geochimie et implications
volcanologiques. Academic De Montpellier, 212 pp.
BAHAR 1. and GIROD M. 1983. Controle structural du volcanisme Indonesien
(Sumatra, Java-Bali); application et critique de la method de Nakamura.
Bulletin de la Societe geologique de France 67,1-4. 128
BAKER B.H. 1978. A note on the behaviour of incompatible trace elements in
alkaline magmas. In: Neuman E.R. and Ramberg LB. eds. Petrology and
geochemistry of continental rifts, pp. 15-25. Reidel D. Publishing Company,
Dordrecht.
BAKER P.E. 1968. Comparative volcanology and petrology of the Atlantic.
Bulletin Volcanologique 32, 189-206
BARBERI F., INNOCENTI F., FERRARA G„ KELLER J. and VILLARI L.
1974. Evolution of Eolian arc volcanism (southern Tyrrhenian Sea). Earth and
Planetary Science Letters 21, 269-276.
BARSDELL M. 1988. Petrology and petrogenesis of clinopyroxene-rich tholeiitic
lavas, Merelava volcano, Vanuatu. Submitted to Journal of Petrology.
BASALTIC VOLCANISM STUDY PROJECT (BVSP). 1981. Basaltic volcanism
on the Terrestrial Planets. Pergamon Press, Inc., New York, USA.
BATAN - NIRA. 1978. Nuclear Site Surveys. Unpublished final volcanological
report. Project. PLTN - ITALINDO, 95 pp.
BECK E.H. and LEHNER I. 1974. Oceans, new frontier in exploration. American
Association of Petroleum Geologists, Bulletin 58, 376-395.
BELLIENI G., COMIN-CHIARAMONTI P., MARQUES L.S., MELFI A.J.,
NARDI A.J.R., PAPATRECHAS C, PICCIRILLO E.M., ROISENBERG
A. and STOLFA D. 1986. Petrogenetic aspects of acid and basaltic lavas from
the Parana Plateau (Brazil): geological, mineralogical and petrochemical
relationships. Journal of Petrology 27, 915-944.
BEMMELEN R.W. van. 1941. Geologische kaart van Java, toelichting bij de
bladen 73 (Semarang) en 74 (Oengaran). Dienst van den Mijnbouw in
Nederlandsch, Indie, Batavie, Geol. map and description, 115 p.
BEMMELEN R.W. van. 1949. The Geology of Indonesia, 2nd Edition, 1.
Martinus Nijhoff. 129
BEN-AVRAHAM Z. and EMERY K.O. 1973. Structural framework of Sunda
Shelf. American Association of Petroleum Geologists, Bulletin 57,
2323-2366.
BENDER J.F., HODGES F.N. and BENCE A.E. 1978. Petrogenesis of basalts
from the project FAMOUS area: experimental studyfrom 0 to 15 kbars. Earth
and Planetary Science Letters 41, 277-302.
BOCCALETTI M., MANETTI P., PECCERILLO A. and VASS1LEVA S.G.
1978. Late Cretaceous high-potassium volcanism in eastern Srednogrie,
Bulgaria. Geological Society of America Bulletin 89, 439-447.
BOETTCHER A.L. 1977. The role of amphibole and water in circum-Pacific
volcanism. In: Maxwell A.E., ed. The Sea, pp. 445-464. Wiley-Interscience,
New York.
BOHLEN S.R., WALL V.J. and BOETTCHER A.L. 1983. Experimental
investigations and geological applications of equilibria in the system
FeO - Ti02 - AI2O3 - Si02 - H2O. American Mineralogist 68,1049-1058.
BOLLIGER W. and de RUITER P.A.C. 1976. Geology of the south central Java
offshore area. Indonesian Petroleum Association, 4th Annual Convention,
Proceedings 1, 67-81.
BOWEN D.G. 1978. Quaternary geology: a stratigraphic framework for
multidisciplinary work. Oxford, Pergamon Press.
BOWIN C, PURDY G.M., JOHNSTON C, SHOR G., LAWVER L.,
HARTONO H.M.S. and JEZEK P. 1980. Arc-continent collision in Banda
Sea region. American Association of Petrology and Geology, Bulletin 64,
868-915
BROPHY J.G. and MARSH B.D. 1986. On the origin of high-alumina arc basalt
and the mechanics of melt extraction. Journal of Petrology 27,763-789.
BUDDINGTON A.F. and LINDSLEY D.H. 1964. Iron-titanium oxide minerals
and synthetic equivalents. Journal of Petrology 5, 310-357. 130
CARLSON R.W., MACDOUGALL J.C. and LUGMAIR G.W. 1978. Differential
Sm/Nd evolution in oceanic basalts. Geophysical Research Letters 5,
229-232.
CARMICHAEL I.S.E. 1967. The iron-titanium oxides of salic volcanic rocks and
their associated ferromagnesian silicates. Contributions to Mineralogy and
Petrology 14, 36-64.
CARMICHAEL I.S.E., TURNER F.J. and VERHOOGEN J. 1974. Igneous
Petrology. McGraw-Hil.
CARR P.F. 1984. The Late Permian shoshonitic province of the southern Sydney
Basin. Unpublished PhD thesis, Wollongong University.
CARR P.F. and FARDY J.J. 1984. REE geochemistry of Late Permian
shoshonitic lavas from the Sydney Basin, New South Wales, Australia.
Chemical Geology 43, 187-201.
CAS R.A.F. and WRIGHT J.V. 1987. Volcanic successions: modern and ancient:
a geological approach to processes, products and successions. Allen and
Unwin Inc., London.
CHAYES F. 1964. Variance-covariance relations in some published Harker
diagrams of volcanic suites. Journal of Petrology 5, 219-237.
CIVETTA L., INNOCENTI F., PECCERILLO A. and POLI G. 1981.
Geochemical characteristics of potassium volcanics from Mts. Ernici
(southern Latium, Italy). Contributions to Mineralogy and Petrology 78,
37-47.
COHEN R.S. and O'NIONS R.K 1982. Identification of recycled continental
material in the mande from Sr, Nd and Pb isotope investigations. Earth and
Planetary Science Letters 61,73-84.
COHEN R.S., EVENSEN N.M., HAMILTON P.J. and O'NIONS R.K. 1980.
U-Pb, Sm-Nd, and Rb-Sr systematics of mid-oceanridge basalt glasses.
Nature 283, 149. 131
CONDON W.H., PARDYANTO L. and KETNER K.B. 1975. Geologic map of
the Banjarnegara and Pekalongan Quadrangles, Java. Geological Survey of
Indonesia, Scale 1:100,000.
CONEY P.J. and REYNOLDS S.J. 1977. Cordilleran Benioff Zones. Nature 270,
403-406.
COX A. 1969. Geomagnetic reversals. Science 163, 237-245.
COX KG., GASS I.G. and MALLICK D.I.J. 1970. The peralkaline volcanic
suite of Aden and Little Aden, south Arabia. Journal of Petrology 11,
433-462.
CRAWFORD A.J., FALLOON TJ. and EGGINS S. 1987. The origin of island
arc high-alumina basalts. Contributions to Mineralogy and Petrology 97,
417-430.
CUMMINGS D. and SCHILLER, G.I. 1971. Isopach map of the Earth's crust.
Earth Science Reviews 7, 97-125.
CURRAY J.R., SHOR G.G., RAITT R.W. and HENRY M. 1977. Seismic
refraction and reflection studies of crustal structure of the eastern Sunda and
western Banda Arcs. Journal of Geophysical Research 82,2479-2489.
DALRYMPLE G.B. 1972. Potassium-Argon dating of geomagnetic reversal and
North American glaciation. In: Bishop W.W. and Miller J.A. eds. Calibration
of hominoid evolution, pp. 107-134, Edinburgh.
DAVIDSON J.P. 1986. Isotopic and trace element constraints on the petrogenesis
of subduction-related lavas from Martinique, Lesser Antilles. Journal of
Geophysical Research 91, 5943-5962.
DePAOLO D.J. and WASSERBURG G.J. 1976. Nd isotopes variations and
petrogenetic models. Geophysical Research Letters 3, 249-252.
DICKINSON W.R. 1968. Circum-Pacific andesite types. Journal of Geophysical
Research 73, 2261-2269. 132
DICKINSON W.R. 1970. Relations of andesites, granites, and derivative
sandstones to arc-trench tectonics. Reviews of Geophysics and Space Physics
8, 813-860.
DOSTAL J., ZENTILLI M., CAELLES J.C. and CLARK A.H. 1977.
Geochemistry and origin of volcanic rocks of the Andes (26° - 28° S).
Contributions to Mineralogy and Petrology 63, 113-128.
DUPRE B. and ALLEGRE CJ. 1983. Pb-Sr isotope variation in Indian Ocean
basalts and mixing phenomena. Nature 303, 142-146.
EFFENDI A.C. 1974. Geologic map of the Bogor Quadrangle, Java. Geological
Survey of Indonesia, Scale 1:250,000.
EGGLER D.H. 1972. Water saturated and undersaturated melting relations in a
Paricutin andesite and estimate of water content in the natural magma.
Contributions to Mineralogy and Petrology 34, 261-271.
EGGLER D.M. and BURNHAM C.W. 1973. Crystallization and fractionation
trends in the system andesite - H2O - CO2 - O2 at pressures to 10 kb.
Geological Society of America Bulletin 84, 2517-2532.
ELEFTHERIADIS G., CHRISTOFIDES G. and KASSOLI-FOURNARAKI A.
1984. Geochemistry of the high-K calcalkaline basaltic sills and dykes in the
south Rhodope Massif (N. Greece). Bulletin Volcanologique 47, 569-579.
EWART A. 1976. Mineralogy and chemistry of modern orogenic lavas: some
statistics and implications. Earth and Planetary Science Letters 31,417-432.
EWART A. 1982. The mineralogy and petrology of Tertiary-Recent orogenic
volcanic rocks: with special reference to andesite - basaltic compositional
range. In: R.S. Thorpe., ed., Andesites: orogenic andesites and related rocks,
pp. 25-95. John Wiley and Sons.
EWART A. and BRYAN W.B. 1973. The petrology and geochemistry of the
igneous rocks from Eua, Tonga Islands. Geological Society of America
Bulletin 83, 3281-3298. 133
EWART A. and LE MAITRE R.W. 1985. Some regional compositional differences
within Tertiary-Recent orogenic magmas. Chemical Geology 30,257-283.
FAURE G. 1986. Principles of isotope geology. John Wiley and Sons.
FISHER R.V. anD SCHMINKE H.-U. 1984. Pyroclastic Rocks. Springer-Verlag.
Berlin.
FITCH TJ. 1970. Earthquake mechanism and island arc tectonics in the
Indonesian-Philippine region. Seismological Society of America Bulletin 60,
565-991.
FITCH TJ. and MOLNAR P. 1970. Focal mechanisms along inclined earthquake
zones in the Indonesian-Philippine region. Journal of Geophysical Research
75, 1431-1440.
FODEN J.D. 1983. The petrology of the calcalkaline lavas of Rinjani Volcano, East
Sunda Arc: a model for island arc petrogenesis. Journal of Petrology 24,
98-130.
FREY F.A. 1984. Rare earth element abundances in upper mantle rocks. In:
Henderson P. ed., Rare earth element geochemistry, pp. 153-203. Elsevier.
FREY F.A., BRYAN W.B. and THOMPSON G. 1974. Adantic ocean floor:
geochemistry and petrology of basalts from Legs 2 and 3 of the Deep Sea
Drilling Project. Journal of Geophysical Research 79, 5507-5527.
FREY F.A., GERLACH D.C., ESCOBAR L.L. and VILLAVICENCIO F.M.
1984. Petrogenesis of the Laguna del Maule volcanic complex. Contributions
to Mineralogy and Petrology 88, 133-149.
FREY F.A and GREEN D.H. 1974. The mineralogy, geochemistry and origin of
lherzolite inclusions in Victorian basanites. Geochimica et Cosmochimica Acta
38, 1023-1059.
FREY F.A., GREEN D.H. and ROY S. 1978. Integrated models of basalt
petrogenesis: a study of quartz tholeiites to olivine melilitites from
southeastern Australia utilizing geochemical and experimental petrologic data.
Journal of Petrology 19,463-513. 134
GARCIA M.O. and JACOBSON S.S. 1979. Crystal clots, amphibole fractionation
and the evolution of calc-alkaline magmas. Contributions to Mineralogy and
Petrology 69, 319-332.
GAST P.W. 1968. Trace element fractionation and the origin of tholeiitic and
alkaline magma types. Geochimica et Cosmochimica Acta 32, 1057-1086.
GEST D.E. and McBIRNEY A.R. 1979. Genetic relations of shoshonitic and
absarokitic magmas, Absaroka Mountains, Wyoming. Journal of Volcanology
and Geothermal Research 6, 85-104.
GILL J.B. 1970. Geochemistry of Viti Levu, Fiji, and its evolution as an island
arc. Contributions to Mineralogy and Petrology 27, 179-203.
GILL J.B. 1972. The geochemical evolution of Fiji. Unpublished PhD thesis,
Australian National University.
GILL J.B. 1978. Role of trace element partition coefficients in models of andesite
genesis. Geochimica et Cosmochimica Acta 42, 709-724.
GILL J.B. 1981. Orogenic andesites and plate tectonics. Springer-Verlag, Berlin.
GORTON M.P. 1974. The geochemistry and geochronology of the New Hebrides.
Unpublished PhD thesis, Australian National University.
GREEN D.H. 1973. Conditions of melting of basanite magma from garnet
peridotite. Earth and Planetary Science Letters 17,456-465.
GREEN D.H. and RINGWOOD A.E. 1967. The genesis of basaltic magmas.
Contributions to Mineralogy and Petrology 15, 103-190.
GREEN T.H. 1980. Island arc and continent - building magmatism - A review of
petrogenetic models based on experimental petrology and geochemistry.
Tectonophysics 63, 367-385.
GREEN T.H. and RINGWOOD A.E. 1968. Genesis of the calc-alkaline igneous
rock suite. Contributions to Mineralogy and Petrology 18, 105-162.
GREEN T.H. and WATSON E.B. 1982. Crystallization of apatite in natural
magmas under high pressure hydrous conditions, with particular reference to
orogenic rock series. Contributions to Mineralogy and Petrology 79, 96-105. 135
GRIFFIN W.L. and O'REILLY S.Y. 1987. Is the continental Moho the crust-
mantle boundary? Geology 15, 241-244.
GROVE T.L., GERLACH D.C. and S ANDO T.W. 1982. Origin of calc-alkaline
series lavas at Medicine Lake volcano by fractionation, assimilation and
mixing. Contributions to Mineralogy and Petrology 80, 160-182.
HALL A. 1986. Igneous Petrology. Longman Scientific and Technical. John Wiley
and Sons.
HAMELIN B. and ALLEGRE CJ. 1985. Large-scale regional units in the depleted
upper mantle revealed by an isotopic study of the South-West Indian Ridge.
Nature 315, 196-199.
HAMILTON W. 1979. Tectonics of the Indonesian region. US Geological Survey,
Professional Paper 1078, 345p.
HARRIS P.G. 1957. Zone refining and the origin of potassic basalts. Geochimica
et Cosmochimica Acta 12, 195-208.
HART S.R. 1964. The petrology and isotopic mineral age relations of a contact
zone, Front Range, Colorado. Journal of Geology 72, 493-525.
HART S.R. 1984. A large-scale isotope anomaly in the southern hemisphere
mande. Nature 309, 753-757.
HART. S.R., BROOKS C, KROGH T.E., DAVIS G.L. and NAVA D. 1970.
Ancient and modern volcanic rocks: a trace element model. Earth and
Planetary Science Letters 10,17-28.
HASKIN L.A., HASKIN M.A., FREY F.A. and WILDEMAN T.R. 1968.
Relative and absolute terrestrial abundances of the rare earths. In: Ahrens
L.H. ed., Origin and distribution of the elements, pp. 889-912. Pergamon
Press.
HATHERTON T. and DICKINSON W.R. 1969. The relationship between
andesite volcanism and seismicity in Indonesia, the Lesser Antilles, and other
island arcs. Journal of Geophysical Research 74, 5301-5310. 136
HAWKESWORTH CJ. and VOLLMER R. 1979. Crustal contamination versus
enriched mantle: 143Nd/144Nd and 87Sr/86Sr evidence from the Italian
volcanics. Contributions to Mineralogy and Petrology 69,151-165.
HEIRTZLER J.R., CAMERON P.J., COOK PJ. and VEEVERS JJ. 1978. The
Argo Abyssal Plain. Earth and Planetary Science Letters 48, 21-31.
HELLMAN P.L.and GREEN T.H. 1979. The role of sphene as an accessory
phase in the high-pressure partial melting of hydrous mafic compositions.
Earth and Planetary Science Letters 42, 191-201.
HELZ R.T. 1979. Alkali exchange between hornblende and melt: a temperature-
sensitive reaction. American Mineralogist 64, 953-965.
HILDRETH W. 1979. The Bishop tuff: evidence for the origin of compositional
zonation in silicic magma chamber. Geological Society of America, Special
Paper 180, 43-75.
HOFFMAN A.W. and HART S.R. 1978. An assessment of local and regional
isotopic equilibrium in the mande. Earth and Planetary Science Letters 38,
44-62.
HOSHINO K and SUNOTO W. 1978. Geologic Structure. Geological Survey of
Indonesia, Special Publication 6, 136-144.
HUGHES CJ. and HUSSEY E.M. 1976. M and Mg values in igneous rocks:
proposed usage and a comment on currently employed Fe203 corrections.
Geochimica et Cosmocliimica Acta 40,485-486.
HUTCHISON C.S. 1973. Tectonic evolution of Sundaland; a Phanerozoic
Synthesis. Geological Society of Malaysia Bulletin 6, 61-86.
HUTCHISON C.S. 1976. Indonesian active volcanic arc: K, Sr and Rb variation
with depth to the Benioff Zone. Geology 4,407-408.
HUTCHISON C.S. 1982. Regional distribution and character of active andesite
volcanism, Indonesia. In: R.S. Thorpe., ed., Andesites: orogenic andesites
and related rocks, pp. 207-224. John Wiley and Sons. 137
IRVING A J. 1978. A review of experimental studies of crystal/liquid trace element
partitioning. Geochimica et Cosmochimica Acta 42,743-770.
IRVING A J. and FREY F.A. 1984. Trace element abundances in megacrysts and
their host basalts; constraints on partition coefficients and megacrysts genesis.
Geochimica et Cosmochimica Acta 48,1201-1221.
JACOB T. 1972. The absolute age of the Djetis beds at Modjokerto. Antiquity 46,
148-148.
JAHN B., SHIH C. and MURTY V.R. 1974. Trace element geochemistry of
Archean volcanic rocks. Geochimica et Cosmochimica Acta 38,611-627.
JAKES P. and GILL J.B. 1970. Rare earth elements and the island arc tholeiitic
series. Earth and Planetary Science Letters 9,17-28.
JAKES P. and SMITH I.E. 1970. High potassium calc-alkaline rocks from Cape
Nelson, Eastern Papua. Contribution to Mineralogy and Petrology 28,
259-271.
JAKES P. and WHITE A.J.R. 1969. Structure of the Melanesia arcs and
correlation with distribution of magma types. Tectonophysics 8, 223-236.
JAKES P. and WHITE A.J.R. 1970. K/Rb ratios of rocks from island arcs.
Geochimica et Cosmochimica Acta 34, 849-856.
JAKES P. and WHITE A.J.R. 1972. Major and trace element abundances in
volcanic rocks of orogenic areas. Geological Society of America Bulletin 83,
29-40.
JOHNSON R.W., MACKENZIE D.E. and SMITH I.E.M. 1978. Delayed partial
melting of subduction modified mantle in Papua New Guinea. Tectonophysics
46, 197-216.
JOLLY P.T. 1971. Potassium-rich igneous rocks from Puerto Rico. Geological
Society of America Bulletin 82, 399-408.
JOPLIN G.A. 1968. The shoshonite association: a review. Geological Society of
Australia, Journal 15,275-294. 138
JOPLIN G.A., KISS E., WARE N.G. and WIDDOWSON J.R. 1972. Some chemical data on members of the shoshonite association. Mineralogical
Magazine 38, 936-945.
KATILI J.A. 1973a. On fitting certain geological and geophysical features of the
Indonesia island arc to the new global tectonics. In: Coleman P.J., ed. The
Western Pacific: Island Arcs, Marginal Seas, Geochemistry, pp. 287-305.
University of Western Australia Press.
KATILI J.A. 1973b. Geochronology of West Indonesia and its implications on
plate tectonics. Tectonophysics 19, 195-212.
KELLEHER J. and McCANN WJ. 1976. Buoyant zones, great earthquakes, and
unstable boundaries of subduction. Journal of Geophysical Research 81,
4885-4896.
KELLER J. 1974. Petrology of some volcanic rock series of Aeolian Arc, southern
Tyrrhenian Sea: calc-alkaline and shoshonitic associations. Contributions to
Mineralogy and Petrology 46, 29-47.
KENNETT J.P. and THUNELL R.C. 1975. Global increase Quaternary explosive
volcanism. Science 187, 497-503.
KENYON C.S. and BEDDOES JR. L.R. 1977. Geothermal gradient map of
Southeast Asia: South East Asia Petroleum Exploration Society and
Indonesian Petroleum Association, pp. 50.
KESSON S.E. and SMITH I.E. 1972. Ti©2 content and the shoshonite and
alkaline associations. Nature: Physical Science 236, 110-111.
KETNER K.B., KASTOWO, MODJO S., NAESER C.W., OBRADOVICH J.D.,
ROBINSON K.,SUPTANDAR T and WIKARNO. 1976. Pre-Eocene rocks
of Java, Indonesia. US Geological Survey, Journal of Research 4, 605-614.
KIECKHEFER R.M., SHOR G.G. and CURRAY J.R. 1980. Seismic refraction
studies of the Sunda trench and fore arc basin. Journal of Geophysical
Research 85, 863-869. 139
KOKELAAR P. 1985. Petrology and geochemistry of Rhoball volcanic complex:
amphibole-dominated fractionation at an Early Ordovocian arc volcano in
North Wales. Journal of Petrology 27, 887-914.
KUNO H. 1950. Petrology of the Hakone Volcano and adjacent areas, Japan.
Geological Society of America Bulletin 61, 957-1015.
KUNO H. 1966. Lateral variation of basalt magma type across continental margins
and island arcs. Bulletin volcanologique 29, 195-222.
KUSHIRO I 1972. Effect of water on the composition of magma formed at high
pressures. Journal of Petrology 13, 311 -334.
KUSUMADINATA R.P. 1978. Geologi minyak dan gasbumi. Penerbit ITB.
Bandung.
LAMBERT RSt. J., HOLLAND J.G. and OWEN P.F. 1974. Chemical petrology
of a suite of calc-alkaline lavas from Mount Arafat, Turkey. Journal of
Geology 82, 419-438.
LANGMUIR CM., BENDER J.F., BENCE A.E. and HANSON G.N. 1977.
Petrogenesis of basaltsfrom the FAMOUS area: Mid-Adantic Ridge. Earth
and Planetary Science Letters 36,133-156.
LANGMUIR C.H., VOCKE JR. R.D., HANSON G.N. and HART S.R. 1978. A
general mixing equation with applications to icelandic basalts. Earth and
Planetary Science Letters 37, 380-392.
LE B AS M J. 1962. The role of aluminium in igneous clinopyroxenes with relation
to their parentage. American Journal of Science 260,267-288.
LE PICHON X. 1968. Sea-floor spreading and continental drift. Journal of
Geophysical Research 73, 3661-2705.
LEAKE B.E. 1978. Nomenclature of amphiboles. American Mineralogist 63,
1023-1052.
LEEMAN W.P. 1974. Comparison of Rb/Sr, U/Pb, and rare earth characteristics
of sub-continental and sub-oceanic mande regions. Oregon Department of
Geology and Mineral Industries Bulletin 96,149-167. 140
LINDSLEY D.H. and ANDERSEN DJ. 1983. A two-pyroxene thermometer.
Journal of Geophysical Research 88, 887-906.
LINDLSEY D.H. 1983. Pyroxene thermometry. American Mineralogist 68,
477- 493.
LOWDER G.G. and CARMICHAEL I.S.E. 1970. The volcanoes and caldera of
Talasea, New Britain. Geological Society of America Bulletin 81, 17-38.
LUHR J.F. and CARMICHAEL I.S.E. 1980. The Colima Volcanic Complex,
Mexico. Contributions to Mineralogy and Petrology 70, 343-372.
LUNG C.K. and KIRCKPATRICK RJ. 1982. Pre eruption history of phyric
basalts from DSDP Legs 45 and 46: evidence from morphology and zoning
pattern in plagioclase. Contributions to Mineralogy and Petrology 79, 13-27.
LUYENDYK B.P. 1970. Dips of downgoing lithospheric plates beneath island
arcs. Geological Society of America Bulletin 81, 3411-3416.
MACKENZIE D.E. and CHAPPELL B.W. 1972. Shoshonitic and calc-alkaline
lavas from the Highlands of Papua New Guinea. Contributions to Mineralogy
and Petrology 35, 50-62.
MANETTI P. PECCERILLO A and POLI G. 1979. REE distribution in Upper
Cretaceous calcalkaline and shoshonitic volcanic rocks from Eastern
Srednorgie (Bulgaria) Chemical Geology 26, 51-63.
MANKINNEN E.A. and DALRYMPLE G.B. 1979. Revised geomagnetic polarity
time scale for the interval 0-5 m.y. B.P. Journal of Geophysical Research 84,
615-626.
MARCELOT G., MAURY R.C. and LEFEVRE CH. 1983. Mineralogy of
Erromango Lavas (New Hebrides): evidence of an early stage fractionation in
island arc basalts. Lithos 16, 135-151.
MARSH B.D. 1981. On the crystallinity, probability of occurence, and rheology of
lava and magma. Contributions to Mineralogy and Petrology 78, 85-98. 141
McBIRNEY A.R. 1979. Effects of assimilation. In: Yoder H.S. ed. The evolution
of the igneous rocks, pp. 307-338. Princeton University Press, Princeton,
New Jersey.
McBIRNEY A.R. 1984. Igneous Petrology. Freeman, Cooper and Company.
MCCARTHY M.J. and CAWTHORN R.G. 1980. Changes in initial 87Sr/8(5Sr
ratio during protracted fractionation in igneous complexes. Journal of
Petrology 21, 245-264.
MCDOUGALL I. 1978. Revision of the geomagnetic polarity time scale for the last
5 m.y B.P. In: Zartman R.E. ed, Geochronology, cosmochronology, isotope
geology, pp. 287-289.
MEIJER A. 1976. Pb and Sr isotopic data bearing as the origin of volcanic rocks
from the Mariana island arc system. Geological Society of America Bulletin
87, 1358-1369.
MENZIES J. and MURTHY V.R. 1980. Nd and Sr isotope geochemistry of
hydrous mantle nodules and their host alkali basalts: implications for local
heterogeneities in metasomatically veined mande. Earth and Planetary Science
Letters 46, 323-334.
MIDDLEMOST E.A.K. 1985. Magmas and magmatic rocks. An introduction to
igneous petrology. Longman In., New York.
MONTFRANS H.M. van. 1971. Paleomagnetic dating in the North Sea Basin.
Diss. Amsterdam.
MOORE G.F., CURRAY J.R., MOORE D.G. and KARIG D.E. 1978. Variations
in geologic structure along the Sunda forearc, northeastern Indian Ocean.
Department of Geological Sciences, Cornell University, Ithaca, NY 14853.
MORRIS J.D. and HART S.R. 1983. Isotopic and incompatible element
constraints on the genesis of island arc volcanics from Cold Bay and Amak
Island, Aleutians, and implications for mantle structure. Geochimica et
Cosmochimica Acta 47,2015-2033. 142
MORRISON W. 1980. Characteristic and tectonic setting of the shoshonite rock
association. Lithos 13, 97-108.
MUHARDJO, RAB E.S., YUSUP R., YUHAN and SUNDORO H. 1984.
Laporan penyelidikan geologi daerah panasbumi G.Ungaran Jawa Tengah.
Proyek Survai dan Pengujian Potensi Sumber Panasbumi, Direktorat
Vulkanologi, Indonesia. Unpublished report.
NICHOLLS I.A. 1974. Liquids in equilibrium with peridotitic mineral assemblages
at high water pressures. Contributions to Mineralogy and Petrology 45,
289-316.
NICHOLLS LA. and HARRIS K.L. 1980. Experimental rare earth element
partition coefficients for garnet, clinopyroxene and amphibole coexisting with
andesitic and basaltic liquids. Geochimica et Cosmochimica Acta 44,
287-308.
NICHOLLS LA. and RINGWOOD A.E. 1972. Production of silica-saturated
tholeiitic magmas in island arcs. Earth and Planetary Science Letters 17,
243-246.
NICHOLLS LA. and RINGWOOD A.E. 1973. Effect of water on olivine stability
in tholeiitic and the production of silica-saturated magmas in the island arc
environments. Journal of Geology 81, 285-300.
NICHOLLS LA. and WHITFORD DJ. 1976. Primary magma associated with
Quaternary volcanism in the western Sunda Arc, Indonesia. In: Johnson
R.W. ed., Volcanism in Australasia, pp. 77-90. Amsterdam, Elsevier.
NICHOLLS LA. and WHITFORD D J. 1978. Geochemical zonation in the Sunda
volcanic arc, and the origin of K-rich lavas. Bulletin of the Australian Society
of Exploration Geophysicists 9, 93-98.
NICHOLLS LA., WHITFORD DJ., HARRIS K.L. and TAYLOR S.R. 1980.
Variation in the geochemistry of mande sources for tholeiitic and calc-alkaline
mafic magmas, western Sunda volcanic arc, Indonesia. Chemical Geology
30, 177-199. 143
NICHOLLS J. and CARMICHAEL I.S.E. 1969. A commentry on the absarokite-
shoshonite-banakite series of Wyoming, U.S.A. Schweizerische
Mineralogische und Petrograpische Mitteilungen 49,47-64.
NILLSON T. 1983. The Pleistocene: Geology and life in the Quaternary Ice Age.
Berlings Arlov.
NTNKOVICH D. and BURCKLE L.H. 1978. Absolute age of the base of the
Hominid-bearing beds in eastern Java. Nature 275, 306-308.
NISfflMURA S., THJO K.H. and HEHUWAT F. 1980. Fission-track ages of the
tuffs of the Pucangan and Kabuh formations, and the tektite at Sangiran,
Central Java. Physics Geology of Indonesian Island Arcs, pp. 72-80.
NOBLE D.C. and KORRINGA M.K. 1974. Strontium, rubidium, potassium, and
calcium variations in Quaternary lavas, Crater Lake, Oregon, and their
residual glasses. Geology 7, 187-190.
O'HARA M.J. 1973. Non-primary magmas and dubious mande plume beneath
Iceland. Nature 243, 507-508.
O'NIONS R.K. and PANKHURST RJ. 1974. Rare earth element distribution in
Archaean gneisses and anorthosites, Godthab area, West Greenland. Earth
and Planetary Science Letters 22, 328-338.
OLIVER J., COOK F. and BROWN L. 1983. COCORP and the continental crust.
Journal of Geophysical Research 88, 3329-3347.
ORCHISTON D.W. and SIESSER W.G. 1982. Chronostratigraphy of the Plio-
Pleistocene fossil Hominid of Java. 7n:BarstraG J. and Casparie W.A. eds.
Modern Quaternary Research in Southeast Asia 7,131-149.
OTTEN M.T. 1984. The origin of brown hornblende in the Artfjallet gabbro and
dolerites. Contributions to Mineralogy and Petrology 86,189-199.
OVERSBY V.M. and EWART A. 1972. Lead isotopic compositions of Tonga -
Kermadec volcanic and their petrogenetic significance. Contributions to
Mineralogy and Petrology 37,181-210. 144
OXBURGH E.R. and TURCOTTE D.L. 1971. Origin of paired metamorphic
belts and crustal dilation in island arc regions. Journal of Geophysical
Research 16, 1315-1327. PAPIKE J.J., CAMERON K.L. and BALDWIN K. 1974. Amphiboles and
pyroxenes: characteristization of other than quadrilateral components and
estimates of ferric ironfrom microprobe data. Geological Society of America,
Abstracts with Programs 6,1053-1054.
PE-PIPER G. 1983. Triassic shoshonites and andesites, Lakmon Mountains, Western Continental Greece : differences in primary geochemistry and sheet
silicate alteration products. Lithos 16, 23-33.
PECCERILLO A. 1985. Roman Comagmatic Province (Central Italy): Evidence
for subduction - related magma genesis. Geology 13, 102-106.
PECCERILLO A. and TAYLOR S.R. 1976a. Geochemistry of Eocene calc-
Ik alkaline volcanic rocks from the Kastamanu area, "Northern Turkey. Contributions to Mineralogy and Petrology 58, 63-81.
PECCERILLO A. and TAYLOR S.R. 1976b. Rare earth elements in East Carpathian volcanic rocks. Earth and Planetary Science Letters 32, 121-126.
PERFIT M.R., GUST D.A., BENCE A.E., ARCULUS RJ. and TAYLOR S.R.
1980. Chemical characteristics of island arc basalts: implications for mantle sources. Chemical geology 30, 227-258.
POSAVEC M., TAYLOR D., van LEEUWEN Th. and SPECTOR A. 1973.
Tectonic controls of volcanism and complex movements along the Sumatra fault system. Geological Society of Malaysia Bulletin 6,43-60.
POWELL R. and POWELL M. 1977. Geothermometry and oxygen barometry using coexisting iron titanium oxides: a reappraisal. Mineralogical Magazine 41, 257-263.
PREVOT V.K. 1976. Chronologie des inversions du champ magnetique terrestre
du Quatemaire. Bulletin de la Societe geologique de France 18,951-958. 145
REED S.J.B. and WARE N.G. 1975. Quantitative electron microprobe analysis of
silicates using energy-dispersive X-ray spectrometry. Journal of Petrology
16, 499-519.
RICHARD P., SCHIMIZU N. and ALLEGRE CJ. 1976. 143Nd/146Nd, a
natural tracer: an application to oceanic basalts. Earth and Planetary Science
Letters 31, 269-278.
RINGWOOD A.E. 1974. Petrological evolution of island arc systems. Journal of
the Geological Society of London 130, 183-204.
RINGWOOD A.E. 1975. Composition and petrology of the Earth's mantle.
McGraw Hill, New York.
RINGWOOD A.E. 1982. Phase transformations and differentiation in subducted
lithosphere: implications for mantle dynamics, basalt petrogenesis, and crustal
evolution. Journal of Geology 90, 611-643.
RINGWOOD A.E. 1966. The chemical composition and origin of the earth. In:
HurleyP.M. ed., Advances in earth sciences. MIT Press, Cambridge, Mass.
RITTMANN A. 1953. Magmatic character and tectonic position of the Indonesian
volcanoes. Bulletin Volcanologique 14, 45-58.
RITTMANN A. 1973. Stable mineral assemblages of igneous rocks. Springer-
Verlag.
ROBINSON P., SPEAR F.S., SCHUMACHER J.C., LAIRD J., KLEIN C,
EVANS B.W. and DOOLAN B.L. 1982. Phase relations of metamorphic
amphiboles: natural occurence and theory. In: Mineralogical Society of
America, pp 1-227. Reviews in mineralogy 9b, Amphiboles: petrology and
experimental phase relations.
ROBINSON P.T. and WHITFORD DJ. 1974. Basalts from the Eastern Indian
Ocean, DSDP Leg 27. In: Veevers JJ. and J.R. Heirtzler LR. eds. Initial
Report Deep Sea Drilling Project 27, pp. 551-559. U.S. Government
Printing Office. 146
ROEDER P.L. and EMSLIE R.F. 1970. Olivine-liquid equilibrium. Contributions
to Mineralogy and Petrology 29, 275-289.
RYERSON F.J. and WATSON E.B. 1987. Rutile saturation in magmas:
implications for Ti-Nb-Ta depletion in island arc basalts. Earth and Planetary
Science Letters 86, 225-239.
SANNY T. 1985. Geology dan geofisika daerah sebelah Utara G. Ungaran.
Unpublished Ir. thesis, Institute Teknologi Bandung, Indonesia.
SATO H. 1977. Nickel content of basaltic magmas: identification of primary
magmas and a measure of the degree of olivine fractionation. Li thos 10,
113-120.
SAUNDERS A.D., TARNEY J. and WEAVER S.D. 1980. Transverse
geochemical variations across the Antarctic Peninsula: implications for the
genesis of calc-alkaline magmas. Earth and Planetary Science Letters 46,
344-360.
SCHILLING J.G. 1973. Iceland mantle plume. Nature 246, 141-143.
SEMAH F. 1982. Pliocene and Pleistocene geomagnetic reversals recorded in the
Gemolong and Sangiran Domes (Central Java). In: Barstra G J. and Casparie
W. A. eds. Modern Quaternary Research in Southeast Asia 7, pp. 151 -164.
SHAPERO L. and BRANNOCK W.W. 1956. Rapid analysis of silicate rocks. US
Geological Survey, Bulletin 1036-C.
SHAW D.M. 1968. A review of K-Rb fractionation trends by covariance analysis.
Geochimica et Cosmochimica Acta 32, 573-601.
SHAW D.M. 1970. Trace element fractionation during anatexis. Geochimica et
Cosmochimica Acta 34, 237-243.
SILVER E.A., GILL LB., SCHWARTZ D., PRASETYO H. and DUNCAN R.A.
1985. Evidence for a submerged and displaced continental borderland, north
Banda Sea, Indonesia Geology 13, 687-691.
SMITH LD. and FORSTER LH. 1969. Geomagnetic reversal in Brunhes normal
polarity epoch. Science 163, 565-567. 147
SMITH R.L. 1979. Ash flow magmatism. Geological Society of America Bulletin,
Special Paper 180, 5-27.
STERN CR. and WYLLIE P.J. 1978. Phase compositions through crystallization
intervals in basalt-andesite-H20 at 30 Kb with implications for subduction
zone magmas. American Mineralogist 63, 641-663.
STEWART D.C. 1975. Crystal clots in calc-alkaline andesites as breakdown
products of high-Al amphiboles. Contributions to Mineralogy and Petrology
53, 195-204.
STOUT J.H. 1972. Phase petrology and mineral chemistry of coexisting
amphiboles from Telemark, Norway. Journal of Petrology 13,99-145.
SUGEVIURA A. 1968. Spatial relations of basaltic magmas in island arcs. In: Hess
H.H. and Poldervaat A. eds. Basalts, pp. 537-571. Interscience.
SUGIMURA and UYEDA. 1973. Island arcs: Japan and its environments.
Amsterdam, Elsevier.
SUN S.S. 1980. Lead isotopic study of young volcanic rocks from Mid-Ocean
Ridges, ocean islands and island arc. Philosophical Transactions of the Royal
Society, London 297, 409-445.
SUN S.S. and NESBITT R.W. 1978. Geochemical regularities and genetic
significance of ophiolitic basalts. Geology 6, 689-693.
TAKAHASHI E and KUSHIRO I. 1983. Melting of dry peridotite at high
pressures and basalt magma genesis. American Mineralogist 68, 859-879.
TATSUMI Y., HAMILTON D.L. and NESBITT R.W. 1986. Chemical
characteristics of fluid phase released from a subducted lithosphere and the
origin of arc magmas: evidence from high pressure experiments and natural
rocks. Journal ofVolcanolgy and Geothermal Research 29,293-309.
TAYLOR S.R. and MCLENNAN S.M. 1985. The continental crust, its
composition and evolution. Blackwell, Oxford. 148
TERA F., BROWN L„ MORRIS J., SACKS I.S., KLEIN J. and MIDDLETON
R. 1986. Sediment incorporation in island-arc magmas: inferences from
lOBe. Geochimica et Cosmochimica Acta 50, 535-550.
THADEN E.R., SUMADIMARDJA H, RICHARDS W.P. 1975. Geologic map
of the Magelang and Semarang Quadrangles, Java. Geological Survey of
Indonesia, Scale 1:100,000. THIRWALL M.R. and GRAHAM A.M. 1984. Evolution of high-Ca, High-Sr C - series basalts from Grenada, Leser Antilles: the effects of intra-crustal contamination. Journal of the Geological Society of London 141,427-445.
THOMPSON R.N. 1982. Magmatism of the British Tertiary volcanic province.
Scottish Journal of Geology 18, 49-107.
TJIA H.D. 1966. Volcanic lineaments in the Indonesian island arcs. Bulletin
Volcanologique 31, 85-96.
UNTUNG M. and SUDARMO W.G. 1975. Structural pattern of Java and Madura
V as result of preliminary interpretation of gravity data. Geology of Indonesia 2, 15-24.
VELDE B. and KUSHIRO I. 1978. Structure of sodium alumino-silicate melts
quenched at high pressure; infra red and aluminium K-radiation data. Earth
and Planetary Science Letters 4,137-140.
VENTURELLI G., THORPE R.S., DAL PIAZ G.T., DEL MORE A. and PETTS
PJ. 1984. Petrogenesis of calc-alkaline, shoshonitic and associated
ultrapotassic oligocene volcanic rocks from the Northwestern Alps, Italy.
Contributions to Mineralogy and Petrology 86, 209-220.
VERBEEK R.D. and FENNEMA R. 1896. Geologische beschrijving van Java en Madoera. Amsterdam, 276-277.
VERHOOGEN J. 1962. Distribution oftitanium between silicates and oxides in
igneous rocks. American Journal of Science 260, 211-220. 149
WARTONO R., RUMIDI S., ROSIDI H.M.D. 1977. Geological map of the
Yogyakarta Quadrangle, Java. Geological Survey of Indonesia. Scale
1:100,000.
WASS S.Y. 1979. Multiple origins of clinopyroxenes in alkali basaltic rocks.
Lithos 12, 115-132.
WASS S.Y. 1980. Geochemistry and origin xenolith.- bearing and related alkali
basaltic rocks from the Southern Highland, New South Wales, Australia.
American Journal of Science 280A, 639-666.
WASS S.Y. and ROGERS N.W. 1980. Mantle metasomatism - precursor to
continental alkaline volcanism. Geochimica et Cosmochimica Acta 44,
1811-1823.
WATKINS N.D. 1972. Review of the development of the geomagnetic polarity
time scale and discussions of prospects for its finer definition. Geological
Society of America Bulletin 83, 551-574.
WESTERCAMP D. and MERVOYER B. 1976. Les series volcaniques de la
Martinique et de la Guadeloupe (F.W.L.). France Bureau de Recherches
Geologiques et Minieres Bulletin 4,229-242.
WHELLER G.E., VARNE R., FODEN J.D. and ABBOTT M.J. 1987.
Geochemistry of Quaternary volcanism in the Sunda-Banda Arc, Indonesia,
and three-component genesis of island arc basaltic magmas. Journal of
Volcanology and Geothermal Research 32,137-159.
WHITE W.M. 1985. Sources of oceanic basalts: radiogenic isotopic evidence.
Geology 13, 115-118.
WHITE W.M., SCHILLING J.G. and HART S.R. 1976. Evidence for the Azores
mantle plume from the strontium isotope geochemistry of the central North
Atlantic. Nature 263, 659-663.
WHITFORD DJ. 1975a. Geochemistry and Petrology of volcanic rocksfrom the
Sunda Arc, Indonesia. Unpublished PhD thesis, Australian National
University. 150
WHITFORD DJ. 1975b. Strontium isotopic studies of the volcanic rocks of the
Sunda Arc, Indonesia, and their petrogenetic implications. Geochimica et
Cosmochimica Acta 39, 1287-1302.
WHITFORD DJ. and JEZEK P. 1982. Isotopic constraints on the role of
subducted sialic material in Indonesian island arc magmatism. Geological
Society of America Bulletin 93, 504-513.
WHITFORD D J. and NICHOLLS LA. 1976. Potassium variation in lavas across
the Sunda Arc in Java and Bali. In: Johnson R.W. ed. Volcanism in
Australasia, pp. 63-75. Elsevier.
WHITFORD DJ., NICHOLLS LA. and TAYLOR S.R. 1979a. Spatial variations
in the geochemistry of Quaternary lavas across the Sunda Arc in Java and
Bali. Contributions to Mineralogy and Petrology 70, 341-356.
WHITFORD D.J., WHITE W.M. and JEZEK P.A. 1979b. Nd isotopic
composition of Recent andesites from Indonesia. Carnegie Institution of
Washington Year Book 78, 304-308.
"a WHITFORD DJ., WHITE W."M. and JEZEK P.A. 1981. Neodymium isotopic
composition of Quaternary island arc lavas from Indonesia. Geochimica et
Cosmochimica Acta 45, 989-995.
WOOD D.A. 1979. A variably veined sub oceanic upper mantle: genetic
significance for mid-ocean ridge basalts from geochemical evidence. Geology 7, 499-503.
WRIGHT T.L. and FISKE R.S. 1971. Origin of the differentiated and hybrid lavas
of Kilauea volcano, Hawaii. Journal of Petrology 12, 1-65.
WRIGHT T.L. and OKAMURA R.T. 1977. Cooling and crystallization of
tholeiitic. US Geological Survey, Professional Paper 1004, 48p.
WYERS G.P. and BARTON M. 1986. Petrology and evolution of transitional
alkaline-subalkaline lavas from Patmos, Dodecanesos, Greece: evidence for
fractional crystallisation, magma mixing and assimilation. Contributions to Mineralogy and Petrology 93,297-311. 151
WYERS P. and BARTON M. 1987. Geochemistry of a transitional ne-trachybasalt
- Q-trachyte lava series from Patmos (Dodecanesos), Greece: further evidence
for fractionation, mixing and assimilation. Contributions to Mineralogy and
Petrology 97, 279-291.
YOKOYAMA I., SURYO I. and NAZHAR B. 1970. Volcanological survey of
Indonesian volcanoes. A gravity survey in Central Java. Bulletin of the
Earthquake Research Institute 48, 303-315. 152 153
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LEGEND:
Active subduction zone V Cretaceous subduction zone • • Active volcanoes Cretaceous magmatic arc
C Border foreland basin Trlasslc-Jurassic magmatic arc
Tertiary subduction zone ^VVV^ Permian subduction zone
BH Tertiary magmatic arc Permianr I T magmatic arc
Fig. 2-3. The distribution of Permian to Recent subduction zones, magmatic arcs and active volcanoes on the western side of the Indonesian Archipelago (after Katili, 1973b). 158
106' 108' 110' 112' "4'. __! "Vzii r^-_ ' JMA T~"~' \- 26- •25 ^"~~^ \^ 24. [__1NCH - A Subducting ocoant llthoiphco plelo '23 ~^<~__4__ 8 Molanoo, Imbttcatod jodlmonta/y rocki, 12 - "VDlAN 22 and loctonlcally Intwcalatod illca* trom OCEAN ocaanlc plolo
1 1 1 1 1 LOCALITY MAP
0-1 10- > ISnallo- layt'l
20- "" llnt,fmtolala lajra'l 30 3 OCEANIC UlTRAMAFIC MANTLE '•' lo..p Ur»'i 40 A 50- km
Expanded scale
-5000
•6000 5
I I . J I 1 l l ! I . I • t , | | | . | , I |.| ,| wedoe ol i-ttvtc-Ud sediments 7000 snd —telsnQe
JAVA TRENCH OUTER-ARC BASIN INDIAN OCEAN Pre-subduction strata, beneath basin sediments, Sea Water OUTER-ARC RIDGE iia on oceanic crusl
5 O 50-
ASTHENOSPHERE
Fig. 2-4. North-south cross-sections across Java Trench and island showing seismic velocities and inferred structure for six sites as indicated on the locality map (modified from Hoshino and Sunoto, 1978; Hanulton, 1979). 159
106° 108° 110° 114° 6°, ' 112° J\ 1 <"V-J 1 JAVA 8° -
Unit: 1 - alluvium 2 = Quaternary volcanic products central region 3 = Pliocene to Pleistocene volcanic products - northern 4 = Neogene sediments _ region 5 = Oligo-Miocene sediments 6 = Neogene andesite southern 7 = diorite-gabbro intrusion (Oligocene - ? Miocene) region 8 = Melange containing mica schist dated at 117 Ma. 9a = active volcano 9b = dormant or extinct volcano. 10 = normal fault. 11 = anticlinorium.
Fig. 2-5. Simplified geological map of Central Java (from Bahar, 1984). 160 •
c
Fig. 2-7. Schematic representation of relationship between Benioff Zone and the Reference Point (RP) which can be formulated as tan 0 = h/d. 0 = dip of Benioff Zone, h = depth of Benioff Zone from the surface, d = distance from RP to the magmatic complex and JT = Java Trench. a)
VZ = 5 cm/year
b)
Quaternary 5 = Merapi 4 = Sumbing 3 = Ungaran 2 = Muria Tertiary 1 = Southern Mts.
52 54 56 58 60 62 64 Dip of Benioff zone (in degree)
Figs. 2-8. (a) Relationship between rate of convergence (V0) and sinking rate (Vz). 0 = dip of Benioff Zone (from Luyendyk, 1970). (b) Rate of convergence between Tertiary and Quaternary in Central Java. Calculation is made by assuming Vz = 5 cm/y. 110" 10
ric r'tri-
no-io
GEOLOGICAL SKETCH MAP OF UNGARAN VOLCANO 0 4km
EXPLANATION
GENDOL LAVA LAPAK LAVA KEMALON LAVA
CANDI LAVA _____ KAPANG LAVA M KEBROK LAVA
COHONG LAVA WRANGKANG LAVA 3 ~| SVANONDO LAVA
UNGARAN LAVA KR1NCING LAVA SUROLOYO LAVA
DA RUM L AVA MEDINI LAVA MUNDING LAVA
SlGUA LAVA PARAMtA_AN L AVA
GEBUGAN LAVA PARASITIC CONES LAVA
CONTACT U FAULT Cnjtt-r rtm LINEAMENT from air photo* and rtmort- t«ntlng Image D • Down thrown ik» U = Upthrcwn .id. doshod wtwre appro-——My locattd or luf-llltl
Fig. 2-9. Geological map of Ungaran volcano (compiled from van Bemmelen, 1949; Thaden et al., Muhardjo et al., 1984). 163
110'10'
7" 10
SAMPLE LOCATION MAP
UNGARAN VOLCANO, CENTRAL JAVA, INDONESIA 0 2 4 I 1 1 KM EXPLANATION
"326 SAMPLE LOCATIONS
RIVER
A 981 ALTITUDE (metres)
VILLAGE
Fig. 2-10. Samples location map from Ungaran volcano. 164
nioou-t.AU PLEISTOCENE niOOLC PLIOCENE
ll^-jlj-liliNioGENI'MARINE DEPOSITS;
LATt PLIOCEN£-EAFILr PLEISTOCENE LATE PLEISTOCENE
EAHLY-MI0OLE PLEISIOCENE LATE PLEISTOCEME-HOLOaHE
J. I
Fig. 2-11. Schematic representation of the evolution of Ungaran volcano (modified from van Bemmelen, 1949). See Table 2-1 for explanation. 165
-—J— Anticline -—$— Syncline rrrrrr Normal fault with fault scarp _^_-. Transverse fault
Segments of the Old Ungaran
0 2 4 6 8 10km • • i i 1 —— r
Fig. 2-12. Chronological succession from oldest (1) to youngest (6) faults around Ungaran volcano (from van Bemmelen, 1941). 166
CO 9 9 o CD O 01 d
> CO ED CO >- Q Q Q _> 2
d co
u. _i CD _:
O) o _• C\J CM o r*~- eg CO o — CM C\J
CL o LU _J 0.
-r o o CN 167
Figure 2-13. Stratigraphy correlation of Pliocene-Pleistocene Formations in Central and East Java. Key: Column I: Geochronology and Boundaries L.PL = Late Pleistocene; M.PL = Middle Pleistocene; E.P1 = Early Pleistocene; L.Plio = Late Pliocene.
Column II: The Magnetostratigraphic Sequences BN = Brunhes Normal; MR = Matuyama Reversed; GN = Gauss Normal; BE = Blake Event; JE = Jaramillo Event; KE = Kukla Event; OE = Olduvai Event; ME = Mammoth Event
Column HI: Stratigraphy of Eastern Java ST= Solo Terraces; NF= Notopuro Formation; KF= Kabuh Formation; PF= Pucangan Formation; KBF= Kalibeng Formation.
Column IV : Stratigraphy of Central Java YV= Young Volcanic Formation; NF= Notopuro Formation; UDB= Upper Damar Bed; MDB= Middle Damar Bed; LDB= Lower Damar Bed.
Column V : Radiometric ages of Muria Volcano 1 - 5 =first to fifth phase of volcanic activity.
Column VI: Evolutionary sequence for Ungaran Volcano 1= growth of Oldest Ungaran; 2 = partly denudation and growth of the Oldest Ungaran, followed by first collapse; 3 = growth of the Old Ungaran followed by second collapse and the formation of parasitic cones; 4 = growth of Young Ungaran.
Column VII: Evolutionary sequence for Merapi Volcano 1 = growth of Ancient Merapi; 2 = growth of Recent Merapi.
1.67 = K-Ai age; *) 0.48 = fission track age; **) 1,2,4 = data sources for compilation of column.
Data sources : 1 = Nillson (1983); 2 = Semah (1982); 3 = Bowen (1978); 4 = Orchiston and Siesser (1982); 5 = Cox (1969); 6 = Smith and Forster (1969); 7 = van Montfrans (1971); 8 = Dalrymple (1972); 9 = Watkins (1972); 10 = Prevot (1976); 11 = Mc Dougall (1978); 12 = Mankinnen and Dalrymple (1979); 13 = van Bemmelen (1949); 14 = Ninkovich and Burckle (1978); 15 = Jacob (1972); 16 = Nishimura et al. (1980); 17 = Batan-Nira (1978); 18 = Thaden et al. (1975); 19 = Wartono et al. (1977). 168
a
Mole%
• groundmass rim
a
MoIe%
core
Ab o 20 40 60 80 100
Fig. 3-1. Feldspar compositions for basalts from Oldest Ungaran. Rim and core compositions are for phenocrysts. 169
Wo
Atomic %
100
# * Diopside
a groundmass Augite • phenocryst Endiopside 40 10 20 30
Fig. 3-2. Clinopyroxene compositions for basalts from Oldest Ungaran.
Fe3+ 0.9 Parg aside Pargasite hornblende 0.8 + 0.7 -ta _- + OXI 0.6 Ferroan pargasitic Ferroan pargasite 0.5 hornblende 0.4 0.3 5.75 6.00 6.25 6.50 Si Fig. 3-3. Compositions of amphibole phenocrysts from basalts of Oldest Ungaran. Fe3+, Al^ and Si are in atomic proportions per formula unit. 170 0.025 0.020" 0.58 0.60 0.62 0.64 0.66 0.68 0.70 Mg/Mg+Fe2+ Fig. 3-4. Olivine compositions for basalts from Oldest Ungaran. Arrows indicate direction of zoning of individual grain . R = rim; M = between rim and core; C = core. Mn is in atomic proportion and all Fe is calculated as Fe2+. MoIe% - groundmass • rim Mole% core 40 60 Fig. 3-5. Feldspar compositions for andesite from Oldest Ungaran. Rim and core compositions are for phenocrysts. 171 Wo Atomic % Fs 100 o groundmass • phenocryst 0 10 20 Fig. 3-6. Clinopyroxene compositions for andesite from Oldest Ungaran Fe>+>A1VI l.U 0.9 1. Magnesio-hastingsitic ^ Magnesio-hastingsite hornblende 0.8 G7 0.7 + • 0.6 Magnesian hastingsitic 0.5 - Magnesian hastingsite hornblende 0.4 1 1 • •( 1 1 1 i i i i „ _.. - 5.75 6.00 6.25 6.50 Si Fig. 3-7. Compositions of amphibole phenocrysts from andesite of Oldest Ungaran. Fe3+, A1VI and Si are in atomic proportions per formula unit. 172 CD E o _: o • • o + ,4) o P-, 03 o a—i ,-3 o oo 13 o PL. < I vo G a-i C/3 IU o VO a-a • _a C/I TJ Can 4—» CO VO C 1) OH cS o o C o O VO in O o U 00 m OO I ' ' ' I • ' ' I ' CN 00 "3- O VD tS OO •<$• © o tN CM -T O # O o c/5 173 Or Mole% - groundmass i ' ia4b 80 100 • rim 40 60 80 100 Cr MoIe% core 0 20 40 60 80 100 Fig. 3-9. Feldspar compositions for basalts from Old Ungaran. Rim and core compositions are for phenocrysts. 174 Wo Atomic % Eh Fs 100 D groundmass Augite / • phenocryst 0 10 20 Fig. 3-10. Clinopyroxene compositions for basalts from Old Ungaran. Fe3+>A1VI 1.0 0.9 Ir Magnesio-hastingsitic Magnesio-hastingsite hornblende 0.8 + • a Cl 0.7 + 0.6 Magnesian hastingsitic 0.5 - Magnesian hastingsite hornblende 0.4 0.3 • 1 1 1__ 5.75 6.00 6.25 6.50 Si Fig. 3-11. Compositions of amphibole phenocrysts from basalts of Old Ungaran. Fe3+, Al^ and Si are in atomic proportions per formula unit. 175 0.66 0.68 0.72 Mg/Mg+Fe 2+ Fig. 3-12. Olivine compositions for basalts from Old Ungaran. Arrows indicate direction of zoning of individual grains. R = rim; C = core. Mn is in atomic proportion and all Fe is calculated as Fe2+. Mole% -3 groundmass • rim core 0 20 40 60 80 100 Fig. 3-13. Feldspar compositions for basaltic andesites from Old Ungaran. Rim and core compositions are for phenocrysts. 176 Wo Atomic % Fs 100 a groundmass • phenocryst 40 Fig. 3-14. Clinopyroxene compositions for basaltic andesites from Old Ungaran. Fe*+>A1vi 1.0 Magnesio-hastingsitic 0.9 Magnesio-hastingsite hornblende 0.8 0.7 + 0.6 Magnesian hastingsitic Magnesian hastingsite 0.5 hornblende 0.4 0.3 _i i _. ' • L. 5. 75 6.00 6.25 6.50 Si Fig. 3-15. Compositions of amphibole phenocrysts from basaltic andesites of Old Ungaran. Fe3+, A1VI and Si are in atomic proportions per formula unit. 177 0.020 0.014 0.64 0.65 0.66 0.67 0.68 0.69 Mg/Mg+Fei+ Fig. 3-16. Olivine compositions for basaltic andesites from Old Ungaran. Arrows indicate direction of zoning of individual grain. R = rim; M = between core and rim; C = core. Mn is in atomic proportion and all Fe is calculated as Fe2+. o Mo_e% Q groundmass • rim n core Fig. 3-17. Plagioclase compositions for andesite from Old Ungaran. 178 Wo Atomic % En Fs 100 Diopside • groundmass Endiopside Augite • phenocryst 10 Fig. 3-18. Clinopyroxene compositions for andesites from Old Ungaran. FeJ+>AlVI 1.0 - Magnesio-hastingsite + 0.9 Magnesio-hastingsitic to hornblende 0.8 r B_ + 0.7 0.6 0.5 '- Magnesian hastingsite Magnesian hastingsitic 0.4 hornblende 1 ' <— 1 1 1 1 a 0.3 1 1 1 i . , 5.75 6.00 6.25 6.50 Si Fig. 3-19. Compositions of amphibole phenocrysts from andesites of Old Ungaran. Fe3+, AlV* and Si are in atomic proportions per formula unit. 179 Ct Mole% El groundmass • rim n core Fig. 3-20. Plagioclase compositions for basalt from Parasitic Cones. Rim and core compositions are for phenocrysts. Atomic % • groundmass • phenocryst 40 0 10 20 Fig. 3-21. Clinopyroxene compositions for basalts from Parasitic Cones. 180 Fe3+ 1 1 • __. 1 • » 1 5.75 6.00 6.25 6.50 Si Fig. 3-22. Compositions of amphibole phenocrysts from basalt of Parasitic Cones. Fe3+, Al^ and Si are in atomic proportions per formula unit. 0.026 0.024- 0.022- 0.020 0.018 " e 0.016 - 0.014 - 0.012 H—'—i—• 1—'—i—•—i—• 1—'—i—•—i—• i—~~ 0.54 0.56 0.58 0.60 0.62 0.64 0.66 0.68 0.70 0.72 Mg/Mg+Fe2+ Fig. 3-23. Olivine compositions for basalt from Parasitic Cones. .Arrows indicate direction of zoning from the core to the rim of individual grains. Mn is in atomic proportion and all Fe is calculated as Fe2+. 181 Or MoIe% E groundmass 80 100 a MoIe% • rim core 0 20 40 60 80 100 Fig. 3-24. Feldspar compositions for basaltic andesites from Parasitic Cones. Rim and core compositions are for phenocrysts. 182 Wo Atomic % Fs 100 t_ groundmass • phenocryst 40 Fig. 3-25. Clinopyroxene compositions for basaltic andesites from Parasitic Cones. Fe3* > Al^ 1.0 0.9 I Magnesio-hastingsitic Magnesio-hastingsite hornblende 0.8 : _? fe 0.7 + to 0.6 Magnesian hastingsitic 0.5 1 Magnesian hastingsite hornblende 0.4 0.3 i 5.75 6.00 6.25 6.50 Si Fig. 3-26. Compositions of amphibole phenocrysts from basaltic andesites of Parasitic Cones. Fe3+, A1VI and Si are in atomic proportions per formula unit. 183 c 0.014 r 0.64 0.65 0.66 0.67 0.68 0.69 Mg/Mg+Fe*"1" Rg. 3-27. Olivine compositions for basaltic andesite from Parasitic Cones. Arrows indicate direction of zoning from core to rim in individual grain. Mn is in atomic proportion and all Fe is calculated as Fe2+. Mc4e% Q groundmass • rim 40 60 Mole% core Fig. 3-28. Plagioclase compositions for andesites from Parasitic Cones. Rim and core compositions are for phenocrysts. 184 Wo Atomic % • phenocryst 40 0 10 20 Fig. 3-29. Clinopyroxene compositions for andesites from Parasitic Cones Fe3+>A1VI i.U • 0.9 Magnesio-hastingsitic 0.8 J•_ Magnesio-hastingsite hornblende 1 + n fe 0.7 + 0.6 0.5 '- Magnesian hastingsite Magnesian hastingsitic 0.4 hornblende . 1 1 • • 1 • 1 . , 0.3 1 _1_ 1 L_ 5.75 6.00 6.25 6.50 Si Fig. 3-30. Compositions of amphibole phenocrysts from andesites of Parasitic Cones. Fe3+, A1VI and Si are in atomic proportions per formula unit 185 Or Mole% - groundmass • rim 0 20 40 60 80 100 a MoIe% core 0 20 40 60 80 100 Fig. 3-31. Feldspar compositions for basalts from Young Ungaran. Rim and core compositions are for phenocrysts. 186 Wo Atomic % Fs 100 • > % Salite • groundmass • phenocryst Augite 40 Fig. 3-32. Clinopyroxene compositions for basalts from Young Ungaran. Fe3+ 0.4 0.3 JL— .— • •— t— 6.00 6.25 6.50 5.75 Si Fe3+>A1VI 1.0 0.9 Magnesio-hastingsitic : Q 1= hornblende 0.8 a Magnesio-hastingsite 4 _t 0.7 ta i + - to 0.6 Magnesian hastingsttic ._- 0.5 - Magnesian hastingsite homblavie 0.4 0.3 5.75 6.00 6.25 6.50 Si Fig. 3-33. Compositions of amphibole phenocrysts from basalts of Young Ungaran. Fe3+, Al^ and Si are in atomic proportions per formula unit. 187 o8 o _ -ac— 6 «ob 00 -1-c^ c oN <*-. o c a_o» _ + =1e_ u 00 a__* fe C3 cH Ha 3c_ •^cH a—> CO 3 O g o 00 < • —a • feo £ 53 "c3 W3 -o c c W) •ao c3 i- o a a ii 2 o oo •g a_i o oo C. C -0 • ?_i l— oo •—H o C CoSo C s .o 00 "a—> C .to — < "ja o feb 6ex , «—H o 3 o -•f-aH u > c .=53 > •+-i o o Tr 6 co CO •oc • J3 fe "IM 188 a Mole% • groundmass • nm core 0 20 40 60 80 100 Fig. 3-35. Feldspar compositions for basaltic andesites from Young Ungaran. Rim and core compositions are for phenocrysts. 189 Wo Atomic % En Fs 100 • groundmass • phenocryst 40 Fig. 3-36. Clinopyroxene compositions for basaltic andesites from Young Ungaran Fe3+>A1VI 1.0 r 0.9 Magnesio-hastingsitic Magnesio-hastingsite hornblende 0.8 + : _P 0.7 fe + 0.6 Magnesian hastingsitic 0.5 - Magnesian hastingsite hornblende 0.4 Jr 0.3 5.75 6.00 6.25 6.50 Si Fig. 3-37. Compositions of amphibole phenocrysts from basaltic andesites of Young Ungaran. Fe3+, A1VI and Si are in atomic proportions per formula unit. 190 Mole% • groundmass • rim n 20 40 60 80 100 Mole% core 0 20 40 60 80 100 Fig. 3-38. Feldspar compositions for andesites from Young Ungaran. Rim and core compositions are for phenocrysts. 191 Wo a4tomic% Fs 100 • groundmass Augite / • phenocryst i | i 0 10 20 Fig.3-39. Clinopyroxene compositions for andesites from Young Ungaran. F^+>A1VI l.U I 0.9 Magnesio-hastingsite Magnesio-hastingsitic hornblende 0.8 : Q + 0.7 • i 1 fe \ + 0.6 Magnesian hastingsidc 0.5 Magnesian hastingsite s hornblende 0.4 i i i 1 • * i* * i • • • 5.75 6.00 6.25 6.50 Si Fig. 3-40. Compositions of amphibole phenocrysts from andesites of Young Ungaran. Fe3+, A1VI and Si are in atomic proportions per formula unit. 192 CD E o •— u + B • CN C o c o '.£ 'oo oO U(X i co OO fe I • I I ' • I « • ' I ' I ' ' ' I I I I ^ O VO (N OO •^ o ^O CN OO o TJ- ro m cs (N CN o # O o 193 MoIe% a groundmass • rim core 0 20 40 60 80 100 Fig. 3-42. Feldspar compositions for basalts from Ungaran volcano. Rim and core compositions are for phenocrysts. 194 a Mole% E groundmass • rim core 20 40 60 80 100 Fig. 3-43. Feldspar compositions for basaltic andesites from Ungaran volcano. Rim and core compositions are for phenocrysts. 195 Mole% Q groundmass 20 40 60 80 100 MoIe% • rim 20 40 60 80 100 MoIe% • core 0 20 40 60 80 100 Fig. 3-44. Feldspar compositions for andesites from Ungaran volcano. Rim and core compositions are for phenocrysts. 196 0- Basalt 9- 8-] 7- 6- m 5- .z-z. Z.Z;* 4- Z:Z 3^ 'm, ? - :->:':'• '.' " ;•'.:" :M . Z.-:"' ':';: '':: - :•'•;•:• •;>:>;:;. 1 n , .' • •:•:>;.• '•:•:•:•::•:-:• : ••>':•: •:•;•:•:•.. '• • 2530354)455055606570 75 80859095 Midiile o finti:rval (A n mole %) 10 9 Basaltic andesite 8 :, 7 6 5 4 I 3 : 2 1 1 •-.•:••- I 835 J 0 I 2530354045505560657)75 85 90 95 Middle of Interval (An mole %) 25303540455055606570 75 85 90 95 Middle of interval (An mole %) Fig. 3-45. Histogram of anorthite content for phenocryst cores from Ungaran volcano. 197 Oldest Young Ungaran Ungaran © E c < Oldest Old Parasitic Young Ungaran Ungaran Cones Ungaran Oldest Old Parasitic Young Ungaran Ungaran Cones Ungaran Fig. 3-46. Plot of time versus composition of cores of plagioclase phenocrysts from Ungaran volcano. 198 Wo Atomic % En 0 10 20 30 40 50 60 70 80 90 100 • groundmass • phenocryst Q groundmass • phenocryst 199 0.05 0.04 - 0.03 S (a) TV4 + 0 0.02 Q O 0.01 - • 0.00 Basalt Basaltic andesite Andesite 0.04 0.03 - (b) Ti4+ 0.02 0.01 - 0.00 Diopside Salite Augite 0.05 0.04 - 0.03 - (C) Ti4 + 0.02 0.01 - 0.00 Fig. 3-48. Plot of Ti4+ (atoms per 6 oxygens) in clinopyroxene from Ungaran against (a) rock types, (b) phenocrysts composition and (c) core-rim composition. 200 0.400 (a) 0.300 aAJIV 0.200 0.100 o.ooo Basalt Basaltic andesite Andesite 0.300 (b) 0.200 - Alr v 0.100 - 0.000 Diopside Salite Augite 0.400 (C) 0.300 - AF 0.200 0.100 - 0.000 Core Rim Fig. 3-49. Plot of A1IV (atoms per 6 oxygens) in clinopyroxene from Ungaran against (a) rock types, (b) phenocrysts compositions and (c) core-rim composition. 201 (a) AJ " 15 - • £ 0 E o D > 10- 1CD G • c _• E _ CU • X _ oCL , • O 5 J E E aQ U • • P 0- ' _ I 1 Basalt Basaltic andesite Andesite (b) Oldest Old Parasitic Young Ungaran Ungaran Cones Ungaran Fig. 3-50. Plot of modal data for clinopyroxene from Ungaran voleano versus (a) rock type and (b) time. 202 0.19 - y = 0.0066+ 0.1762x; r = 0.66 _n 0.09 - 'S ~ la , - _— n = 107 iiffm-nimi-a cn __r__] n -0.01 0.O 0.1 0.2 0.3* 0.4'. Airv 0.05 y = - 0.000006 + 0.1208x; r = 0.96 0.04 - __ < 0.29 - y- 0.0143 + 0.5808x; r = 0.78 0.19i + <_> ts. 0.09 - DCP^P<_ • tm a t_ n- 107 -0.01 • < '—• • i i i | i i i i i i ______a -—-——-1—i—i—i—| i i i i i i , , 0.0 0.1 0-2 0.3 0.4 AHV Fig. 3-51. Plot of A.™ versus AlVl, Fe3+ and T.4+ (atoms per 6 oxygens) in clinopyroxene from Ungaran showing regression line and the equation (r = correlation coefficient, n = number of observations). 203 Andesites 0.05 y= -0.0015 +0.1112x; r = 0.98 0.04 -. n = 26 • • i i i i i i i i i i i i i » 0.4 Basaltic andesites 0.05 y = 0.0002 + 0.1293x; r = 0.97 n = 23 • i i i i i i i i i i i i i 0.2 0.3 0.4 AUV Basalts 0.05 y = 0.0006 + 0.1504x; r = 0.96 0.04 j 0.03 i n = 60 i i i i i i i i i i i i i i i i i i i i i i i f I P IT 0.1 0.2 0.3 0.4 AUV Fig. 3-52. Plot of A1IV versus A1VI (atoms per 6 oxygens) in clinopyroxene for each rock type from Ungaran, showing regression line and the equation (r = correlation coefficient, n = number of observations). 204 50 "J • • 40 • • • • PI 0 g • @ E 30- 20 Oldest Old Parasitic Young Ungaran Ungaran Cones Ungaran 20" p • 1 • a n 1 • 10-j I B • s Q • o- i Oldest Old Parasitic Young Ungaran Ungaran Cones Ungaran 4 _ 3- • B _ B 2" B • O n B to 1 t_ Q 1- • • • a • o- • • Oldest Old Parasitic Young Ungaran Ungaran Cones Ungaran Fig. 3-53. Plot of time versus major element compositions of Fe-Ti oxide from Ungaran volcano. 205 oC3 cd ^ 3> C cd 53 bO Dc S VoH « an M \ o ol-l fe l-l + t4oH 00 ex c .—oa •— .—H 00 O Q* + Oa r* o rU in fe oo *_oo» cd & T3 O a~CO» o cd _ r—31 J=! O f-H 13 cd o oo o .—a <+H fe O 1—< 00 < a 40 60 80 100 groundmass % % 16 40 60 80 100 groundmass % -r 60 80 100 40 groundmass % %12n o % o 8- • \ CD • \ is n 6- # X * \ e • \ < o # H 4- * * **\ \ CD • \ LL 2- • \ 60 80 100 40 60 80 10( 40 groundmass % groundmass % Fig. 3-55. Plot of modal phenocrysts versus groundmass in order to determine order of crystallisation of lava basalts from Ungaran. Two possible sequences are : a. olivine - plagioclase - clinopyroxene - Fe-Ti oxide - amphibole. b. plagioclase - clinopyroxene - Fe-Ti oxide - amphibole - olivine. 207 % 35-, % 12 __ 25 o o o c CO o> X ra 28 CL 15- 60 80 100 >. a groundmass % O o 4- c i i 1 1 r —i— 40 60 80 100 groundmass % % 12 o 100 ^8 groundmass % E < 4- % 60 80 100 groundmass % • o 1.5 CO __ 1.0 0.5 60 100 60 80 100 groundmass % groundmass % Fig. 3-56. plot of modal phenocrysts versus groundmass in order to determine order of crystallisation of basaltic andesites from Ungaran. The sequences is olivine - plagioclase - clinopyroxene - Fe-Ti oxide - amphibole - mica. 208 % o o cn TO 40 60 80 100 groundmass % % 12 % 12 n o a I 8 O E < 4- 4- -r T" 60 80 100 40 60 80 100 groundmass % groundmass % % 12 %3.0 c CO 2 8 oZO >. CL O C 1.0 O —i— 40 60 80 100 60 80 100 groundmass % groundmass % Fig. 3-57. plot of modal phenocrysts versus groundmass in order to determine order of crystallisation of andesites from Ungaran. The sequence is plagioclase - clinopyroxene - Fe-Ti oxide - amphibole - mica 209 Andesites 0.15 0.10- M VI 0.05 Igneous rocks 0.00 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 Al™ Basaltic andesites Al™ 13 groundmass • rim X core Igneous rocks r**"x_ ° 0.00 ' ' ' ' I ' • • ' . • ' • • i • i • i | n • i | i • i i • • i I i • i • 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 Al™ Basalts 0.15 0.10 AJVI 0.05- r)J S Xp * Igneous rocks 0.00 l i i i i I i i i i I I ' ' • • I 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 AlVI Fig. 3-58. Plot of A1IV versus A1VI (atom per 6 oxygens) for each rock type from Ungaran. Pressure fields from Aoki and Kushiro (1968). 210 Fig. 3-59. Compositions of clinopyroxene phenocrysts from Ungaran volcano. Wo, En and Fs values were calculated using the method of Lindsley (1983). The 500°C and 600°C isotherms are excluded from portion of the quadrilateral. 211 W B c o ID JS C oo •—a o 13 in Id C JD R O R u r^ <4-l U O oo sO <* CN o oo sO ^J- (% T^_) OCT 212 1.1-7 a o + LO-; _P na + • • 0.9-i • • • Young Ungaran f 0.8-i •KV • O Parasitic Cones o «_ + Old Ungaran • D 0.7-= D Oldest Ungaran o°# + • 0.6-i 0.5 • | II in II m i> u i n II 11 m u n m u | II in u n | II n i n m n n i II M 4850525456586062 Si02 (wt%) 21: + U + 20- • • o • • • • n + • • Young Ungaran 19 -j + + • o Parasitic Cones • • • • j O • + Old Ungaran < • •<- • D Oldest Ungaran o 18 : 17 -j 48 50 52 54 56 58 60 62 S102 (wt%) 11 •_ • 10 •: i 9i •* •% + + tf # + o* ai 8-i • Young Ungaran o Parasitic Cones O V _: + + Old Ungaran 7-i • Oldest Ungaran • H • • 0 6-i • J ~l IIII1II II1IIII1II1111 1II1 IIII ] IIII1IIII 1IIII1II1 I "Tin1 II1IIII1 IIII 48 5052 54 56 58 60 62 Si02(wt%) Fig. 4-2. Marker diagrams from Ungaran volcanic rocks. 213 0 ; • 3 5 • O '. a D* 4 •j ; •#• o o • Young Ungaran D .+ • + - O Parasitic Cones 3 _ + • ft<5_ + Old Ungaran = oft_""« • • Oldest Ungaran • 2 +• • 1 " .... •• 1 'f prii.IT •n-f 11 11 i • i 111 48 50 52 54 56 58 60 62 S102 (Wt%) U.JU - 025-. O 0.20-; •a + • + • • • Young Ungaran • O • • O Parasitic Cones +• M -th + •-_• • • • + Old Ungaran a + • • oa_ • £3 Oldest Ungaran 0.15: • • • + D o o-a • • o _• • • • U.10 -j rr 111 11 l n 11 [ n 11 ]1111111 II [ 1111111111 48 50 52 54 56 58 60 62 Si02(wt%) • Young Ungaran O Parasitic Cones + Old Ungaran D Oldest Ungaran 54 55 58 60 62 Si02(wt%) Fig. 4-2 (continued). Harker diagrams from Ungaran volcanic rocks. 214 4.5' 4.0-: OH 3.5-! + *. ;° J- °'- _ • Young Ungaran 3.0 + + O 0 ^pB • o Parasitic Cones + • # •"> + Old Ungaran 2~H -tf Q Oldest Ungaran 2.0 15 ^IIII in n | u n in II |ii iiiiiii|""'""l" "'" "I" " '" "l 4850525456586062 Si02(wL%) • . • _..*• ^ a • • • _r_ #Ho • Young Ungaran a + O Parasitic Cones o + + o • 0 + Old Ungaran 2- 0 Oldest Ungaran 1 - n II i n II [ u M iii n |II u in II HIIIHIIIIIIIIIIIIIIIIIIIIIIIIIMIIII| I 50 52 54 56 58 60 62 Si02 (wt%) u./ - 0.6 i • o 05-= • : • ; o • Young Ungaran 0A-. 1 • "b o Parasitic Cones • %m • urn + Old Ungaran 0.3 -j o _F* _r D Oldest Ungaran + + g • • a • ° o • o • 0.2 -j • • 0 1- II T IIIT JTTTI 1 II II | II II I II IrrTTiI m TTT-J-II n i II u 50 52 54 56 58 60 62 Si02(wt%) Fig. 4-2 (continued). Harker diagrams from Ungaran volcanic rocks. 215 Fig. 4-3. CIPW normative mineralogy for basalt from Oldest Ungaran. • analysed Fe203/FeO+ Fe203 ratio. O Fe^/FeO-i- Fe^ ratio of 0.2 10' Andesites -Q- Basalt (921) -•- Andesite (930) _ 10 2_ '£ •a a o Q __ a. E 1 £ 101 l 10 -, , , , , ! , , -_ T 1 1 r 1 1 1 T La Ce Sm Eu Gd Yb Lu Fig. 4-4. Rare earth element patterns for rocks from Oldest Ungaran. 216 921 925 926 929 930 i i i .. 1 . , J 63- 56 - i 2 V - 00 4& -[ _ - , . ,. i i ' 1 Fig. 4-5. Plot of major element compositions versus time for rocks from Oldest Ungaran. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. 217 ON O CN O Onv # o uo O 2 Fig. 4-5 (continued). Plot of major element compositions versus time for rocks from Oldest Ungaran. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. 218 930 £ 18U ~ 160- & 140- 120 -J inn — i 1 i i i 1 2 3 4 5 Time Fig. 4-6. Plot of trace element compositions (in ppm) versus time for rocks from Oldest Ungaran. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. 219 NO ON C_N- C _- Time Fig. 4-6 (continued). Plot of trace element compositions (in ppm) versus time for rocks from Oldest Ungaran. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot 220 vO ON CN CN ON CN e_ a X o u c o u c o c E < Fig. 4-7. Plot of modal mineralogy (in volume %) versus time for rocks from Oldest Ungaran. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot 221 a c c D o 6 p cd oo cd X> 2 CN o o o V(_ Q o 2 o tU + •a c O t) 2 CO > m • *H t—' o PH o •o + o oo O u >> 13 o oo PH I o O c9'A/ 222 10' Andesite -Q- 924 102d 10 10' T 1 1 1 1 1 i 1 r— -i 1 1 1 1 1 r La Ce Sm Eu Gd Yb Lu io- Basaltic andesites -S- 820 -•- 922 10 2. 101, 10' T 1 1 1 1 1 1 i i 1 1 i 1 1 i 1 r La Ce Sm Eu Gd Yb Lu KZT Basalts -O- 918 -•- 826 -O- 832 KZ-: -*- 823 10^ 10' "i i i 1 1 1 1^ 1 1 1 1 1^ 1 1 1 1 r La Ce Sm Eu Gd Yb Lu Fig. 4-9. Rare earth element patterns for rocks from Old Ungaran. 223 CN O 0.21 0.20 0.19 3 0.18 0.17 0.16 0.15 0.14 1.1 i.o -r 0.9 S P 0.8- 0.7- 0.6 i ~ 12 3 4 5 6 7 9 10 11 5 4 I 3 2- ~ i i 1 1 1 1 1 1 1 r 12345678 9 10 11 Time Fig. 4-10. Plot of major element compositions versus time for rocks from Old Ungaran. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. 224 OO vq —•*_. x "\ 9 - v, N- \ v S N 'PL \ \ Si N / *»vN -. ^^s. \ \ \ y / \ _- \ / s \ \ 8-i N- „ s \ \ X s \V —1 ' A\ \ \ \ \ * _"V / _ I 1 I 1 1 J 1 1 ! 1 I 7 8 9 10 11 10 11 4 -r O 2 CO o Time Fig. 4-10 (continued). Plot of major element compositions versus timefor rocks from Old Ungaran. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. 225 OQ vo 2 Pi R CO CN CN CN CN S ON OCN O0O4 OO OO OO ON ON ON i 1 1 1 1 1 f 1 1 1 1 1UU - *- "N 90- ^_ - s. f 1 80 - \t*L *^ Z /' / \ X •v. ' - , / / / JO 70 - *""-EL N C_ 60- ' / J i tr ' 50- ^ —* - ^* -X *'/•-~'C\/ y r 40- vr S) "1 1 1 1 i i i i i i i 1 1 2 3 4 5 6 7 8 9 10 11 /UJ - a>-^- ». ' /T 1 y / / ' s Fl ) 600- / / ) to / / / MXH y /// **"y / / / \ ^'7T- ' / f • I"'^ • d /J s' 1 / / ** *-* \_ * - **- • - -T —*- " 1 1/ -« **• PI\ k I 1 111 1 1 1 i i " i i . 1 1 r 9 10 11 200- / "> 180; n /// 160; N / //' 'Ba ^'"rj /- /'' 140; s N. _mro-_ / ' \ .' J* s ' 1 ' f_" • ' 1' 120; \ s / ' _—-o/ 1 i i i i 100 -|r. .__ ,...,,_ , A/' I 12 3 4 5 6 7 8 9 10 11 Time Fig. 4-11. Plot of trace element compositions (in ppm) versus time for rocks from Old Ungaran. The time intervaFbetween formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. 226 r- oo vo CN C^l O CN C") Tf 2 8 ON o) CN cn CN CN CN CN CN OO 00 ON ON ON oo ON OC OO > Time Fig. 4-11 (continued). Plot of trace element compositions (in ppm) versus time for rocks from Old Ungaran. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. 227 CC s£> 82 2 0\ 00 ON 0\ ON 82 3 82 0 83 2 -91 8 - -92 7 • 30 • • 28 J _^ — "* N ** **-N 26 _> — / H / f\ n 2. •v \ v V - * / 22 \ \ V o / / ^ \ ^ « 20 *- ' / 18 * 1 Z- 16 1 1 i i i 1 1 1 2 3 4 5 6 7 8 9 10 11 16 14 _i 12 c <_ 1C - tl X 8 \ -X'' c _r s —. 6 ' M ' ". . \- N c N 4 N> \_ o N Fl • c 2 ** _ ., 1 I i I I i 1 1 u 1 2 3 4 5 6 7 8 9 10 11 v) S v. JT o 7 V \ X 6 N ^ ^\z c \ H \ _ • 5 * —• N H \ \ v __ / 4 N. \ [_. zir '' 3 v J^. 2 1 1 I i i 1 1 I 1 1 "I 1 2 3 4 5 6 7 8 9 10 11 3.0 2.5 _ 2.0 ca 1.5 C \ \ \ \ Vi s > 1.0 -. Z>CLZ-- - - — J^l < \ N 0.5 O v *- — ~ - — 0.0 ** _' 1 1 1 1 1 i i i 1 1 1 1 2 3 4 5 6 7 8 9 10 11 5-5 - 4.5 C 3.5 _ / _ 2.5 E 1.5 < / 0.5 ' /\ /° 1 1 I i i 1 1 i i 1 1 1 2 3 4 5 6 7 8 9 10 11 40 " 44 -_ 42 •; CJ) 40 - 38 ^ 36 : 34 -J i i 1 i i I 1 i 1 1 I 2 4 6 8 10 Time Fig. 4-12. Plot of modal mineralogy (in volume %) versus time for rocks from Old Ungaran. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. TPC = total phenocryst content. 228 10" Aiuiesitcs •O- 429 -»- 919 o 10 2_ 'u. •o 3 u _2 c S S 10' 10 ui 1 1 1 1 r i i i i i i i i i i r La Ce Sm Eu Gd Yb Lu 10" Basaltic andesites -Q- 428 -•- 425 _• 10'- c o y _i c S 10 io i i i 1 1 , j ] ,- , , p -i 1 1 1 r La Ce Sm Eu Gd Yb Lu 10' Basalt -O- 917 o 102- c o U oo 10 Z v 10 T I 1 I I I 1 1 1 1 , , , 1 , , p La Ce Sm Eu Gd yb Lu Fig. 4-13. Rare earth element patterns for rocks from Parasitic Cones. 229 ON <_> ^S oo I— la") TT CO o\ CN CN CN CN CN CN O 0.26 0.24 0.22 0.20 0.18 0.16 0.14 1.1 1.0 0.9 0.8 2 c- 0.7 0.6 0_5 "T" —\ r 2 10 11 21 20-| n O 19 CN 18 17 T 1 1 1 i 1 1 i i ' r 123456789 10 11 4- S 3H —i j 1 1 1 [ I I l i i 1.2 3 45 6 78 910 11 Time Fig. 4-14. Plot of major element compositions versus time for rocks from Parasitic Cones. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. 230 _ o <_ 1c 11 10 9 Q O 8 H 7 6 -i 1 r 9 10 11 LO o s Time Fig. 4-14 (continued). Plot of major element compositions versus time for rocks from Parasitic Cones. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot 231 ON vo oo "* n ON CN! CN JO §oa •xT •xt __ CN — •* ->cr ON 100- I I _ 1 1 1 90 • 700 600- 500- 400 l 1 1 1 r 7 8 9 10 11 180- C1* 160- /x \ - / \ \ x v / \ s \ > \ 1I \ V -x. ^ > s. X. _/ 120- - \ \ j- / V \ ^^ - / \. tj_r . _ / 1UU -| i i i i 1 1 1 II 1 1 12 3 4 5 6 7 8 9 10 11 Time Fig. 4-15. Plot of trace element compositions (in ppm) versus time for rocks from Parasitic Cones. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. 232 S CN" =5 S P. a £ CN g (N XT "xt "xt r= 10 ~i 1 r ___ —r 1 2 3 10 11 20 15 _ a£ 10 -• ~I 1 T" 9 10 11 60 50 40 30 - 20 Time Fig. 4-15 (continued). Plot of trace element compositions (in ppm) versus time for rocks from Parasitic Cones. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. 233 Time Fig. 4-16. Plot of modal rnineralogy (in volume %) versus time for rocks from Parasitic Cones. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. Dashed lines indicate groups defined on the basis of major element data. TPC = total phenocryst content. 234 o e O CO o o o fa-, •*_ + 2 CO o o CO ft, ft, + •8 00 oCl cv3 rv) S £ • o "xf 235 io- Andesites 10 *-. 10 l: l 10 "T i I i i i i 1 1 1 1 1 1 1 1 i r La Ce Sm Eu Gd Yb Lu 10- Basaltic andesites 102- lO1^ v 10 T 1 I 1 1 1 1 1 1 r -i 1 i 1 1 r La Ce Sm Eu Gd Yb Lu KZ-r Basalts 10 2_ 10 ^ l 10 T I 1 I 1 I 1 I 1 1 1 I 1 ' ' I T La Ce Sm Eu Gd Yb Lu Fig. 4-18. Rare earth element patterns for rocks from Young Ungaran. 236 OSSBSB883S8I388311O 00 00 00 00 00 00 xt oo m 5 339883 8258§5 J I I I I II I I I _ c_ I I I I I I I I I I I I I I I -acNco-tvnNor~ooc>o-aa-tast222;a^Fxa^««cNS«R o r-1 a Z I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I o CN Ua -i—r~i—i—i—i—•—i—i—i—n—i i i—i—n—i i i i—i i i—i—i—i—i—r -N-^m^r-ooovg-pji-jvigrjgjj^-jpjjq^jq^^^jNN^ O OS U I I I I I I I I I I I I I I I I I I I I I I—I I I I I I I I •" I I I I I I I I I I I I I I I I I I I I , , , i '^^"^^^^"^2san3asfc2as^NR^c<3«p5?xR)S Time Fig. 4-19 (continued). Plot of major element compositions versus time for rocks from Young Ungaran. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. 237 lNS»Sfi88 3R8isaaa§8E,SSHaS.a cissa• ._. co «og ro CO 00 -ct •* "J -st o i ' i' i i i i i i i i i i r r i i i i i i i i i i i i i i i i -CNcO-t.OVOt-.OOCNO-acO^^a^Ma^^^gN^^NQp.jggj^ 0.22 ~I—I I I I I I I—I I I I I I I I I I i i i i i i i i i i i i -CNacorfv^voc-cao^o-Nco^^^^^^^-a^gj^^^p-^gN^ I I I I I I I I—I I I I I 1 I 1 I I 1 I I I I I I I I I I' I -CNcO-tV,VOt-_C>S-;aaS^S&Mac^SpJpN^^^p5?ggi^ rO o r-1 [Till III I I I I III III I I I I III I I I I -CNCO-*vc,voi-<»^2-adasaSfc23RcNacxlNScxl«P5KgiS O =_ S i i i i i i i i i i i i i ' i ' ' -cxiCNO-tv.vDr-oo^S-aa^aS&SaR^c^RSW»Pj89?aS. Time Fig. 4-19. Plot of major element compositions versus time for rocks from Young Ungaran. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. 238 o\ o 3 oN OO VO (SM CNJlTi 1—i i i i—i i i—r i" i -HCNCO^^VOr-COC^g-H^Q^^vo^^g^-^pJjq^^jVg^^gjcq -i—i i i i—ill—I I I I—I I i—i i i—> i i i r ^CNcOrt^vo^oOONO^^a^^vo^^^^j-j^pj^^vg^^^^ i i i i i—r—r-1—i i i i—m—r-m—i i i i—r~r~i—i i i T i i i i i i i r i—r I I I—i i I—I I i I—I I I—I I i i—r --iCNcO'xtV-lvor^OOONO'-iCN S3»S£238CN,CN183C Fig. 4-20. Plot of trace element compositions versus time for rocks from Young Ungaran. The distance between each sequential number in time is constant. Clusters represented by dash line. In sequence, thefirst cluste r is in the left and the last cluster is in the right. 239 ix-ifx3 _ ~—iiii—r-T~i—i i ii—r—r—i—r—i—i—i i i i—r~r-i—r ( . i r i i i i—i i i—i" i" r i—III—i i i—i i i i—in—r i II—r -aCNrOV^VOIxoO^OsaQSajO^OJOja^jNljq^jCJ^^^^S -f—i i i i—i—r—i—i i i I—r-n r—r-1 i i i i r—r—i r Time Fig. 4-20 (continued). Plot of trace element compositions versus time for rocks from Young Ungaran. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. 240 ' VO _ S _,r-oovocNooco N £3 >0 St co SSt; SSSS^SasasassN OO -xf OO CO CN s "xt^-xt-xt-xt-xtCO-xt -xtcOOO-xt ^G^ 1 I I I I • 1 J-J I I I V tSl 3 sx rs I I I I I I I I I -HC-^co-xtvovor-oooNQ -23SaSC22R?3ciaS«ScsS?lS 4) 'x o I I I I—I I I I I I I I I I—II I I I I NcOTfLovoi-<>ooNO^^co3vNOr--oo2^p;f|^^^^p5^gJ^ T—I—i—r—i—i—r-1—i—i—i—i—n—i—i—i—i—i—n—i—i—i—i—i—i—i—r~r- i i i i i—r i i i i i i i i i—i—i i i i i i i i i—i i i i i ^^COTt^VOt-CC^g-Hy^^^^^^^^^^jq^^^p-^gj^ Time Fig. 4-21. Plot of modal mineralogy (in volume %) versus time for rocks from Young Ungaran. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the plot. 241 ^3 2^ w*0 NCO cs _3v>-xtco cjv< t-- COCaOOOCaOaDOOOO^WCn^^cOCO-xt^-xfTt-^-xtTtCO^xCaO OO OO CaO — ' ' - -• ' ' -t '"x t •— Oico CO QOO Jo I CO00 -xt "*<3 -xt i i i i i i i i i i i i i y i c saaaasasaRScNNScQ^ficiSS r IIII—i i i i i i i i i i i i i i i i i i i i i i i i i I I I I I I I I I I I I I I I I I ' Time Fig. 4-21 (continued). Plot of modal mineralogy (in volume %) versus time for rocks from Young Ungaran. The time interval between formation of each unit is assumed to be constant and the sample numbers are shown at the top of the ploL TPC = total phenocrysts content 242 o c « o -• . bX) r—« c? c __ a ca f > lilillllilllillliliilili:ii:iliilli o _\ e_o>. O ?#i"::'' T3 :^|;:>. •-$;&. ON •o CO :; ; ^v ;4r yi>iil;ij;iii5f o 3 1 oq ill illllll O -? o t-- C+H o o 5b o _ p iitiit o o 2 4 © i 1 1 1 1 ' • 1 ' 1 ' i > 3 5J O VO o oo vo TT N _J 3 3 r-H fouanba.y 243 12 SiQ2 10 >> 8 w a a o< 6 a> :¥¥¥¥: C-i I 4 4950 51525354555657585960 61 Middle of interval (wt %) 20 18 A12Q3 16 14 >> a 12 OJ 3 10 clar :":•:•:•:•;•:•:•:•:•: C-4 8 1111 6 S¥S¥H ••>:•:•>:•'.•: W#&: mwiwjj 4 mmm ill!! 2 mmm 0 mmm 17.6 18 18.4 18.8 19.2 19.6 20 20.4 20.8 Middle of interval (wt %) 10 TiQ2 li III s 6 mW 3 cr 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 1.05 1.1 Middle of interval (wt %) Fig. 4-23. Histograms of compositional frequency for major element oxides for rocks from Ungaran volcano. 244 15 FeO* >» 10 -\ c 3 cr 5- _i 6-5 7 7.5 8 8.5 9 95 10 m10.l5 Middle of interval (wt %) 20 18 - MgO 16 - 14 s 12 Ol O" 10- _- mm mmi. 8&M iil. ;:¥5«¥>: 3.5 4.5 5.5 Middle of interval (wt %) u. - CaO 10- £¥:¥:$:¥: ^SlpS fill! ' >> 8 - :j:^g|J¥. yss'.N.. CJ : : : G •'¥'•¥:::.¥: !¥> ¥: ¥:. :¥:&:¥:¥: .-.v. .v.-- Ol ;•:•:•:•:•: :•;•: ,. & 6- ; ' •.'• :¥:-'•'.¥:¥:'• ' 0> : : ::' -• • mm< : 'v • illlll '¥ .vZv _- '<$$%& WMp& .: :¥:¥•: :'.- : •:¥:¥&¥:¥ 4- W0-• S* ¥3s?: gglpg '$0&.ZZ' : " ¥:¥:¥¥•¥ 2- III • ' • ill&llll ; Wnm ' itll mwm\ '• , • "' : •""' • • o-l ______5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 Middle of interval (wt %) Fig. 4-23 (continued). Histograms of compositional frequency for major element oxides for rocks from Ungaran volcano. 245 u - Na20 10- >N >> 8- U \^N -'; llllllll S S V iiit; __ - lltllli 4- §1111 i§tii§ N 2- ¥ - lllll jllli ,Y V o- I ' " "'''''''i i 2.2 24 2.6 2.8 3 32 3.4 3.6 Middle of interval (wt %) 20 18 -I K20 16 14 -| >» :¥:¥:¥*¥ _! 12-| mm §.10H £ 8 6H ::¥:¥::¥:i¥' 4 2H 0 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3.2 Middle of interval (wt %) 20 P205 18 - nj^mjjFiwi^ 16 - 14- S n-i —WTOT7I-TT £ 8 6- 4- 2 0 0.2 0.25 0.3 0.35 0.4 0.45 0.5 Middle of interval (wt %) Fig. 4-23 (continued). Histograms of compositional frequency for major element oxides for rocks from Ungaran volcano. 246 800; + •to • o 600- • O . • ++ + . " • • • Young Ungaran E • O • + • •• __ on O Parasitic Cones c_ + • + Old Ungaran u + D 400; • • Oldest Ungaran • 200 - rrj-i- ...... 50 52 54 56 58 60 62 Si02 (wt.%) Fig. 4-24. Plot of Sr against Si02 for rocks from Ungaran volcano showing three different clusters. Basalts have widest range of Sr content compare with basaltic andesites and andesites. The correlation coefficient (- 0.327) is significant at the 95% confidence level (Table 4-20). 700 600- + aA_.desite E • Basaltic andesite E- 500- e_ • Basalt in 400 300 180 Fig. 4-25. Plot of Sr against Ca/Sr for rocks from Ungaran volcano showing regression lines (indicated by arrows). The correlation coefficient for basalt (0.91) is significant at the 95% confidence level. 247 • Young Ungaran O Parasitic Cones + Old Ungaran • Oldest Ungaran 54 56 58 60 62 Si02(wt.%) Fig. 4-26. Plot of Rb against SiC»2 for rocks from Ungaran volcano. The correlation coefficient (0.693) is significant at the 95% confidence level (Table 4-20). 3.0 2.5- + .Andesite -x 2.0- • Basaltic andesite • Basalt 1-5 1.0- 0.5 Fig. 4-27. Plot of K against Rb for rocks from Ungaran volcano. The basalts have the widest range of K/Rb. The correlation coefficient for all samples (0.70) is significant at the 95% confidence level. 248 80 T 75 •. 1 70 •; —D— 2 65 - a—t 3 a 60 - CO 4 R5 55 - .a 50 - 5 L. o 45 - 6 -o— 40- — o— 7 s 35 -. --__-- 8 C3 _ 30 - o 25 - __ 20-i CJ • ft.o 15 - 10- 5- 0: Sr K Rb Element Fig. 4-28. Sr - K - Rb variation diagram of rocks from Ungaran volcano and elsewhere. All rocks are normalized against the value of ocean floor basalt. (1) = oceanic floor basalts (Hart et al.,1970); (2) = island arc tholeiitic (Jakes and White, 1972); (3) = calcalkaline andesites (Jakes and White, 1972); (4) = high-K calcalkaline basalts (MacKenzie and Chappell, 1972); (5) = high-K calcalkaline andesites (Ewart, 1982); (6) = average value of basalts from Ungaran volcano; (7) = average value of basaltic andesites from Ungaran volcano; (8) = average value of andesites from Ungaran volcano. 249 _5U - • • • • 20; • • a • • s • • • o o D • Young Ungaran a. o + + O • • • o + • • + O Parasitic Cones _ - • • • • D •o • 0 • + Old Ungaran _ • 10; • P Oldest Ungaran r- + - • • • + • * + • • o • 0 • + o r\ U ' IIJII 111111111 IIIII 48 50 52 54 56 58 60 62 Si02 (wt.%) Fig. 4-29. Plot of Th against SiC»2 for rocks from Ungaran volcano.The correlation coefficient (0.444) is significant at the 95% confidence level (Table 4-20). 40 30- • o o • E • Yoimg Ungaran a°.- 20-3 • • + • O Parasitic Cones _- • + 4JP+"o" o o + Old Ungaran a a a. _ o • Oldest Ungaran 10 - 0 | II n in II | II in n n | n n in n | n n ni n | n in n II 11' " i " '• |" " '•' " 48 50 52 51 56 58 60 62 Si02 (wt.%) Fig. 4-30. Plot of Pb against SiC»2 for rocks from Ungaran volcano. Overall they have no significant correlation (Table 4-20). 250 210; 190; • O |" 170-i # a + • • " o -c • • Young Ungaran a 150-3 I. o O Parasitic Cones + Old Ungaran SI l++ 130; +-, • Oldest Ungaran 110-i °o 90 i n i u II I u n i n m n i" 'i II | n n | n II i n II | u u i II •! | II i' i IMI 4850 52 5456586062 Si02(wt%) Fig. 4-31. Plot of Zr against Si02 for rocks from Ungaran volcano. The correlation coefficient (0.484) is significant at the 95% confidence level (Table 4-20). 210 190 170 H + Andesite • Basaltic andesite I 150-1 ~ Basalt n° _f* S! 130- 110- 90 i 20 40 60 100 120 Rb (ppm) Fig. 4-32. Plot of Zr against Rb for rocks from Ungaran volcano. The correlation coefficient (0.434) is significant at the 95% confidence level (Table 4-20). 251 210 • Young Ungaran O Parasitic Cones + Old Ungaran • Oldest Ungaran Fig. 4-33. Plot of Zr against Hf for rocks from Ungaran volcano. The correlation coefficient is significant at the 95% confidence level. 60 50- E • Young Ungaran Cu 40 - Q. O Parasitic Cones + o + Old Ungaran D Oldest Ungaran 30 - • •- v. + • K> • 20 11111111111111 II II 111 n 111111 u 111 M u 111111 II 11111111 n II | 111111111 48 50 52 54 56 58 60 62 Si02 (wt.%) Fig. 4-34. Plot of Y against Si02 for rocks from Ungaran volcano. Overall they have no significant correlation (Table 4-20). 252 20 15 - + + E • Young Ungaran o. • D -I D 0« •• O Parasitic Cones o. O • + * • • O + Old Ungaran __ 10 - • Of o a O D Oldest Ungaran Z + aO OO II II I II II | II II I IT II | II II I II II) II II I M II | M tl I II II | II II I II II | II II I II 4850525456586062 S102 (wt.%) Fig. 4-35. Plot of Nb against S1O2 for rocks from Ungaran volcano. The correlation coefficient (0.288) is significant at the 95% confidence level (Table 4-20). Young Ungaran E a O Parasitic Cones e_ D. + Old Ungaran _S • Oldest Ungaran 1000 1000 X Ta (ppm) Fig. 4-36. Binary diagram of Nb versus Ta for rocks from Ungaran showing regression line. The correlation coefficient is significant at the 95% confidence level. 253 a » —a in c • u1—1 o •—•o» - a-* 03 O bo o <_> H_=: d § o o > § I-I CCJ L# -fl C _-> u S > o ——' o to >a c O •<_u o ic l-H c l-l o C+oH o .-a t# m Ha— Ov C/3 CO c _-a—s• .—Ca3 bfl 3 e. a-» « <4_l o <4-l :—• —•a I a_o> c jD .—Ma oo C/3 S • _a C^ 4 oo hfl d Ua (%T-a)__ 254 • Young Ungaran E «> Parasitic Cones _ + Old Ungaran e- p Oldest Ungaran 56 Si02(wt.%) Fig. 4-38. Plot of V against Si02 for rocks from Ungaran volcano showing regression line. The correlation coefficient is significant at the 95% confidence level. • Young Ungaran E o Parasitic Cones c o. + Old Ungaran • Oldest Ungaran 1 i ' r 50 54 56 Si02 (wt.%) Fig. 4-39. Plot of Sc against Si02 for rocks from Ungaran volcano showing regression line. The correlation coefficient is significant at the 95% confidence level. 255 a Young Ungaran 0 Parasitic Cones + Old Ungaran • Oldest Ungaran Si02(wt.%) Fig. 4-40. Plot of Co against Si02 for rocks from Ungaran volcano showing regression line. The correlation coefficient is significant at the 95% confidence level. B Young Ungaran E $ Parasitic Cones a. •w + Old Ungaran la • Oldest Ungaran u 1 i r | 48 50 52 54 56 58 60 62 Si02(wt.%) Fig. 4-41. Plot of Cr against Si02 for rocks from Ungaran showing regression line. The correlation coefficient is significant at the 95% confidence level. 256 0.70560 error limit H < 53% Si02 0.70540 " • > 53% Si02 _. / § 0.70520- / B Q • I /f 0.70500 " a ' / • > / _° ' / / i i i 0.70480 • / \ / >.- 0.70460 -I 1 r- • i i i i i | II i i i i i 45 50 55 60 65 Si02 (wt %) 0.7056 error limit n < 53% Si02 0.7054 ; . • > 53% Si02 _ g 0.7052 _. CO _ 0.7050 " 0.7048 0.7046 -1— 1 i 17 18 19 20 21 A1203(wt.%) Fig. 4-42. Plot of 87Sr/86Sr versus major element contents for samples from Ungaran. Error limit of 0.00005 (two standard deviation) is also plotted. 257 U. /U5b - & error limit ~ < 53% Si02 0.7054 - • > 53% Si02 / • \ < \ VO 0.7052 - oo _a--" ~N N i_ • V \ ° QN rv\- ' \ * 00 0.7050 - '•• * * v a. ' - • 0.7048 - ^a. • 1 / ^ -•" •X • / (\ IHAfi - U./U4D I • 1 • 1 ' | » 1 1 6 7 8 9 10 1 FeO (wt.%) 0.7056 3 error limit Q < 53% Si02 0.7054 - • > 53% Si02 a \ & 0.7052 - iji vo 00 .-' *\\ u 05 B s & 0.7050 na a i 0.7048 - \ • 0.7046 —, 1 J- T 2 3 4 6 MgO (wt.%) Fig. 4-42 (continued). Plot of 87Sr/86Sr versus major element contents for samples from Ungaran. Error limit of 0.00005 (two standard deviation) is also plotted 258 0.7056 B < 53% Si02 error limit 0.7054 1 • > 53% Si02 u H 0.7052 "i- r- 0.7050 " • a • 0.7048 • 0.7046 -J- 2.0 2.5 3.0 3.5 4.0 Na20 (wt.%) 0.7056 error limit B < 53% Si02 0.7054 - • > 53% Si02 u _ _. - a / § 0.7052 ~ D ~£_ t/a i t_ y i ' 0.7050 - D % B \ U *_ *_.N\ x ; 0.7048 ~ - .. 0 m" _ / ,'• 0.7046 f— -r— —i « 1 • 1— 1.0 1.5 2.0 2.5 3.0 3.5 4.0 K20 (wt.%) Fig. 4-42 (continued). Plot of 87Sr/86Sr versus major element contents for samples from Ungaran. Error limit of 0.00005 (two standard deviation) is also plotted. 259 0.7056 error limit B <53%Si02 J 0.7054 • > 53% Si02 H\ h 0.7052 ~ B \ VO 00 £ 0.7050 i ,' • 00 EH? i t • \ i \ 0.7048 " V • X — - • ' 0.7046 -r 1 —r— 6 8 10 12 CaO (wt.%) 0.7056 error limit Q <53%Si02 0.7054 • >53%Si02 u i a i § 0.7052 i V. H \ ^ \ W_ N v • - N r- 00 0.7050 - I \ t • • • * El I \ V > / \ • 0.7048 ~ \ \ _ 0.7046 —1— ~i— —r- 0.4 0.6 0.8 1.0 1.2 1.4 Ti02 (wt.%) Fig. 4-42 (continued). Plot of 87Sr/86Sr versus major element contents for samples from Ungaran. Error limit of 0.00005 (two standard deviation) is also plotted. 260 0.7056 B < 53% Si02 b error limit • > 53% Si02 0.7054 " £ 0.7052 vo 00 u • • _\ 0.7050 i El • 0.7048 " B _ 0.7046 "T 0.000 0.100 0.200 0.300 Rb/Sr 0.7056 - error limit • < 53% Si02 0.7054 - _ • > 53% Si02 El _. 0.7052 - • VIVO 00 • u VI 0.7050 " • • • r- «• El 00 • El 0.7048 ~ • El • • 0.7046 ~ ' 1 ' • 1 —r 300 400 500 600 700 Sr (ppm) Fig. 4-43. Plot of 87Sr/86sr versus trace element contents for samples from Ungaran. Error limit of 0.00005 (two standard deviation) is also plotted. 261 o ps in bn <^ C O O o O a • 1—1 --H e' CO CO II m cn en E m »n o p £?„ co V A r-» • • _:° I in CD O o 2 © CN r-~ O ii II c oty. i—i o bfl 'X_ •c _a »n c n Cai T cd •> ed o fa K bfl •a o c -j l-i & ^r o r- o >n o bo || r- P-i cn cn CA 262 o l-l in ^D <-l—o1 O cd r- *-*cd d Q c/i M o O o oI-. o 4—t o CU r- "o c X: 13 d bfl 13 [ u c o o -a X 13 oin (U o u in •a ~C/3 o c 3 r- cd ^o C/5 h-a £ d cd > o cd u |—ii c o co E o 00 o »n CaO ^C, o CuO --, J-> r- t» o in d 00 r- aV- ^_, C+OH "S _ VS o t• i—-I c .*—2 oin cd ^ 13 ^1- i_ 1^* 13 o CaO VD Eo JJ r~- 00 C Ca-,s_a 13 VH co d CO ^a r-» co. I 8t-H oc+-o a l-l • rH o 4_* o o E • —a C o cd o o Sbfil J-« a—» CoO t3 d -_a Ca in. "5t 1 '•S3 XT o . £cd *r, -So3 m t-H o I I I I 1 I 1 II I I I I I II I I I I I o ON O (Ti O r- Aauanb^jjj 263 Fig. 5-1. CIPW normative mineralogy for lavas from Ungaran. All data are plotted on the basis of analysed Fe203/FeO+Fe2C>3. • High-K calcalkaline P Shoshonite 12 Fe203/FeO 10- [] Shoshonite || High-K calcalkaline % 6H t_ 4- 2- I ri ,i,i, ,n, _< -J- OO CN vo (T, rroo«svo Fig. 5-2. Histogram of FeoOg/FeO ratio for rocks from Ungaran. 264 CaO Na20 K20 Fig. 5-3. AFM and Na20-CaO-K20 diagram for rocks from Ungaran volcano. Dashed and solid lines indicate fields for high-K calcalkaline and shoshonitic rocks respectively. 265 20 K20+Na20 ~] Shoshonite [I] High-K calcalkaline 10 I 3.75 4.25 4.75 5.25 5.75 6.25 6.75 Middle of interval (wt %) Fig. 5-4. Histogram of the total alkali content of lavas from Ungaran volcano. 1.4 1.2- L( • • B O H B . • 0.4 4- - ~T ' r —l 1— 48 50 52 54 56 58 60 62 Si02 (wt %) Fig. 5-5. Plot of K20/Na20 versus Si02 for rocks from Ungaran. 266 • • Q Q_ B 0 _. • * QB_ •> • • • • • • B _ Q 2- aB __ • Shoshonite • High-K calcalkaline -T- "T" -r~ 48 50 52 54 56 58 60 62 Si02 (wt %) Fig. 5-6. Plot of K20 versus Si02 for rocks from Ungaran. 20 Ti02 (~| Shoshonite p| High-K calcalkaline : -;;;;; Z:- .;.-.-- •-- 8 1(1- mmm _ •'mmm v I .:v;::v.; -Zx-:'x- ZZZZ :-:-:-:-:-:•:•:- > Z^ZZ: : Z'Z Z ••::::x:::x: : -:->.:.:v-.- ": :• 0.55 0.65 0.75 0.85 0.95 1.05 Middle of interval (wt %) Fig. 5-7. Histogram of Ti02 contents of rocks from Ungaran. 267 o CN u •-aS CN *-* -oa O "o3 cs 'toi !-, Q •s, J- 00 as u • 00 -J- (T\ • —H C .—-. cd £ fa La bJQ C 's t P a CD 6 a— a CO •St 1 r~ >n —H fci) T- -r~ g vo £3 c»o CN ^uonbajj 268 -Ja C o E in .-o, o O 1-1 1-1 o ta o • i-H E txQ cd s on ;_ on li o > D E •j_ Cj-l O O C_K i >n * —-< UH 269 10" Andesite -O- 919 -*- 924 « 10 2 _ T3 a % § t oo 10' 1 i i r T i 1 1 1 1 r -i 1 1 i i r la Ce Sm Hi Gd Yb Lu 10" Basaltic andesite -a- 922 -*- 821 10 2 _ ~ •a c o -3 5 101 l - 10 T i 1 r T I I I J i 1—i 1—i 1 r La Ce Sm Bi OJ Yb lu 10' Basalt •O- 832 -*• 326 a 10 : - a o JS a. S 01 03 1.0V 1 I 1 I I I 1 1 I I r T—i i—r La Ce Sm Bi G_ Yb Lu Fig. 6-1. Range of REE patterns for basalt (12 samples), basaltic andesite (8 samples) and andesite (9 samples) from Ungaran. Only the lower and upper level of the REE 270 VO (N e (N m m oo w ed E OQ cd E 3 > 6 •a o •c CU Pa E cd MD c« o CO 73 o c*-. -a-v !/) OO 6eu ^j y ^—» —PP.a a—. cd Pa a. w CJ a in --3 o fccO 1 in i i i "i jut i i i i—r a-* Cd CO eN CN i Pa O o o >. bi -=> o c a^puoip/aiduiBs o _s 00 271 -a 3 E -J gp .-> a E '>• in CO in E O Pa ___+ + $• Br*T{ 3 •3 .a 'tu _ a U E V £ 2 CO is O Q. u E 'CJ < \-2 |i •• 111 • llllll I I I linn I I I I c*i cs nillll i JTITT CO CS o o o o '© o o aa]Jpuoip/3]diuns ajupuoip/aidures 5 •_3 E -£ B +•*• E3 + + *• h3 3 Ua . a U a CO CO 01 JB "3 8P .3 11 U a. -1 o es o T ro o o I O ooo O o —a —a —a aU-ipuoip/ajdures ei__feu_ JCTBUIJJJ 272 •a E 00 M M E ccj 00 . C > a u c *— --1 E O •— O _ E o C J i- c •c o o o p -a •z. _• E B J .—i O 6P O O a * H in* v o* oo _ a E o O -3 cd -a _a E •c -I Pbaa Tc3d (EU 4—1 _ o o o o. B u 1) u E a-1 < _3 t> •5- o III i |ii i • n • i jn 111 i i i TTTT D llllll I r- || I I l l l CM — O m cs o O ooo o o o ajjjpuoijj/aidures 1 ajjjpuoip/aidures Pa -a 3 o -a E CJ o • in_a J-O! £Pa 00 CE ___. * * Q * o CJ O 3 O oo 3 O _ C 3 •Cl .—a cl> ("I on 0o0o E (Uo •" siPa s Pa Pa CL W O W CaO C_5 r-1 -+ "- ]J111 I —T" (•••ii • i—r- CN ^ s CN O O o o O o o o bO ._ sippuoq o/3\d IUBS .—a a>> ajjjpuoqD/ajdures UH X> 273 15.7 _3 m _Q n CaT a _x) (£» _, n oaW3_ ° DnJ-rtSa EP T§_ ft* _? Q_3 i«- Gl- s E0n_3 _-^=<_fr •H// N 15.5 • OD3 • MORB °° •s"; v 15.4 17.5 18.0 18.5 19.0 19.5 20.0 20.5 206Pb/204pb 40.5 40.0 a - a • _ 39.5 B fl,3B a, B- fCI ' a 0 o-a a D 3 S rP - O -0 - oa ^ 39.0 EQ _£ • o N 38.5 - Q p OIB 38.0 - « MORB _r* •*••.' 37.5 17.5 18.0 18.5 19.0 19.5 20.0 20.5 206pk/204pk Fig. 6-5. Plot of lead isotopic data for samples from MORB and OIB. Dashed line encloses samplesfrom MORB. Data from Gray (pers. comm., 1988). 274 15.8 /B \ / n \ I nn \ 15.7 / —3 a ^ 1 "^ a a \ 1 DDDD a_ ) n CP a • ana Q._a - J-5 •klD JM) I m ' * DU tDQEI l_ / \o / HO 3rwi man / 3 15.6 -Q d- • lci'cS-1 rf7 ida EiEr ,rj\ o El 15.5 a -£ • o o _ _\® a 0 OIB ai • Oceanic subduction a Continental subduction 15.4 I t t . i I...... 17.5 18.0 18.5 19.0 19.5 20.0 20.5 206pb/204Pb 40.5 40.0 a % -3 39.5 n I J -jF.' "TylrtS1 , B QE 3 3 i nr_ a_a " a, 39.0 oo o 38.5 a _ • OIB 38.0 • Oceanic subduction n Continental subduction 37.5 17.5 19.0 19.5 20.0 20.5 206Pb/204Pb Fig. 6-6. Plot of lead isotopic data for samples from OIB, oceanic crust and continental crust subduction. Dashed and solid lines enclose samples from oceanic and continental subduction respectively. Data from Gray (pers. cornzz 1988), 275 15.7 D - • ° _- ti a \ _, •• • £7 -a 15.6 ,JB\ B_0^] EP ^ _? ' «-& -3 OH 3 • _ Eg ^__L -2 • CL, ftp W^JL o 15.5 " El E. a EI OIB "•S?^/ • MORB o Oceanic subduction 15.4 i 1 ' 17.5 18.0 18.5 19.0 19.5 20.0 20.5 40.5 40.0" _ ED a -2 39.5 • • ,10 3 BBB_BBH EH 00,-9 • „a _3 39.0 00 o 38.5 • g • OIB 38.0 • MORB a Oceanic subduction 37.5 17.5 18.0 18.5 19.0 19.5 20.0 20.5 206Pb/204pb Fig. 6-7. Plot-of lead isotopic data for samples from oceanic crust subduction, MORB and OIB. Dashed and solid lines enclose samples from oceanic subduction and MORB respectively. Data from Gray (pers. Comm., 1988). 276 15.8 - . + + + • + • 15.7 - X _3 _ • X -r •>p o o -j .a c_ 15.6 - D Tholeiitic r- o © X Normal CA CN + Anomalous CA o • Ungaran o Leucititic 15.5 - i i i i -T--I—T-T-l-T 1 -i—i—i i i—r" • III i i i i --T • i i i i i i i t— 18.6 18.7 18.8 18.9 19.0 206Pb/204Pb 39.6 39.4 - + _ 39.2 -3 Cu D t o X JN • a _- § 39.0 • Tholeiitic X Normal CA 38.8 + Anomalous CA • Ungaran o Leucititic 38.6 -i—i—i—i—i—i—r—f- l • ' • 18.6 18.7 18.8 18.9 19.0 206Pb/204Pb Fig. 6-8. Plot of lead isotopic data for samples from Java. Data from Whitford et al. (1981). 277 CD 1— s_ ^~ < 3 o o OoNo u CO oo T-H < to -_ 3 CD c G o U o cd 3 4—» o a CO --—1 03 cd • •—* " < -u-» o a O \->B bij •- 3^- < cd OO _C u C D CM bQ "O o a C H < Jo CD o s Z, £ •*—> H O X + • O 3 < T3 O cd *" c C CaO cd CD cd c/5 "" 'E o o &< <—c CD r>- o ON T"~" *~-4 _- ccf ^^ > CD cd 1 C3 o i—i qdPOWdLOZ 278 o T3 T3 C C CM cd cd < co /-"N & •<* u 00 < CaO O o o U =3 o 2 N**a • --H c . »_. • i-H Id Id w ^ cd LO T13 jo crj .—H X a— <_D a '—'c —\ o 'o s—\ o JD c o •»—* t) JS CJ) cd E Uo „ ^ cd a-N > cd omo i—i ON _a E S 1) LO a, C/5 fe) CO o a. < _Q cd T3 PL< mE C t-. cd NO B o j-a> Da cu 3 s Q x> E o Oa 0 o cd CN acd in a—< 3 cd C/J ii Q U , > , M y~\ l_ Pi oo CO 0 ON VO LO I-H oo So o 00 • rH feb U-i o O cd •—ii< a_i OH < o T3 T3 C cd ©s o sC I .—a VO c <_> 11111 . o _c•—d* 1111111111 1111111111 1111111111 1111111111 1111 •r-b»b ra < r- vo uo CO CN s o O o O r- r- r-» o o r- JS98/JS_8 279 ON < r- cd ON < 3 cd cU < ui/i CQ 3 o u ri CQ O cd ocd cd • —-i O ° J i-a oe OU 3 O c c CO CQ § < _1 z D £ .G X + • O C/5 •a O c -*! cdc d cd > cd NO E ON o co 73 <_> i—• a—i 3a 4> cd C/l cd -G o l-H . I—» 00 w_ E oo 00 o r- & ^ oo cd oo in „ ON 3 in Qc uw cd >-i U o •e vo cd o o .bb 8 ,° •i-H lllll CO HrMiiniiiiiiiii|iiiiinii|niiiin'|»»''"4"" i"""'" o £ CH .3 CN ON 00 co CN vo c IS rn 00 NO "% P< 00 CO O 3 co o l-H CO CN > l-H 00 NO 00 r— 00 C+H O CN G o r-H I O 0 »o 0 10 o NO rn VO 0 0>o >0o O r- t> t> o 0 0 0 d 3d JS98/JS_;8 o d 281 -O o >H o 'c _ cd CJ CU 1- >H CU 3 O O C 00 *i o cd T1 ^ CQ PQ CQ & % C_ 1 P^H o o SO 1 Q i i CeO r cQo z z o fl l-l t * * 3 g £ s (1 9 oo d -MOR B OH N 00 nd W -_, an , l_ 13 * o 00 bit) -s O G M- "^ ON l_ 3 ro c c • o r cd ^ GdWh i p H a o dat a o n _ 00 Robin s howin g c i cd 04 w fror r gram s t a -C cd cd H D 60 . derd i cd •rH f-O P3 00 OH -D DS D P-1 • nn • i In ••• . !•••• • • • llllll I i I linn I I I 6-13 . Fig . CO CN H O '""' CN fro m O O o o u CD apuBiu'j/aiduiBS 282 (a) £ 0.0000 0.0010 0.0020 0.0030 0.0040 Rb/K (b) 1.2 0.2 -i • _l_ -j—i—l—i—i ' -i L 0.000 0.001 0.002 0.003 0.004 0.005 Rb/K Fig. 6-14 (a) Plot of Rb/K versus Rb for basalt samples from Ungaran with a mixing curve, (b) Companion plot of Rb/K versus 1/K. 283 0.7070 (a) • 0.7066 0.7062 7 0.7058 __ '. 0.7054 ™ _ • 00 0.7050 - ^ %_____ a! I L"--JL ka 0.7046 CaO t~ 90 0.7042 — 0.7038 0.7034 0.7030 • i _i _ 1— • i i .1 . i. i i lii • 1 ii i 0.000 0.001 0.002 0.003 0.004 0.005 Rb/K 0.7070 (b) L. CaO vo oo CO r- 90 20 .01K/86Sr Fig. 6-15. (a) Plot of Rb/K versus 87Sr/86Sr ratio 87Sr/86Sr for basalt samples from Ungaran with a mixing curve, (b) Companion plot of K/^Sr versus ^Sr/^Sr ratio. 284 0.7070 (a) 0.7065 0.7060 u 00 NO 00 _ 00 r^ 00 0.7025 2.5 3.0 5.0 5.5 (La/Ce)N (b) oo NO go oo r- 00 6 7 8 9 10 11 12 13 14 15 (Ce)N/86Sr Fig. 6-16. (a) Plot of (La/Ce)N versus ^Sr/^Sr ratio for basalt samples from Ungaran showing 2 possible mixing curves, (b) Companion plot between (Ce)N/86Sr versus BVSr/^Sr ratio. A = mixing between sample 832 and 326. B = mixing between sample 832 and 917. 285 (a) La 00 NO 00 "C 00 r~ 90 0.7030 0.6 (b) L. 00 NO 00 "T- 00 90 Fig. 6-17. (a) Plot of (La)N/Sr versus ^Sr/^Sr ratio for basalt samples from Ungaran with a mixing curve, (b) Companion plot of Sr/^Sr versus ^Sr/^Sr ratio. 286 0.7070 (a) 0.7065 0.7060 P 0.7055 r _. CaO NO 0.7050 t" 00 ~u 00 0.7045 r- 90 0.7040 t 0.7035 t 0.7030 '• » • i • « • ' • • • * • • • i • • • i • • • i • • • i • • • i • • • i • • • i • • • i • i . i • • . i • • • i • • • 0 10 12 14 16 II 20 22 24 26 28 30 (CeTYb)N (b) 00 NO go L. OO r- 00 0.7030 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 (Yb)N/86Sr Fig. 6-18. (a) Plot of (Ce/Yb)N versus "Sr/^Sr ratio for basalt samples from Ungaran with a mixing curve. The mixing curve is nearly straight because (YbJj/GSr in both end member is approximately 1. (b) Companion plot of (Yb)N/86Sr versus ^Sr/^Sr ratio. 287 (a) -a CaO NO 00 oo 90 0 12 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Zr/Y 0.7070 : (b) 0.7065 - 0.7060 j- 0.7055 r • * u 0.7050 _ oo \ - _ ° H B 00 0.7045 7 -. CO 0.7040 r» 90 0.7035 0.7030 0.7025 1 l 1- ' » i 1 1 2.2 2.4 2.6 2.8 3.0 3.2 3.4 Y/86Sr Fig. 6-19. (a) Plot of Zr/Y versus 87Sr/86Sr ratio for basalt samples from Ungaran with a mixing curve, (b) Companion plot of Y/^Sr versus ^Sr/^Sr ratio. 288 0.7070 (a) 0.7065 0.7060 0.7055 ka 00 S§ 0.7050 u CO so 0.7045 0.7040 F- 0.7035 t 0.7030 t 11Hll1111 1111111•I.I••.. I.... I.... 1.... I.... t.... I....t....t....| ,. 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 • Zr^ST) 0.7070 (b) 0.7065 0.7060 0.7055 00 NO 0.7050 00 _ 00 0.7045 r~- 00 0.7040 0.7035 F- 0.7030 •' ' • • • • ' • iiilii i i l • • . • i . . • • • . . . 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Nb/86sr Fig. 6-20. (a) Plot of Zr/Nb versus ^Sr^Sr ratio for basalt samples from Ungaran with a mixing curve, (b) Companion plot of Nb/^Sr versus 87Sr/86Sr ratio. 289 IH kH . oo _o Ca-a ">^ ON O cd CU H O _ E *—r X Ca-toa. E 3 CO cd cd O co Q cd •a CO cU ^^-r* l_ , _ eu c r- _ ~a'in E o G ••3 Oo CU CaO a—\ oo •o NO O _; S cd o 3CO »o cd C£O ON > c kH o cd •o «o - G aed kH cd la-< O « ,a—o* • ~H CJ b0 cd G cu £.G "3 i_ VOO ^r CN o O cu NO a—* l OO cd CQO ON r—1 kH Q CO 00 E NO _ o OO o 00 Hacd, oo c CU cd G CU o > CU G cu c O CU OO co -3 CaO • iH o • i-H CD > CU o •_ S3 CL, T3 3 O o CO c CO a, .2 "8 "8 Deu cd CH cu _: co co o '*—* PQ ca oa bO cd ID S3 S3 cd o. g. • —-> o c3 •5 S3 "cd £ i»-i cu C3 _ o eu cEd Ecd •3 oCU c o E 'ba u •o5 Q Q cd 3 cd CD o w> eu i_ o c OH eu •3 c Q •3 3 cd O o c/_ kH £ O O '-£ CU 3 eu Da bO CU C cd Da cd u Mean Range GRAIN SIZE (4) PHENOCRYSTS Plagioclase 22.3 18.0 - 26.0 up to 4 mm, on Clinopyroxene 11.4 10.0 - 13.0 average 0.4 - 0.8 mm Fe-Ti oxide 5.6 4.0 - 8.0 Amphibole 0.3 0.0 - 1.0 Other 0.06 0.0 - 0.25 GROUNDMASS 60.44 55.0 - 65.0 0.02 - 0.1mm GROUNDMASS TEXTURE intergranular, orthophyric, pilotaxitic Other = pseudomorph after olivine. Table 3-1. Petrography of basalts from Oldest Ungaran. Modal analyses are in volume %. PHENOCRYSTS GROUNDMASS Mean (11) Range Mean (2) Range Si02 46.48 43.96 - 53.71 51.25 45.54 - 56.97 M203 33.20 28.89 - 35.95 30.08 25.50 - 34.66 FeO 1.05 0.45 - 2.98 1.28 0.74 - 1.81 MgO 0.36 0.04 - 2.47 0.18 0.07 - 0.29 CaO 16.78 11.23 - 19.04 12.36 7.72 - 17.00 Na20 1.72 0.30 - 4.65 3.19 1.85 - 4.53 K20 0.19 0.06 - 0.50 1.65 0.14 - 3.16 An 83.40 55.48 - 96.87 61.05 39.23 - 82.87 Ab 15.50 2.76 - 41.65 28.98 16.32 - 41.65 Or 1.18 0.37 - 2.94 9.97 0.81 - 19.12 Table 3-2. Chemical data for plagiocase in basalts from Oldest Ungaran. 293 PHENOCRYSTS GROUNDMASS Mean (7) Range Mean (1) SifJ2 50.27 48.90 - 57.50 48.28 Ti02 0.58 0.47 - 0.82 1.13 A1203 3.65 3.04 - 4.52 4.95 Cr203 0.06 n.d. - 0.12 n.d. FeO 8.51 7.78 - 8.93 9.13 MnO 0.25 0.16 - 0.31 0.27 MgO 14.10 13.36 - 14.72 13.85 CaO 22.10 21.98 - 22.29 21.96 Na20 0.44 0.13 - 1.26 0.37 Wo 48.11 46.92 - 50.52 49.38 En 42.68 39.77 - 44.20 43.28 Fs 9.22 5.77 - 12.78 7.34 Table 3-3. Chemical data for clinopryroxene in basalts from Oldest Ungaran. PHENOCRYSTS GROUNDMASS Mean (2) Range Mean (1) SiO_ 0.06 0.05 - 0.07 0.05 Ti02 10.78 10.06 - 10.91 18.92 Al203 5.67 5.62 - 5.73 1.25 Cr203 0.09 0.07 - 0.12 n.d. FeO 76.14 75.92 - 76.36 72.18 MnO 0.51 0.49 - 0.52 0.65 MgO 2.35 2.33 - 2.36 0.88 CaO n.d n.d 0.14 Fe203 42.42 42.06 - 42.77 29.29 FeO 37.98 37.88 - 38.07 45.82 USP* 33.69 33.25 - 34.14 56.35 Table 3-4. Chemical data for Fe-Ti oxide in basalts from Oldest Ungaran. USP* - molecular percent ulvospinel. PHENOCRYSTS Mean (4) Range Si02 38.93 37.75 - 39.95 Ti02 2.82 2.65 - 2.96 A1203 12.22 12.03 - 12.50 FeO 11.48 11.25 - 11.83 MnO 0.24 0.18 - 0.34 MgO 11.97 11.29 - 12.63 CaO 11.04 10.79 - 11.45 Na20 2.72 2.48 - 3.03 K20 | 1.25 1.22 - 1.29 Table 3-5. Chemical data for amphibole in basalts from Oldest Ungaran. PHENOCRYSTS Mean (3) Range Si02 37.17 36.80 - 37.50 A1203 0.56 n.d - 0.98 FeO 30.18 28.17 - 33.48 MnO 0.71 0.43 - 0.93 MgO 30.98 27.41 - 33.04 CaO 0.58 0.21 - 1.14 Fo 64.56 59.33 - 67.64 Fa 35.44 32.36 - 40.67 3-6. Chemical data for olivine in basalts from Oldest Ungaran. 295 Mean GRAIN SIZE (D PHENOCRYSTS Plagioclase 21.0 Feldspar to 3.2 mm, Clinopyroxene 6.0 but mostly 0.4 - 0.8 mm. Fe-Ti oxide 3.0 Other minerals rangefrom 0.2 to Amphibole 10.0 3.0 mm but mostly are between Mica 3.0 0.5 and 1.2 mm. GROUNDMASS 57.0 GROUNDMASS TEXTURE intergranular, orthophyric Table 3-7. Petrography of andesite from Oldest Ungaran. Modal analysis is in volume %. PHENOCRYSTS GROUNDMASS Mean (6) Range Mean (2) Range Si02 44.61 43.36 - 46.52 45.05 44.71 - 45.39 A1203 35.67 33.60 - 36.12 34.86 34.83 - 34.89 FeO 0.73 0.52 - 1.42 0.68 0.66 - 0.71 MgO 0.10 0.02 - 0.42 0.04 0.04 - 0.04 CaO 18.03 16.17 - 19.12 17.78 17.49 - 18.08 1.44 - 1.48 Na20 1.35 0.85 - 2.09 1.46 0.10 - 0.11 K20 0.10 0.04 - 0.20 0.10 An 87.50 80.53 - 92.24 86.70 86.16 - 87.24 Ab 11.90 7.42 - 18.43 12.72 12.24 - 13.19 Or 0.60 0.23 - 1.19 0.59 0.52 - 0.65 Table 3-8. Chemical data for plagioclase in andesite from Oldest Ungaran. 296 PHENOCRYSTS GROUNDMASS Mean (3) Range Mean (1) 49.37 Si02 49.49 49.05 - 49.71 TiC^ 0.75 0.71 - 0.83 0.88 4.13 A1203 3.89 3.56 - 4.60 FeO 8.12 7.93 - 8.33 8.29 MnO 0.26 0.23 - 0.28 0.26 MgO 14.79 14.36- 15.18 14.59 CaO 22.14 21.93 - 22.42 22.08 Na20 0.42 0.33 - 0.51 0.36 Wo 48.77 47.85 - 49.38 48.67 En 45.75 44.84 - 45.93 44.72 Fs 6.07 5.79 - 6.22 6.62 Table 3-9. Chemical data for clinopyroxene in andesite from Oldest Ungaran. PHENOCRYSTS GROUNDMASS Mean (2) Range Mean (1) Si02 0.05 n.d - 0.10 0.09 Ti02 11.29 11.20 - 11.37 10.41 A1203 4.42 4.25 - 4.58 3.60 Cr203 0.07 0.06 - 0.08 0.06 FeO 76.61 76.43 - 76.78 78.65 MnO 0.56 0.52 - 0.60 0.50 MgO 2.23 2.10 - 2.35 2.20 CaO 0.04 n.d - 0.07 0.10 Na20 0.15 0.11 - 0.19 n.d Fe203 42.70 42.56 - 42.83 45.71 FeO 38.19 38.14 - 38.24 37.52 USP* 34.57 34.33 - 34.81 31.28 Table 3-10. Chemical data for Fe-Ti oxide in andesite from Oldest Ungaran. USP* = molecular percent ulvospinel. PHENOCRYSTS Mean (2) Range Si02 41.29 40.46 - 42.11 TiO_ 2.06 1.90 - 2.22 A1203 10.66 10.52 - 10.75 FeO 14.73 14.45 - 15.00 MnO 0.54 0.52 - 0.56 CaO 11.97 11.32 - 12.56 Na20 1.89 1.79 - 1.99 K20 1.14 1.03 - 1.25 Table 3-11. Chemical data for amphibole in andesite from Oldest Ungaran. PHENOCRYSTS Mean (2) Range Si02 37.56 36.58 - 38.53 Ti02 4.58 4.43 - 4.72 A1203 16.42 16.33- 16.52 FeO 13.05 12.76- 13.33 Mn 0.14 0.13- 0.14 MgO 15.84 15.39- 16.28 CaO 0.04 0.02- 0.05 Na20 0.80 0.78- 0.81 K20 8.49 8.40- 8.57 Table 3-12. Chemical data for mica in andesite from Oldest Ungaran. 298 Mean Range GRAIN SIZE (6) PHENOCRYSTS Plagioclase 23.4 17.5 - 28.0 up to 1.6mm, on Clinopyroxene 9.4 5.0 - 13.5 average 0.4 mm Fe-Ti oxide 5.0 2.5 - 7.0 Amphibole 0.6 0.0 - 3.5 Olivine 1.1 0.5 - 2.5 GROUNDMASS 60.8 58.0 - 63.0 up to 0.2 mm GROUNDMASS TEXTURE orthophyric pilotaxitic, intergranular Table 3-13. Petrography of basalts from Old Ungaran. Modal analyses are in volume %. PHENOCRYSTS GROUNDMASS Mean (19) Range^ Mean (6) Range Si02 48.46 44.44 - 52.25 50.92 45.94 - 57.66 A1203 32.63 29.92 - 35.61 30.90 25.77 - 34.40 FeO 0.63 0.48 - 0.86 0.74 0.52 - 1.13 MgO 0.07 0.03 - 0.10 0.06 0.02 - 0.09 CaO 15.41 12.47 - 18.77 13.13 7.36 - 16.68 Na20 2.56 0.55 - 4.31 3.51 1.36 - 4.94 K20 0.24 0.05 - 0.45 0.76 0.16 - 3.15 An 75.86 60.11 - 94.58 64.30 37.04 - 81.70 Ab 22.76 5.05 - 37.60 31.20 17.37 - 44.08 Or 1.38 0.29 - 2.65 4.50 0.93 - 18.88 Table 3-14. Chemical data for plagioclase in basalts from Old Ungaran. 299 PHENOCRYSTS GROUNDMASS ! Mean (17) Range Mean (1) SiO_ 51.33 49.97 - 53.23 50.51 Tif^ 0.45 0.10 - 0.78 0.69 AI2O3 3.36 1.35 - 4.94 3.45 Cr203 0.08 n.d. - 0.11 n.d FeO 8.53 7.53 - 9.91 7.96 MnO 0.42 0.23 - 0.99 0.29 MgO 13.92 13.45 - 14.64 14.59 CaO 21.57 20.86 - 22.77 22.68 Na20 0.33 0.13 - 1.02 0.46 Wo 46.11 43.95 - 48.34 48.08 En 41.46 40.41 - 43.04 43.90 Fs 12.43 8.87 - 15.18 8.02 Table 3-15. Chemical data for clinopyroxene in basalts from Old Ungaran. PHENOCRYSTS GROUNDMASS Mean (4) Range Mean (2) Range Si02 0.02 n.d - 0.06 0.04 n.d - 0.08 Tifh 12.19 9.82 - 14.77 12.57 10.98 - 14.16 Al203 3.87 1.85 - 5.21 3.22 2.10 - 4.34 Cr203 0.05 n.d. - 0.08 0.03 n.d - 0.07 FeO 76.60 74.84 - 77.52 77.44 77.36 - 77.53 MnO 0.71 0.62 - 0.83 0.66 0.60 - 0.71 MgO 1.98 0.81 - 3.06 1.62 1.28 - 1.96 CaO n.d n.d 0.09 0.07 - 0.12 Na20 2.56 0.55 - 4.31 3.51 1.36 - 4.94 Fe203 41.56 36.83 - 45.42 41.58 39.46 - 43.71 FeO 39.17 35.72 - 42.05 40.02 38.20 - 41.85 USP* 36.90 30.18 - 44.19 37.60 33.43 - 41.77 Table 3-16. Chemical data for Fe-Ti oxide in basalts from Old Ungaran. USP* = molecular percent ulvospinel. 300 PHENOCRYSTS Mean (2) Minimum Maximum 40.86 41.88 Si02 41.37 3.19 Ti02 3.15 3.10 12.44 12.58 A1203 12.51 FeO 12.23 12.13 12.32 MnO 0.25 0.22 0.28 MgO 13.28 13.10 13.45 CaO 11.75 11.65 11.84 2.10 Na20 2.06 2.02 1.24 K20 1.23 1.22 Table 3-17. Chemical data for amphibole in basalts from Old Ungaran. PHENOCRYSTS Mean (8) Minimum Maximum Si02 37.73 31.73 38.04 A1203 0.20 0.12 0.31 FeO 28.34 26.19 32.55 MnO 0.66 0.53 0.95 MgO 33.03 29.27 34.84 CaO 0.16 n.d 0.30 Fo 67.47 61.57 70.33 Fa 32.53 29.67 38.43 Table 3-18. Chemical data for olivine in basalts from Old Ungaran. 301 Mean Range GRAIN SIZE (5) PHENOCRYSTS Plagioclase 21.4 19.0 - 24.0 range from 0.2 to Clinopyroxene 10.0 7.0 - 14.0 2.0 mm, but mostly Fe-Ti oxide 6.2 5.0 - 8.0 are between 0.4 and Amphibole 0.2 0.0 - 1.0 0.6 mm Olivine 0.6 0.50 - 1.0 GROUNDMASS 61.5 57.5 - 64.3 0.01 - 0.2 mm GROUNDMASS TEXTURE pilotaxitic, intergranular and interstitial Table 3-19. Petrography of basaltic andesites from Old Ungaran. Modal analyses are in volume %. PHENOCRYSTS GROUNDMASS Mean (6) Range Mean (3) Range Si02 49.34 46.95 - 51.58 49.91 45.19 - 52.34 Al203 32.04 30.43 - 33.69 31.55 29.96 - 34.72 FeO 0.66 0.61 - 0.72 0.72 0.64 - 0.84 MgO 0.05 0.04 - 0.10 0.05 0.03 - 0.06 CaO 14.53 12.67 - 16.57 14.19 12.24 - 18.04 Na20 3.10 2.00 - 4.20 3.25 1.31 - 4.27 K20 0.26 0.14 - 0.41 0.33 0.07 - 0.47 An 71.06 61.04 - 81.40 69.30 59.70 - 88.03 Ab 27.40 17.78 - 36.61 28.80 11.57 - 37.69 Or 1.54 0.82 - 2.35 1.92 0.41 2.74 Table 3-20. Chemical data for plagioclase in basaltic andesites from Old Ungaran. 302 PHENOCRYSTS GROUNDMASS Mean (9) Range Mean (1) 47.31 - 52.00 51.09 Si02 49.80 0.33 Ti02 0.60 0.38 - 0.83 2.24 - 6.76 2.31 A1203 3.98 n.d. - 0.21 0.04 Cr203 0.03 FeO 8.06 6.51 - 8.98 9.12 MnO 0.36 0.15 - 0.58 0.58 MgO 14.38 13.28 - 15.45 14.70 CaO 22.44 21.18 - 23.86 21.50 0.24 - 0.40 0.33 Na20 0.32 Wo 49.06 45.44 - 54.56 45.87 En 43.85 41.80 - 45.02 43.62 Fs 7.28 2.82 - 10.13 10.52 Table 3-21. Chemical data for clinopyroxene in basaltic andesitesfrom Ol d Ungaran. PHENOCRYSTS GROUNDMASS Mean (2) Range Mean (2) Range Si02 0.08 0.06 - 0.10 0.06 0.05 - 0.08 Ti02 7.68 7.63 - 7.73 12.45 10.75 - 14.16 AI2O3 4.64 4.63 - 4.66 2.31 2.10 - 2.52 Cr203 0.07 0.05 - 0.09 0.04 n.d - 0.07 FeO 79.50 79.45 - 79.54 78.60 77.36 - 79.84 MnO 0.73 0.72 - 0.73 0.66 0.65 - 0.69 MgO 2.05 2.04 - 2.05 1.24 1.19 - 1.29 CaO 0.04 n.d - 0.09 0.10 0.07 - 0.14 Fe203 49.36 49.27 - 49.45 42.54 39.39 - 45.69 FeO 35.08 34.96 - 35.20 40.32 38.73 - 41.91 USP* 23.72 23.57 - 23.87 36.90 31.99 41.81 Table 3-22. Chemical data for Fe-Ti oxide in basaltic andesites from Old Ungaran. USP* = molecular percent ulvospinel. 303 PHENOCRYSTS Mean (2) Range Si02 38.98 38.77 - 39.20 Ti0_ 2.24 2.06 - 2.42 A1203 14.48 14.18 - 14.78 Cr203 0.02 n.d - 0.04 FeO 11.34 10.67 - 12.01 Mn 0.11 0.08 - 0.13 MgO 13.84 13.42 - 13.86 CaO 12.68 12.64 - 12.73 Na20 2.13 2.03 - 2.17 K20 1.46 1.34 - 1.57 Table 3-23. Chemical data for amphibole in basaltic andesites from Old Ungaran. PHENOCRYSTS Mean (3) Range Si02 37.03 36.86 - 37.26 A1203 0.06 n.d - 0.12 FeO 29.30 28.53 - 30.47 MnO 0.78 0.70 - 0.83 MgO 32.57 31.47 - 33.26 CaO 0.19 0.13 - 0.32 Fo 66.45 64.79 - 67.51 Fa 33.55 32.49 - 35.21 Table 3-24. Chemical data for olivine in basaltic andesites from Old Ungaran. 304 Mean GRAIN SIZE (D PHENOCRYSTS Plagioclase 25.0 up to 2.0 mm in diameter, Clinopyroxene 4.0 but mostly between 0.4 and 0.8 mm. Fe-Ti oxide 6.0 Amphibole 5.0 GROUNDMASS 60.0 0.02 - 0.2 mm GROUNDMASS TEXTURE intergranular and pilotaxitic Table 3-25. Petrography of andesite from Old Ungaran. Modal analysis is in volume %. PHENOCRYSTS GROUNDMASS Mean (3) Range Mean (1) Si02 51.91 50.60 - 53.09 53.82 A1203 30.38 26.69 - 31.25 29.02 FeO 0.48 0.38 - 0.53 0.47 MgO 0.05 0.03 - 0.06 0.02 CaO 12.18 11.41 - 13.10 10.86 Na20 4.65 4.18 - 5.03 5.32 K20 0.36 0.31 - 0.40 0.49 An 57.96 54.46 - 62.28 51.54 Ab 40.00 35.96 - 43.44 45.69 Qr 2.04 1.75 - 2.26 2.77 Table 3-26. Chemical data for plagioclase in andesite from Old Ungaran. 305 PHENOCRYSTS GROUNDMASS Mean (5) Range Mean (1) Si02 51.20 50.41 - 51.72 51.09 Ti0_ 0.34 0.31 - 0.42 0.34 A1203 2.05 1.66 - 2.68 1.99 Cr203 n.d n.d - n.d FeO 8.90 8.39 - 9.46 9.14 MnO 0.64 0.62 - 0.70 0.67 MgO 15.25 14.71 - 15.80 14.98 CaO 21.09 20.85 - 21.27 21.32 Na20 0.44 0.37 - 0.64 0.43 Wo 44.60 43.22 - 45.57 45.03 En 44.98 43.95 - 45.53 43.97 Fs 10.42 9.25 - 11.25 11.00 Table 3-27. Chemical data for clinopyroxene in andesites from Old Ungaran. PHENOCRYSTS GROUNDMASS Mean (1) Mean(l) Si02 0.04 0.06 Ti02 7.58 8.82 A1203 2.88 2.80 Cr203 n.d 0.05 FeO 80.78 81.29 MnO 0.85 0.78 MgO 2.43 1.24 CaO 0.16 0.02 Fe203 52.24 49.11 FeO 33.77 37.10 USP* 22.48 26.41 Table 3-28. Chemical data for Fe-Ti oxide in andesites from Old Ungaran. USP* = molecular percent ulvospinel. 306 PHENOCRYSTS Mean (2) Range 41.66 Si02 41.62 41.57 - Ti02 2.78 2.76 - 2.80 11.82 A1203 11.70 11.58 - 0.04 Cr203 0.04 0.04 - FeO 12.51 12.49 - 12.53 MnO 0.40 0.37 - 0.42 MgO 14.26 14.23 - 14.30 CaO 11.67 11.63- 11.71 Na20 2.44 2.40 - 2.48 K20 1.15 1.14 - 1.17 Table 3-29. Chemical data for amphibole in andesites from Old Ungaran. Mean GRAIN SIZE (D PHENOCRYSTS Plagioclase 25.5 Feldspar to 2.0 mm Clinopyroxene 8.0 mostly 0.4 - 0.6 mm, Fe-Ti oxide 8.0 other minerals less than 0.8 mm. aAmphibole 1.0 GROUNDMASS 57.5 up to 0.2 mm GROUNDMASS TEXTURE orthophyric and pilotaxitic Table 3-30. Petrography of basalt from Parasitic Cones. Modal analysis is in volume %. 307 PHENOCRYSTS GROUNDMASS Mean (5) Range Mean (1) Si0_ 50.45 47.76 - 54.91 49.36 A1203 31.42 28.75 - 33.20 32.11 FeO 0.62 0.50 - 0.79 0.66 MgO 0.06 0.04 - 0.09 0.03 CaO 13.71 10.23 - 15.80 13.32 Na20 3.51 2.53 - 5.08 3.24 K20 0.23 0.14 - 0.45 0.27 An 67.40 51.26 - 76.90 69.84 Ab 31.30 22.28 - 46.06 28.59 Or 1.30 0.81 - 2.68 1.57 Table 3-31. Chemical data for plagioclase in basalt from Parasitic Cones. PHENOCRYSTS GROUNDMASS Mean (6) Range Mean (1) Si0_ 47.56 44.48 - 52.44 50.97 Ti0_ 0.97 0.21 - 1.51 0.48 AI2Q3 7.05 2.33 - 9.74 2.59 Cr203 0.07 0.04- 0.11 0.04 FeO 7.97 7.21 - 8.71 9.35 MnO 0.18 0.10 - 0.43 0.42 MgO 12.94 11.44 - 14.34 15.29 CaO 23.03 21.39 - 23.64 20.45 Na20 0.23 0.13 - 0.34 0.39 Wo 52.25 44.17 - 56.20 43.98 En 40.67 36.83 - 43.22 45.77 Fs 7.08 2.97 - 14.62 10.23 Table 3-32. Chemical data for clinopyroxene in basalt from Parasitic Cones. 308 PHENOCRYSTS GROUNDMASS Mean (1) Mean (1) 0.47 Si02 0.06 Ti0_ 7.58 3.37 0.32 Al203 2.88 n.d Cr203 n.d FeO 80.91 87.44 MnO 0.85 0.26 MgO 2.43 0.25 CaO 0.02 0.48 Na20 0.05 0.26 Fe203 52.08 60.57 FeO 34.05 33.34 USP* 22.53 10.01 Table 3-33. Chemical data for Fe-Ti oxide in basalt from Parasitic Cones. USP* = molecular percent ulvospinel. PHENOCRYSTS Rim(l) Core(l) Si02 40.73 39.54 Ti02 2.62 2.86 A1203 12.54 12.08 ' Cr203 0.04 0.04 FeO 13.21 12.70 MnO 0.32 0.28 MgO 13.03 12.67 CaO 11.10 11.17 Na20 2.44 2.29 K20 1.21 1.16 Table 3-34. Chemical data for amphibole in basalt from Parasitic Cones. 309 PHENOCRYSTS Mean (4) Minimum Maximum Si02 36.87 36.05 38.07 A1203 0.22 n.d 0.30 FeO 31.33 26.24 35.86 MnO 0.85 0.80 1.04 MgO 30.35 26.61 34.76 CaO 0.42 0.31 0.69 Fo 63.21 86.94 70.24 Fa 36.78 29.76 43.06 Table 3-35. Chemical data for olivine in basalt from Parasitic Cones. Mean Range GRAIN SIZE (5) PHENOCRYSTS Plagioclase 26.5 23.0 - 31.5 feldspar up to 2.0 mm Clinopyroxene 7.3 4.0 - 10.0 but mostly 0.4 - Fe-Ti oxide 3.2 2.0 - 5.0 0.6 mm Amphibole 1.8 1.0 - 2.5 Other minerals up to Olivine 0.04 0.1 - 1.0 3.0 mm, but usually (or pseudomorph) 0.4 - 0.8 mm. GROUNDMASS 61.9 57.0 - 65.8 0.02 - 0.32 mm. GROUNDMASS TEXTURE intergranular, interstitial and pilotaxitd c Table 3-36. Petrography of basaltic andesites from Parasitic Cones. Modal analyses are in volume %. 310 PHENOCRYSTS GROUNDMASS Mean (70) Range Mean (10) Range Si02 51.64 43.76 - 64.67 54.69 47.31 - 57.36 A1203 30.29 10.89 - 35.66 27.99 18.79 - 33.55 FeO 0.70 0.23 - 1.62 0.64 0.32 - 1.60 MgO 0.09 0.02 - 0.51 0.07 0.03 - 0.27 CaO 17.76 5.42 - 19.30 13.23 8.38 - 16.66 Na20 3.60 0.77 - 13.04 4.00 2.14 - 6.33 K20 0.79 0.04 - 4.03 2.55 0.13 - 0.85 An 69.70 25.27 - 93.00 65.74 40.48 - 80.40 Ab 27.70 6.80 - 72.10 32.05 18.80 - 55.30 Or 4.70 0.23 - 23.90 2.23 .75 - 4.91 Table 3-37. Chemical data for feldspar in basaltic andesites from Parasitic Cones. PHENOCRYSTS GROUNDMASS Mean (6) Range Mean (3) Range Si02 51.12 48.8 - 52.2 50.66 49.18 - 51.63 TK^ 0.34 0.13 - 0.78 0.49 0.28 - 0.77 AI2O3 2.06 0.92 - 4.79 2.12 1.79 - 2.66 FeO 8.48 7.77 - 8.99 7.58 8.22 - 12.92 MnO 0.76 0.24 - 1.05 0.53 0.37 - 0.62 MgO 14.26 13.65 - 15.15 14.72 13.40 - 15.4 22.61 CaO 21.74 - 23.01 21.11 20.10 - 21.70 Na20 0.33 0.25 - 0.39 0.28 0.21 - 0.35 47.69 Wo 45.01 - 50.64 44.22 42.87 - 45.11 41.82 En 39.52 - 44.86 42.87 39.80 - 45.11 Fs 10.49 6.04 - 13.10 12.91 9.78 - 17.33 1 data for clinopyroxene in basaltic andesites from Parasitic Cones. 311 PHENOCRYSTS GROUNDMASS Mean (4) Range Mean (2) Range Si0_ 0.06 n.d - 0.10 0.14 n.d - 0.14 Ti02 10.63 8.35 - 12.19 13.30 10.15 - 16.46 A12CJ3 3.10 1.81 - 3.96 1.49 1.48 - 1.50 Cr203 0.09 n.d - 0.13 0.09 n.d - 0.05 FeO 79.38 77.69 - 81.12 78.97 76.90 - 80.85 MnO 0.61 0.58 - 0.60 0.62 0.57 - 0.60 MgO 1.43 0.99 - 1.74 1.10 0.83 - 1.37 CaO 0.06 n.d - 0.12 0.08 0.06 - 0.11 Fe203 45.30 41.96 - 49.81 41.79 35.83 - 47.75 FeO 38.60 36.35 - 39.93 41.27 37.88 - 44.66 USP* 31.90 25.10 - 36.73 38.85 29.82 - 47.87 Table 3-39. Chemical data for Fe-Ti oxide in basaltic andesitesfrom Parasiti c Cones. USP* = molecular percent ulvospinel. PHENOCRYSTS Rim (1) Core (1) Mean (2) 39.94 Si02 39.70 40.18 1.70 Ti02 1.73 1.67 14.00 Al203 14.02 13.98 FeO 13.36 13.39 13.38 MnO 0.31 0.26 0.29 MgO 12.85 13.36 13.10 CaO 11.90 11.95 11.93 2.31 Na20 2.25 2.37 1.03 K20 1.02 1.03 Table 3-40. Chemical data for amphibole in basaltic andesitesfrom Parasiti c Cones. 312 XENOCRYSTS Mean (3) Minimum Maximum 41.66 SiO_ 44.51 41.33 0.11 0.11 A1203 0.11 FeO 10.55 10.34 10.88 MnO 0.18 0.10 0.17 MgO 47.17 46.82 47.39 CaO 0.07 0.07 0.07 Fo 88.80 88.58 89.07 Fa 11.20 11.42 11.93 Table 3-41. Chemical data for olivine xenocryst in basaltic andesites from Parasitic Cones. Mean Range GRAIN SIZE (5) PHENOCRYSTS Plagioclase 26.2 25.0 - 33.0 feldspar to 4.0 mm Clinopyroxene 7.1 5.0 - 9.5 but mostly 0.4 - Fe-Ti oxide 6.5 2.0 - 9.5 0.8 mm Amphibole 4.3 1.0 - 7.0 Other minerals 0.2 - Mca 0.02 0.0 - 1.0 0.5 mm.Fe-Ti oxide Other 1.00 0.25 - 1.0 usually less than 0.3 mm GROUNDMASS 57.40 55.0 - 60.0 0.02 - 0.32 mm GROUNDMASS TEXTURE Intergranular, orthophyric, intLTsertal< , and pilotaxitic Other = pseudomorphs after olivine. Table 3-42. Petrography of andesites from Parasitic Cones. Modal analyses are in volume %. 313 PHENOCRYSTS GROUNDMASS Mean (13) Range Mean (1) SiO_ 55.42 49.48 - 58.88 61.21 Al_03 28.08 25.83 - 32.03 23.70 FeO 0.44 0.25 - 0.69 0.66 MgO 0.06 0.02 - 0.10 0.09 CaO 9.97 7.46 - 14.72 6.56 Na20 5.41 2.77 - 6.43 5.57 K20 0.62 0.22 - 0.99 2.17 An 48.60 37.00 - 73.60 34.10 Ab 47.80 25.10 - 57.50 52.40 Or 3.60 1.31 - 5.80 13.40 Table 3-43. Chemical data for rims and cores of plagioclase phenocrysts in andesites from Parasitic Cones. Cores Rims Mean (5) Range Mean (6) Range Si02 55.86 54.40 - 58.55 54.84 49.48 - 58.88 A12Q3 27.83 25.83 - 28.97 28.44 25.99 - 32.03 FeO 0.37 0.28 - 0.59 0.49 0.25 - 0.69 MgO 0.06 0.02 - 0.09 0.06 0.02 - 0.10 CaO 9.69 7.52 - 10.84 10.43 7.46 - 14.72 Na20 5.56 4.90 - 6.43 5.15 2.77 - 6.34 K20 0.64 0.45 - 0.99 0.58 0.22 - 0.87 An 47.22 36.98 - 53.55 51.6 37.4 - 73.6 Ab 49.06 43.80 - 57.22 45.6 25.1 - 57.4 Or 3.72 2.65 - 5.80 3.41 1.31 - 5.22 Table 3-44. Chemical data for plagioclase rims and cores in andesites from Parasitic Cones. 314 PHENOCRYSTS Mean (6) Range Si02 49.92 47.80 - 51.60 TiC_ 0.52 0.12- 1.03 A1203 3.40 0.87 - 7.08 Cr203 0.05 0.03- 0.11 FeO 9.36 8.12- 10.80 MnO 0.59 0.13- 1.08 MgO 13.14 12.23 - 13.63 CaO 22.71 22.06- 22.39 Na20 0.31 0.16- 0.38 Wo 49.13 46.27 - 52.13 En 39.54 37.31 - 42.57 Fs 11.32 5.29- 16.42 Table 3-45. Chemical data for clinopyroxene in andesites from Parasitic Cones. PHENOCRYSTS GROUNDMASS Mean (1) Mean (1) Si02 0.05 0.10 Ti0_ 12.30 11.20 A1203 1.14 1.15 FeO 79.03 79.69 MnO 0.48 0.60 MgO 1.64 1.64 CaO 0.08 0.07 Fe203 44.06 46.00 FeO 39.38 38.29 USP* 35.81 32.73 Table 3-46. Chemical data for Fe-Ti oxide in andesites from Parasitic Cones. USP* = molecular percent ulvospinel. 315 PHENOCRYSTS Mean (6) Range Si02 39.49 39.71 - 41.07 TiO_ 2.89 2.64 - 3.09 A1203 14.40 13.55 - 14.91 Cr203 0.07 0.04 - 0.11 FeO 11.06 10.74 - 11.44 MnO 0.13 0.10 - 0.20 MgO 13.61 12.65 - 14.07 CaO 12.41 12.14 - 12.70 Na20 2.31 1.91 - 2.65 K20 1.27 1.21 - 1.31 Table 3-47. Chemical data for amphibole in andesites from Parasitic Cones. PHENOCRYSTS Mean (1) Si02 37.34 Ti02 4.88 Al203 15.13 FeO 17.42 Mn 0.34 MgO 14.60 CaO 0.02 Na20 0.62 K20 9.64 Table 3-48. Chemical data for mica in andesites from Parasitic Cones. 316 Mean Range GRAIN SIZE (7) PHENOCRYSTS Plagioclase 22.8 20.0 - 27.0 Feldspar 0.2 - 2.4 mm Clinopyroxene 8.4 3.0 - 15.0 mostly 0.0.6 mm. Fe-Ti oxide 5.6 2.0 - 9.0 Amphiboles up to Amphibole 9.0 10.5 - 15.0 3.5 mm, other Olivine 0.8 0.80 - 1.0 minerals 0.3 - 0.6 mm. GROUNDMASS 57.4 54.5 - 63.5 0.01 - 0.2 mm. GROUNDMASS TEXTURE orthophyric. intersertal, pilotaxitic Table 3-49. Petrography of basaltsfrom Youn g Ungaran. Modal analyses are in volume %. PHENOCRYSTS GROUNDMASS Mean (33) Range Mean (4) Range Si02 51.84 45.2 - 62.51 52.10 47.88 - 55.42 A1203 30.25 21.48 - 34.83 29.70 26.90 - 32.98 FeO 0.82 0.28 - 2.21 1.05 0.85 - 1.37 MgO 0.11 0.02 - 0.68 0.16 0.09 - 0.30 CaO 12.85 6.59 - 18.21 12.27 9.80 - 16.08 Na20 3.53 1.42 - 5.91 3.90 1.93 - 4.60 K20 0.61 0.05 - 3.96 0.83 0.18 - 8.84 An 64.20 38.00 - 87.40 60.60 47.70 - 81.30 Ab 32.10 12.30 - 53.70 34.60 17.60 - 40.50 Or 3.74 0.29 - 27.20 4.80 1.08 - 52.40 Table 3-50. Chemical data for feldspar in basalts from Young Ungaran. 317 Core Rim Mean (12) Range Mean (11) Range SiO_ 53.19 45.19 - 62.51 51.49 46.44 - 57.19 Al^ 29.36 21.48 - 34.83 30.62 26.93 - 33.92 FeO 0.85 0.28 - 1.90 0.71 0.33 - 2.21 MgO 0.10 0.02 - 0.23 0.08 0.05 - 0.10 CaO 11.95 6.59 - 19.21 13.10 8.19 - 17.11 Na20 3.66 1.42 - 5.76 3.48 1.66 - 5.91 K20 0.91 0.05 - 3.96 0.50 0.12 - 1.43 An 60.40 38.00 - 87.40 65.39 41.70 - 84.20 Ab 33.87 12.30 - 53.20 31.53 14.90 - 53.70 Or 5.73 0.29 - 27.21 3.08 0.68 - 8.67 Table 3-51. Chemical data for feldspar phenocrysts in lava dome basalts from Young Ungaran. Core Rim Mean (4) Range Mean (5) Range Si0_ 50.10 48.75 - 50.89 50.85 49.01 - 52.34 A1203 31.36 31.04 - 32.15 30.63 29.77 - 32.23 FeO 0.73 0.52 - 0.96 1.06 0.57 - 2.21 MgO 0.09 0.02 - 0.14 0.19 0.04 - 0.68 CaO 14.24 13.67 - 15.37 13.34 12.39 - 14.78 Na20 3.14 2.94 - 3.37 3.54 2.96 - 4.05 K20 0.34 0.26 - 0.42 0.37 0.27 - 0.45 An 69.98 68.11 - 73.19 66.6 61.26 - 71.36 Ab 27.98 25.33 - 30.02 31.76 27.09 - 36.21 Or 2.02 1.47 - 2.48 2.18 1.55 - 2.81 Table 3-52. Chemical data for feldspar phenocrysts in lava flow basalts from Young Ungaran. 318 in so co co oo *o r-» oo Os co tr, o OO ON OO —i vo co co ^ —' —' co (U ___ oo T-. —<. oq i—i (N O to rt -H b^ io b NO o oo c CO —• O 00 cd oo in m ^f CN ON rr rr © 00 OS* •rt —; ON O OO i—• o 00 r- Tt WO 06 d c5 c5 CO CN b r~- ON q — (N rf CO od Q Z D O CO ON—' lO VO © rr r)- —I ON^ttO—1 oovor~OrrtnrrO(Nr-;coON c- ON'bcobodbcocoogj© ON O rt --> n Tt rr vo ON CO (N VO CO ON VO o Tj- —i CN r- CN ON r- ©r o ON -* Ti" CO CN VO CU CO so b CN rf -H Ebl to wo cd 00 0-, H r- © Tt r}- Tj" >-H rr o CN ON rf CN O O O rt ^ rr. eu CO b NO ON' ^H' rj-' CO O -H' od NO T-H bi > *° —' CN to rT c '•''iiiii 1 1 cd j>©©tOON!-H oo Sr^^^^^^VOON o CN cNr^oot^NqcNrtcNto I—H CO E T-H d ri od d co ri b r^ ON CO OS 10 CO HH (N rT r* o *«H , rnONVO , cd £~£,*- ' © o l-H o > OO OO r- I> N OO rt M (s VD to 1 CU CN © NO ON -1 co' CO © o © to" c -J 10 W "-i CN to rT l-H ba c '•'llllll 1 1 oba cd c -H©qNco^H(N •—s^ ii ^o r-NOcocorrrrtoONio r- oo G '-;r-;oovqcor^cNcN'-H t-H oo eu o bbco'odbco'cNo'od T-H G 2 •O I-H PHENOCRYSTS Lava flow Lava dome Mean (1) Mean (1) Si02 n.d 0.05 Ti02 11.92 6.22 A1203 4.37 1.55 FeO 76.68 84.38 MnO 0.62 0.76 MgO 1.75 1.31 CaO 0.03 0.05 Na20 0.03 0.03 Fe203 41.42 55.68 FeO 39.41 34.28 USP* 36.52 18.25 Table 3-55. Chemical data for Fe-Ti oxide in basalts of lava dome and lava flow from Young Ungaran. USP* = molecular percent ulvospinel. PHENOCRYSTS Mean (8) Minimum Maximum Si02 40.17 36.90 45.77 Ti0_ 2.46 1.61 4.62 A1203 13.76 10.06 14.89 Cr203 0.07 0.04 0.12 FeO 11.96 9.80 15.22 MnO 0.19 0.10 0.60 MgO 13.66 10.86 15.10 CaO 12.35 11.98 13.59 Na20 2.18 1.56 2.65 K20 1.05 0.39 1.25 Table 3-56. Chemical data for amphibole in basalts from Young Ungaran. 321 PHENOCRYSTS Mean (9) Minimum Maximum Si02 39.30 37.89 40.08 A1203 0.23 0.11 0.43 FeO 21.64 18.65 28.12 ! MnO 0.49 0.31 0.71 MgO 38.07 32.80 40.65 CaO 0.28 0.15 0.39 Fo 75.76 67.52 79.53 Fa 24.24 20.47 32.48 Table 3-57. Chemical data for olivine in basalts from Young Ungaran. Mean Range GRAIN SIZE (13) PHENOCRYSTS Plagioclase 24.4 20.0 - 29.0 feldspar 0.2 - 3.5 mm Clinopyroxene 6.1 3.0 - 9.0 mostly 0.6 - 1.2 mm. Fe-Ti oxide 6.6 3.0 - 12.0 Other minerals 0.3 - Amphibole 3.5 1.5 - 10.0 0.7 mm. Other 0.8 0.05 - 1.0 GROUNDMASS 59.8 55.0 - 66.0 0.01 - 0.2 mm. GROUNDMASS TEXTURE intersertal,intergranula r and p ilotaxitic Other = pseudomorphs after olivine. Table 3-58. Petrography of basaltic andesites from Young Ungaran. Modal analyses are in volume %. 322 PHENOCRYSTS GROUNDMASS Mean (10) Range Mean (7) Range 51.82 Si02 53.78 48.25 - 58.29 46.97 - 56.69 A1203 29.55 27.11 - 32.64 30.55 28.19 - 33.64 FeO 0.44 0.21 - 0.70 0.53 0.31 - 0.73 MgO 0.03 0.03 - 0.04 0.03 0.03 - 0.05 CaO 11.38 8.29 - 15.51 12.87 9.53 - 16.49 Na20 4.23 2.69 - 5.70 3.87 2.16 - 4.75 K20 0.59 0.18 - 1.74 0.33 0.13 - 0.50 An 57.40 43.87 - 75.30 63.37 50.91 - 80.25 Ab 39.10 23.60 - 52.30 34,69 19.02 - 45.91 Or 3.54 1.04 - 10.16 1.94 0.75 - 3.18 Table 3-59. Chemical data for feldspar in basaltic andesites from Young Ungaran. PHENOCRYSTS GROUNDMASS Mean (8) Range Mean (1) Si02 51.64 47.21 - 53.02 45.56 no. 0.28 0.10 - 1.14 1.65 A1203 1.63 0.70 - 6.76 8.52 Cr203 0.05 0.04- 0.11 0.04 FeO 8.88 8.39 - 9.41 8.28 MnO 0.86 0.25 - 1.10 0.13 MgO 13.78 12.79 - 14.97 12.35 CaO 22.54 21.99 - 22.98 23.20 Na20 0.35 0.13 - 0.52 0.26 Wo 47.34 45.90 - 51.36 54.26 En 40.21 38.83 - 43.48 40.21 Fs 12.45 7.68 - 14,61 5.53 Table 3-60. Chemical data for clinopyroxene in basaltic andesitesfrom Youn g Ungaran. 323 PHENOCRYSTS GROUNDMASS Mean (2) Range Mean (1) SiO_ 0.19 0.19 - 0.20 0.07 TiO_ 7.18 5.91 - 8.45 7.55 AI2O3 3.43 3.23 - 3.64 1.31 Cr203 0.03 n.d - 0.05 n.d FeO 80.32 79.51 - 81.14 82.28 MnO 0.79 0.64 - 0.93 0.49 MgO 1.71 1.49 - 1.92 1.21 CaO 0.31 0.14 - 0.48 0.24 Fe203 50.92 48.76 - 53.07 52.67 FeO 34.51 33.30 - 35.63 35.43 USP* 21.99 18.21 - 25.73 22.27 Table 3-61. Chemical data for Fe-Ti oxide in basaltic andesites from Young Ungaran. USP* = molecular ulvospinel. PHENOCRYSTS Mean (2) Range Si02 37.71 36.38- 39.04 Ti02 2.43 2.27 - 2.59 A1203 12.34 9.90- 14.79 Cr203 0.06 0.04 - 0.07 FeO 11.78 11.78- 11.79 MnO 0.21 0.12 - 0.30 MgO 12.73 12.02- 13.45 CaO 11.68 11.15- 12.20 Na20 2.16 2.13- 2.18 K20 1.23 1.20- 1.25 Table 3-62. Chemical data for amphibole in basaltic andesites from Young Ungaran. 324 Mean Range GRAIN SIZE (9) PHENOCRYSTS Plagioclase 22.9 18.0 - 27.0 Clinopyroxene 4.8 2.5 - 8.5 up to 3.2 mm but Fe-Ti oxide 4.2 3.0 - 6.0 mostly 0.4- 1.2 mm Amphibole 6.4 3.0 - 10.5 Mca 1.2 0.05 - 2.0 GROUNDMASS 61.6 60.0 - 65.0 0.01 - 0.2mm GROUNDMASS TEXTURE orthopyric, intersertal and pilotaxitic Table 3-63. Petrography of andesites from Young Ungaran. Modal analyses are in volume %. PHENOCRYSTS GROUNDMASS Mean (26) Range Mean (3) Range Si02 55.71 45.84 - 59.71 53.14 49.10 - 55.73 Al2(b 28.13 25.23 - 34.13 29.60 27.96 - 32.10 FeO 0.37 0.24 - 0.58 0.50 0.33 - 0.59 MgO 0.13 0.02 - 1.99 0.07 0.02 - 0.10 CaO 9.71 6.53 - 17.51 11.62 9.46 - 14.80 Na20 5.42 1.83 - 6.97 4.63 3.14 - 5.97 K20 0.54 0.09 - 0.96 0.45 0.22 - 0.59 An 48.18 32.20 - 83.70 56.50 45.30 - 71.40 Ab 48.63 15.80 - 62.20 40.85 27.30 - 51.70 Or 3.19 0.51 - 5.63 2.58 1.30 - 3.52 Table 3-64. Chemical data for plagioclase in andesites from Young Ungaran. 325 Core Rim Mean (12) Range Mean (11) Range Si02 54.83 45.84 - 57.72 56.24 51.94 - 59.71 AI2Q3 28.64 26.96 - 34.13 27.93 25.23 - 30.21 FeO 0.36 0.26 - 0.57 0.37 0.24 - 0.50 MgO 0.06 0.02 - 0.10 0.04 0.02 - 0.09 CaO 10.45 8.38 - 17.51 9.28 6.53 - 12.62 Na20 5.17 1.83 - 6.28 5.56 3.60 - 6.97 K_0 0.48 0.09 - 0.71 0.59 0.33 - 0.96 An 51.20 41.90 - 83.70 46.42 32.20 - 60.40 Ab 46.00 15.80 - 54.70 50.67 37.80 - 62.20 Or 2.80 0.51 - 4.26 3.51 1.90 - 5.60 Table 3-65. Chemical data for cores and rims of plagioclase phenocrysts in andesites from Young Ungaran. PHENOCRYSTS GROUNDMASS Mean (10) Range Mean (1) Si02 52.08 51.13 - 52.92 52.06 T102 0.17 0.10 - 0.32 0.35 1.31 Al203 1.40 1.14 - 1.83 Cr203 0.07 0.04 - 0.1 0.04 FeO 8.95 8.16 - 9.70 8.61 MnO 0.87 0.68 - 1.02 1.00 MgO 13.50 12.50 - 14.32 14.00 CaO 22.62 21.77 - 23.18 22.39 0.24 Na20 0.34 0.13 - 0.44 Wo 47.19 45.48 - 48.38 46.64 En 39.18 36.16 - 41.78 40.54 Fs 13.63 10.64 - 16.19 12.82 J Table 3-66. Chemical data for clinopyroxene in andesites from Young Ungaran. 326 PHENOCRYSTS GROUNDMASS Mean (4) Range Mean (2) Range Si02 0.25 n.d - 0.80 0.92 0.87 - 0.98 Ti02 9.44 7.76 - 11.76 8.21 7.98 - 8.43 A1203 2.37 1.77 - 3.35 0.97 0.92 - 1.02 Cr203 0.16 n.d - 0.24 0.18 0.16 - 0.20 FeO 79.94 74.40 - 83.06 84.16 84.00 - 84.32 MnO 0.80 0.55 - 1.01 0.68 0.68 - 0.68 MgO 0.96 0.53 - 1.94 0.25 0.20 - 0.30 CaO 0.59 n.d - 2.30 0.38 0.16 - 0.61 Fe203 47.39 43.35 - 51.92 50.00 49.70 - 50.30 FeO 37.30 35.37 - 40.56 39.17 38.74 - 39.60 USP* 28.51 23.00 - 35.16 24.70 24.08 - 25.32 Table 3-67. Chemical data for Fe-Ti oxide in andesitesfrom Youn g Ungaran. USP* = molecular percent ulvospinel. PHENOCRYSTS Mean (14) Minimum Maximum Si02 40.53 36.03 42.25 TiO_ 2.30 1.78 4.46 l A1203 12.21 9.38 15.46 Cr203 0.05 0.04 0.11 FeO 13.28 10.84 15.25 MnO 0.39 0.12 0.68 MgO 13.00 11.37 14.08 CaO 11.76 11.37 12.40 Na20 1.93 0.66 2.26 K20 1.05 0.96 1.25 Table 3-68. Chemical data for amphibole in andesites from Young Ungaran. 327 PHENOCRYSTS Mean (2) Minimum Maximum Si02 35.08 34.56 35.60 Tifjvj 4.74 4.70 4.77 A1203 14.58 14.25 14.91 FeO 16.22 16.06 16.38 MnO 0.28 0.26 0.29 MgO 14.06 13.77 14.35 CaO 0.02 0.02 0.02 Na20 0.76 0.76 0.76 K20 9.27 9.21 9.33 Table 3-69. Chemical data for mica in andesites from Young Ungaran. Basalt Basaltic andesite Andesite Mean (18) Mean (22) Mean (17) Plagioclase 23.0 24.2 23.9 Clinopyroxene 9.4 7.2 5.5 Fe-Ti oxide 5.8 5.5 4.8 Amphibole 2.4 1.8 4.7 Mica - .1 0.6 i Olivine 0.4 0.5 0.1 Total phenocryst 41.9 40.0 39.4 Table 3-70. Modal contents (in volume %) of phenocrysts in rocks from Ungaran. 328 PHENOCRYSTS GROUNDMASS Mean (68) Range Mean (13) Range 43.96 - 62.51 50.87 45.54 - 57.66 Si02 49.96 30.80 25.50 - 34.66 A1203 31.48 21.48 - 35.95 FeO 0.79 0.28 - 2.98 0.89 0.52 - 1.82 MgO 0.14 0.02 - 2.47 0.10 0.02 - 0.30 CaO 14.27 6.59 - 19.04 13.09 7.36 - 17.00 1.85 - 4.84 Na20 2.97 0.30 - 15.91 3.48 0.14 - 3.16 K20 0.41 0.05 - 3.96 0.77 An 70.80 38.00 - 96.90 64.30 37.00 - 82.90 Ab 26.70 2.80 - 53.70 31.00 16.30 - 44.60 Or 2.50 0.23 - 27.21 4.62 0.81 - 19.10 Table 3-71. Chemical data for feldspar in basalts from Ungaran volcano. PHENOCRYSTS GROUNDMASS Mean (86) Range Mean (27) Range Si02 51.73 43.76 - 64.67 51.16 45.19 - 57.36 A1203 30.32 10.89 - 35.66 30.82 26.74 - 34.72 FeO 0.67 0.21 - 1.62 0.68 0.31 - 1.60 MgO 0.08 0.02 - 0.51 0.06 0.03 - 0.27 CaO 12.82 5.42 - 19.30 13.28 8.38 - 18.04 Na20 3.64 0.77 - 13.04 3.85 1.31 - 6.33 K20 0.73 0.04 - 4.03 0.35 0.07 - 0.85 An 63.40 25.27 - 93.00 65.40 40.43 - 88.60 Ab 32.20 6.80 - 72.10 32.61 11.60 - 55.30 Or 4.40 0.23 - 23.90 1.99 0.40 - 4.91 Table 3-72. Chemical data for feldspar in basaltic andesites from Ungaran volcano. 329 PHENOCRYSTS GROUNDMASS Mean (48) Range Mean (7) Range SiO_ 53.81 43.36 - 59.71 53.30 44.71 - 61.21 AI2Q3 29.25 25.83 - 36.12 29.40 23.70 - 34.89 FeO 0.44 0.24 - 1.42 0.55 0.33 - 0.71 MgO 0.10 0.02 - 1.99 0.06 0.02 - 0.10 CaO 11.12 6.53 - 19.12 11.63 6.56 - 18.08 Na20 4.79 0.85 - 6.97 4.38 1.44 - 6.56 K20 0.49 0.04 - 0.99 0.67 0.10 - 2.17 An 54.50 32.20 - 92.24 56.90 37.4 - 87.24 Ab 42.60 7.42 - 62.20 38.9 12.24 - 52.40 Or 2.90 0.23 - 5.80 7.5 0.52 - 13.46 Table 3-73. Chemical data for feldspar in andesites from Ungaran volcano. Average value forj phenocrysts Average value for groundmass Oldest Old P. Cones Young Oldest Old P. Cones Young (11) (19) (5) (33) (2) (6) (1 (4) SiO_ 46.68 48.46 50.45 51.84 51.25 50.92 49.36 52.10 M203 33.20 32.63 31.42 30.25 30.08 30.90 32.11 29.70 FeO 1.05 0.63 0.62 0.82 1.28 0.74 0.66 1.05 MgO 0.36 0.07 0.06 0.11 0.18 0.04 0.03 0.16 CaO 16.78 15.41 13.72 12.85 12.36 13.13 14.32 12.27 3.51 3.24 3.90 Na20 1.72 2.56 3.51 3.53 3.19 0.76 0.27 1.83 K20 0.19 0.24 0.23 0.61 1.65 An 83.4 75.86 67.4 64.2 61.0 64.3 69.84 60.60 Ab 15.5 22.76 31.30 32.1 29.0 31.2 28.59 34.60 Or 1.18 1.38 1.3 3.74 10.0 4.5 1.57 4.80 Table 3-74. Chemical data for feldspar in basalts from Oldest to Young Ungaran volcanic rocks. 330 Average value for phenocryst s Average value for groundmass Old P. Cones Young Old P. Cones Young (6) (70) (10) (3) (15) (7) 53.78 49.91 54.69 51.82 Si02 49.34 51.64 31.55 27.99 30.55 A1203 32.04 30.29 29.55 FeO 0.66 0.70 0.44 0.72 0.64 0.53 MgO 0.05 0.09 0.03 0.05 0.07 0.03 CaO 14.53 17.76 11.38 14.19 13.23 12.87 4.00 3.87 Na20 3.10 3.60 4.23 3.25 2.55 0.33 K20 0.26 0.79 0.59 0.33 An 71.06 69.70 57.40 69.30 65.74 63.37 Ab 27.40 27.70 39.10 28.80 32.05 34.69 Or | 1.54 4.70 3.54 1.90 2.23 1.94 Table 3-75. Chemical data for feldspar in basaltic andesites from Oldest to Young Ungaran. Average value for phenocrysts Avera ge value for groundmass Oldest Old P. Cones Young Oldest Old P. Cones Young (6) (3) (13) (26) (2) (D (D (3) Si02 44.61 51.91 55.42 55.71 45.05 53.82 61.21 53.14 A1203 35.67 30.38 28.08 28.13 34.86 29.02 23.70 29.60 FeO 0.73 0.48 0.44 0.37 0.68 0.47 0.66 0.50 MgO 0.10 0.05 0.06 0.13 0.04 0.02 0.09 0.07 CaO 18.03 12.18 9.97 9.71 17.78 10.86 6.56 11.62 Na20 1.35 4.65 5.41 5.42 1.46 5.32 5.57 4.63 K20 0.20 0.36 0.62 0.54 0.10 0.49 2.17 0.45 An 87.50 57.96 48.60 48.18 86.70 51.54 34.13 56.50 Ab 11.90 40.00 47.80 48.63 12.72 45.69 52.40 40.85 Or 0.60 2.04 3.60 3.19 0.59 2.77 13.46 2.58 Table 3-76. Chemical data for feldspar in andesites from Oldest to Young Ungaran. 331 .—_ Phenocrysts Old Ungaran Parasitic Cones Young Ungaran Zoning predominantly normal normal, reverse and oscillatory predominantly reverse An range small (An^i to Angj) wide (An25 to Anc>3) small (Ari44toAn75) Core comp. mostly bytownite mostly labradorite & bytownite mostly labradorite Table 3-77. Significant differences in compositions of plagioclase phenocrysts in basaltic andesites from Old Ungaran, Parasitic Cones and Young Ungaran. Phenocrysts Groundmass Mean (60) Range Mean (6) Range Si02 50.69 44.48 - 53.26 49.91 48.28 - 51.85 TiO_ 0.51 0.10 - 1.51 0.69 0.15 - 1.13 AI2O3 3.53 0.54 - 9.74 3.71 0.95 - 6.18 Cr203 0.09 0.04 - 0.30 0.05 0.04 - 0.11 FeO 8.60 6.93 - 9.91 8.61 7.82 - 9.35 MnO 0.48 0.10 - 1.23 0.44 0.19 - 1.11 MgO 13.57 11.44 - 14.72 13.99 13.04 - 15.29 CaO 22.24 19.27 - 23.64 22.25 20.45 - 22.93 Na20 0.29 0.13 - 1.26 0.35 0.36 - 0.46 Wo 47.84 43.20 - 56.20 48.44 39.46 - 51.33 En 40.46 35.79 - 45.53 42.33 39.50 - 45.77 Fs 11.65 2.97 - 16.10 9.22 7.34 - 13.08 Table 3-78. Chemical data for clinopyroxene in basalts from Ungaran. 332 Phenocrysts Groundmass Mean (23) Range Mean (5) Range 47.21 - 53.02 ; 49.73 45.56 - 51.63 Si02 50.78 Tif^ 0.42 0.10 - 1.14 0.69 0.26 - 1.65 3.44 1.79 - 8.52 A1203 2.66 0.70 - 6.76 0.04 0.04 - 0.05 Cr203 0.05 0.04 - 0.21 FeO 8.45 6.51 - 9.41 9.51 8.22 - 12.92 MnO 0.64 0.15 - 1.10 0.46 0.13 - 0.62 MgO 14.14 12.79 - 15.45 14.24 12.35 - 15.49 CaO 22.52 21.18 - 23.86 21.61 20.10 - 23.20 0.21 - 0.35 Na20 0.33 0.13 - 0.52 0.29 Wo 48.12 45.01 - 54.56 46.56 42.87 - 54.26 En 41.98 38.83 - 45.02 42.49 39.52 - 43.62 Fs 9.22 2.82 - 14.61 10.96 5.53 - 10.10 Table 3-79. Chemical data for clinopyroxene in basaltic andesites from Ungaran. Phenocrysts Groundmass Mean (24) Range Mean (3) Range Si02 50.97 47.80 - 52.92 50.84 49.37 - 52.06 Ti02 0.38 0.10 - 1.03 0.52 0.34 - 0.88 A1203 2.41 0.87 - 7.08 2.48 1.31 - 4.13 Cr203 0.05 0.03 - 0.11 0.04 0.04 - 0.04 FeO 8.91 7.93 - 10.80 8.68 8.29 - 9.14 MnO 0.67 0.13 - 1.08 0.64 0.26 - 1.00 MgO 14.00 12.73 - 15.80 14.52 14.00 - 14.98 CaO 22.22 20.85 - 23.39 21.93 21.32 - 22.39 Na20 0.37 0.13 - 0.64 0.34 0.24 - 0.43 Wo 47.33 43.22 - 52.13 46.78 45.03 - 48.67 En 41.22 36.18 - 45.93 43.08 40.54 - 44.72 Fs 12.20 5.29 - 16.42 10.15 6.62 - 12.82 Table 3-80. Chemical data for clinopyroxene in andesites from Ungaran. 333 Phenocrys ts Core Rim Mean (28) Range Mean (31) Range Si02 50.29 44.48 - 53.26 50.99 46.79 - 53.23 Ti02 0.59 0.10 - 1.51 0.42 0.10 - 1.13 A1203 3.80 0.70 - 9.74 3.06 0.54 - 7.47 Cr203 0.08 n.d - 0.11 0.10 n.d - 0.30 FeO 8.67 7.21 - 9.69 8.61 7.14 - 9.91 MnO 0.44 0.12 - 1.02 0.51 0.10 - 1.23 MgO 13.62 11.44 - 14.64 13.61 11.52 - 14.72 CaO 22.22 20.98 - 23.29 22.41 20.82 - 23.64 Na20 0.29 0.13 - 0.49 0.25 0.13 - 1.26 Wo 48.99 44.04 - 56.20 47.60 43.95 - 53.93 En 30.36 35.79 - 43.96 40.18 35.85 - 44.20 Fs 14.40 3.95 - 16.10 11.86 2.97 - 15.73 Table 3-81. Chemical data for cores and rims of clinopyroxene phenocrysts in basalts from Ungaran. Phenocrysts Core Rim Mean (12) Range Mean (12) Range SiO_ 50.70 47.21 - 52.44 50.86 48.43 - 53.02 T1O2 0.43 0.12 - 1.14 0.41 0.10 - 0.78 AI2O3 2.73 0.71 - 6.76 2.60 0.70 - 5.49 Cr203 0.04 n.d - 0.06 0.06 n.d - 0.21 FeO 8.47 7.41 - 9.41 8.44 6.51 - 9.13 MnO 0.66 0.15 - 1.10 0.62 0.16 - 1.10 MgO 14.11 12.79 - 15.45 14.16 13.47 - 14.97 CaO 22.50 21.18 - 23.86 22.54 21.61 - 23.65 0.13 - 0.38 Na20 0.36 0.25 - 0.52 0.31 Table 3-82. Chemical data for cores and rims of clinopyroxene phenocrysts in basaltic andesites from Ungaran. 334 ba c D 6 okH Ca-H lO ON 00 CN CO oo r-H © OO CO ON r-H OO CO CO D © © © rr a—» cN r-H © i-H to* CO* © "c/S r-* © i—H 0) to T-H CN CN ON VO CN NO rT CO NO to -G T—1 ON oo c q co rT © NO r-; CO CO PCUH T-H © CO CN* _ b ri © od r-H © o to CN y\ in cd CH a— CU CaO o o .5 i-H O &o -cC in On NO © to i-H ON CN © ON rT oo q oo I-H VO © oo © vo B CN i—i to © © i-H to CO © "C D WO l-H i-H CN T3 C cd • i 1 1 1 1 1 1 1 sin Ott, — © NO to CO O o rT CO ON i-H V. r-H oo r-H g oo r-H ON o t-* © r-H c r-* © ri © © £ rT i-H CN cd /—„ td CN T_ r-H IS oo r-H rT OO VO rT o oo o rT t-- CN oo ON O © ON l> ro rT t~~; VO ON ON oo rT VD r- l> co D CN* © CN © CN © to —I rr' to to l-H r-H CN b bJO| rT r" C rr cd OO r-H to rT CO © CO r- Oa -a CN NO co CN CO o rT oo oo ON* ©' —* © OO © CO © ON CN* b rT CN CO rr so rT NO oo i—i co vo rT CO CN oo CN o rT VO oo © CO © oo „ © ©CN ON © rT to o © rT CO CN CU CN rr rr NO CO oo i—' © co oo oo CN r- CN OO CN ON r^ CN © >o ON rT co *-H C-o. O O i-H rr CO CO NO CU b © to CN >o rr -H W) i c o rT CO CO CO CN OO CO ON co to to ON cd i-H to o -H © oo © r>* © "H to tco —- C- r-H bCN rr b © rT CO O lO CN CN OO lO © NO rr r- © ON -H G tO CO CN © OO r- VD CO CN ON OO CN cd -H' © CN* © od CO CN © NO ON CO © to rt©CNONONVOVO©cOOO NO r^corr^orrooncNONr- OCN I-H ON © ON O to CO NO lO ON bD{ tO l-H cN tO rT C cd OO NO CN rT I-H © rT rT CO I-H CO CN P< rT CN ON © to r-1 rr © ^H T-H OO OO rr © -+ © vd » • * © W-i VD CN* rT © r-H r-H rT co T-H CN VO r-H tO CN ON r~ vo to OO NO ON oo CO ON VO t> r-; © CN| CN CO © CO* CN © oo o cd __ © rT © OO © r-H cN © >o CN rT JN JfN § O « Q Pr, © Oldest Ungaran Old Ungaran Parasitic Cones Young Ungaran Mean (7) Mean (17) Mean (6) Mean (30) 47.56 51.00 Si02 50.27 51.33 Ti02 0.58 0.45 0.97 0.44 A1203 3.66 3.36 7.05 2.90 Cr203 0.08 0.09 0.98 0.09 FeO 8.51 8.53 7.97 8.79 MnO 0.25 0.42 0.18 0.63 MgO 14.10 19.92 12.9 13.58 CaO 21.10 21.57 23.00 22.54 Na20 0.44 0.33 0.23 0.25 Wo 48.11 46.11 52.25 47.87 En 42.68 41.46 40.67 39.45 Fs 9.22 12.43 7.08 12.68 Table 3-85. Chemical data for clinopyroxene phenocrysts in basalts from Oldest to Young Ungaran. Old Ungaran Parasitic Cones Young Ungaran Mean (9) Mean (6) Mean (8) Si02 49.80 51.12 51.64 Tif^ 0.60 0.34 0.28 A1203 3.98 2.06 1.63 FeO 8.06 8.48 8.87 MnO 0.35 0.76 0.86 MgO 14.38 14.26 13.77 CaO 22.43 22.61 22.54 Na20 0.32 0.33 0.35 Wo 49.06 47.69 47.34 En 43.65 41.82 40.21 Fs 7.08 10.49 12.45 Table 3-86. Chemical data for clinopyroxene phenocrysts in basaltic andesites from Old to Young Ungaran. 337 Oldest Ungaran Old Ungaran Parasitic Cones Young Ungaran Mean (3) Mean (5) Mean (6) Mean (10) SiO_ 49.49 51.20 49.92 52.08 TiC_ 0.75 0.34 0.52 0.17 AI2O3 3.99 2.05 3.40 1.40 Cr203 0.04 0.04 0.05 0.07 FeO 8.12 8.90 9.36 8.95 MnO 0.26 0.67 0.59 0.87 MgO 14.79 15.25 13.14 13.50 CaO 22.14 21.09 22.71 22.62 Na20 0.42 0.44 0.31 0.34 Wo 48.77 44.60 49.13 47.19 En 45.15 44.98 39.54 39.18 Fs 6.07 10.42 11.32 13.63 Table 3-87. Chemical data for clinopyroxene phenocrysts in andesites from Oldest to Young Ungaran. Phenocryst Groundmass Mean (9) Range Mean (4) Range Si02 0.05 n.d - 0.07 0.20 n.d - 0.47 TiCb 10.67 6.22 - 14.77 11.86 3.37 - 18.92 A1203 3.96 1.55 - 5.73 2.00 0.32 - 4.34 Cr203 0.08 n.d - 0.12 0.07 n.d - 0.07 FeO 77.84 74.84 - 84.38 79.26 74.34 - 87.84 MnO 0.67 0.49 - 0.85 0.55 0.26 - 0.71 MgO 2.01 0.81 - 3.06 1.09 0.25 - 1.96 CaO 0.05 n.d - 0.05 0.20 0.07 - 0.48 Fe203 44.47 36.83 - 55.68 43.70 30.90 - 60.60 FeO 37.82 34.05 - 42.05 39.98 33.34 - 46.52 USP* 32.47 18.25 - 44.49 35.10 10.00 - 55.00 Table 3-88. Chemical data for Fe-Ti oxide in basalts from Ungaran. USP* = molecular percent ulvospinel. 338 Phenocryst Groundmass Mean (8) Range Mean (5) Range n.d - 0.14 SiO_ 0.12 n.d - 0.20 0.08 7.55 - 16.46 Ti02 9.03 5.91 - 12.19 11.81 1.78 1.31 - 2.52 A1203 3.57 1.81 - 4.66 0.06 n.d - 0.07 Cr203 0.08 n.d - 0.13 FeO 79.65 77.69 - 81.17 79.55 76.90 - 82.82 MnO 0.68 0.58 - 0.93 0,61 0.49 - 0.69 MgO 1,65 0.99 - 2.05 1.17 0.83 - 1.37 CaO 0.17 0.09 - 0.25 0.12 0.06 - 0.22 Fe203 47.73 41.96 - 53.07 44.27 35.83 - 52.67 FeO 36.70 33.39 - 39.93 39.72 35.43 - 44.66 USP* 27.38 18.21 - 36.73 34.80 22.30 - 47.90 Table 3-89. Chemical data for Fe-Ti oxide in basaltic andesites from Ungaran. USP* = molecular percent ulvospinel. Phenocryst Groundmass Mean (8) Range Mean (5) Range Si02 0.26 n.d - 0.82 0.42 0.06 - 0.98 TMh 10.03 7.58 - 12.30 9.37 7.98 - 11.20 A1203 2.79 1.14 - 4.58 1.90 0.92 - 3.60 Cr203 0.12 n.d - 0.24 0.05 n.d - 0.06 FeO 79.10 74.40 - 83.60 81.59 78.05 - 84.32 MnO 0.71 0.48 - 1.01 0.65 0.50 - 0.78 MgO 1.54 0.53 - 2.43 1.69 1.24 - 2.20 CaO 0.53 n.d - 2.40 0.24 0.07 - 0.61 Fe203 46.41 42.56 - 52.24 48.16 45.71 - 50.30 FeO 37.34 33.77 - 40.56 38.25 37.10 - 39.60 USP* 30.19 22.48 - 35.81 27.96 24.08 - 32.73 Table 3-90. Chemical data of Fe-Ti oxide in andesites from Ungaran. USP* = molecular percent ulvospinel. 339 Phenocryst Mean (21) Range Si 5.95 5.27 - 6.34 Al 2.04 1.66 - 2.43 Ti 0.29 0.20 - 0.49 Al 0.27 0.00 - 0.54 Cr 0.01 0.005 - 0.014 Fe3+ 0.49 0.00 - 0.91 Fe2+ 0.99 0.56 - 1.51 Mn 0.03 0.01 - 0.08 Mg 2.93 2.62 - 3.32 Ca 1.91 1.78 - 2.00 Nan 0.09 0.00 - 0.22 NaA 0.58 0.44 - 0.79 K 0.21 0.07 - 0.26 Table 3-91. Numbers of ions in formulae of amphibole phenocrysts in basalts from Ungaran. Numbers of ions are calculated on the basis of 23 oxygen atoms. Phenocryst Mean (6) Range Si 5.84 5.74 - 6.07 Al 2.15 1.92 - 2.26 Ti 0.24 0.18 - 0.29 Al 0.25 0.03 - 0.38 Cr 0.005 0.005- 0.009 Fe3+ 0.92 0.37 - 0.85 Fe2+ 0.99 0.78 - 1.27 Mn 0.03 0.01 - 0.04 Mg 2.95 2.82 - 3.06 Ca 1.96 1.90 - 2.00 Nas 0.04 0.00 - 0.10 0.57 - 0.70 NaA 0.61 K 0.24 0.19 - 0.30 Table 3-92. Numbers of ions in formulae of amphibole phenocrysts in basaltic from Ungaran. Numbers of ions are calculated on the basis of 23 oxygen atoms 340 Phenocryst Mean (21) Range Si 5.97 5.31 - 6.35 Al 2.07 1.65 - 2.45 Ti 0.28 0.20 - 0.49 Al 0.19 0.00 - 0.48 Cr 0.007 0.005- 0.013 Fe3+ 0.55 0.00 - 0.76 Fe2+ 1.02 0.62 - 1.82 Mn 0.04 0.01 - 0.09 Mg 2.92 2.60 - 3.10 Ca 1.83 0.01 - 2.00 NaB 0.09 0.00 - 0.21 0.00 - 0.76 NaA 0.51 K 0.30 0.19 - 1.82 Table 3-93. Numbers of ions in formulae of amphibole phenocrysts in andesites from Ungaran. Numbers of ions calculated on the basis of 23 oxygen atoms. Mg/Mg+Fe2+ Calculated equilibrium liquid S ample Grain Spot Olivine KD = 0.3 KD = 0.4 Total Total rock A rock B 921 1 core 0.58 0.39 0.46 1 921 1 rim 0.59 0.30 0.37 0.50 0.47 921 1 core 0.67 0.38 0.45 Table 3-94. Comparison of Mg/Mg + Fe2+ for olivines, calculated equilibrium liquids and host basalts for Oldest Ungaran. For total rock A and B, FeO = 0.80 and 0.90 total Fe as FeO respectively. 341 Mg/Mg+Fe2+ Calculated equilibrium liquid S ample Grain Spot Olivine KD = 0.3 KD = 0.4 Total Total rock A rock B 826 1 core 0.70 0.41 0.48 . 0.48 0.46 826 1 rim 0.62 0.33 0.39 1 832 1 core 0.68 0.39 0.46 1 832 1 rim 0.68 0.39 0.46 832 2 core 0.69 0.38 0.47 0.44 0.42 832 2 rim 0.67 0.38 0.45 832 3 core 0.68 0.39 0.46 832 3 rim 0.68 0.39 0.46 922 1 core 0.68 0.39 0.46 922 1 core-rim 0.67 0.38 0.45 0.46 0.44 922 1 rim 0.65 0.36 0.43 1 Table 3-95. Comparison of Mg/Mg + Fe2+ for olivines, calculated equilibrium liquids and host basalts for Old Ungaran. For total rock A and B, FeO = 0.80 and 0.90 total Fe as FeO respectively. Mg/Mg+Fe2+ Calculated equilibrium liquid Sample Grain Spot Olivine KD = 0.3 KD = 0.4 Total Total rock A rock B 428 1 rim 0.89 0.71 0.76 1 428 1 core-rim 0.88 0.69 0.75 0.45 0.43 428 1 core 0.89 0.71 0.76— 917 1 core 0.70 0.41 0.48 917 1 rim 0.65 0.36 0.43 0.51 0.48 917 2 core 0.57 0.28 0.35 917 2 rim 0.61 0.32 0.38 — Table 3-96. Comparison of Mg/Mg + Fe2+ for olivines, calculated equilibrium liquids and host basalts of Parasitic Cones. For total rock A and B, FeO = 0.80 and 0.90 total Fe as FeO respectively. 342 Mg/Mg+Fe2+ Calculated equilibrium liquid Sample Grain Spot Olivine KD = 0.3 KD = 0.4 Total Total rock A rock B 824 1 core 0.74 0.46 0.53—| 824 1 rim 0.74 0.46 0.53 824 2 core 0.74 0.46 0.53 0.52 0.50 824 3 core 0.68 0.39 0.46 320 1 core 0.79 0.53 0.60 — 0.49 0.46 320 1 rim 0.77 0.50 0.57— 326 1 core 0.80 0.55 0.62 326 2 core 0.79 0.53 0.60 0.54 0.51 326 1 rim 0.77 0.50 0.57 Table 3-97. Comparison of Mg/Mg+Fe2+ for olivines, calculated equilibrium liquids and host basalts for Young Ungaran. For total rock A and B, FeO = 0.80 and 0.90 total Fe as FeO respectively. Rock type Rim Core Total n 8 4 12 Basalts mean temp. 946 995 962 range 905 - 979 950 - 1036 905 - 1036 n 7 4 11 Basalts andesites mean temp. 773 935 826 range 695 - 910 930 -1020 695 -1020 n 10 6 16 Andesites mean temp. 866 886 874 range 890 -1059 801 -1066 801 -1066 Table 3-98. Calculated temperature (°C) of formation of clinopyroxene from Ungaran. Computation is carried out using method of Lindsley (1983). 343 CN to CN to tO _ co r- TT ON CN to tO CN rT ' ON to ON ON VO CO CO ON (N ON ON ON O NO VO to "O © CN °s ON OO ON oo to CN rT ON © I rT ON ON CO © ON _ ON CO CO ON ON (D tu cu C c cd cd kH in Number of Average of Standard Range values input values deviation Maximum Minimum Si02 4 50.60 .96 51.38 49.39 Ti02 4 0.98 .08 1.08 .88 AI2O3 4 19.12 .75 20.12 18.39 FeO* 4 9.71 .38 10.32 9.46 MgO 4 4.10 .47 4.59 3.50 MnO 4 .18 .03 .20 .13 CaO 4 9.02 .50 9.59 8.40 Na20 4 2.48 .25 2.70 2.12 K20 4 2.45 .30 2.74 2.02 P2O5 4 .36 .02 .39 .34 LOI 4 1.0 .27 1.64 1.08 Total 4 99.53 .03 99.41 100.35 Fe203/FeO 4 1.09 .09 1.15 .96 K20/Na20 4 .99 .04 1.02 .95 Mg-number 4 .48 .02 .50 .45 D.I 4 35.50 3.93 39.10 29.90 Rb 4 64 13.21 78 51 Sr 4 481 45.50 523 424 Zr 4 131 24.29 154 105 Nb 4 11 .80 12 10 Pb 4 17 5.80 25 14 Th 4 8 2.35 11 6 Y 4 28 3.80 31 24 Cr 13 V 286 Sc 22 Co 35 La 24 Ce 48.80 Sm 4.84 Eu 1.48 Yb 2.19 Lu 0.32 Hf 2.60 Ba 420 Zn 101 Ta 0.41 Table 4-1. Whole-rock geochemical data for basalts from Oldest Ungaran. 345 Number of Mean values Si02 60.80 TiO_ 65 AI2O3 18.69 FeO* 6.24 MgO 1.57 MnO .15 CaO 5.14 Na20 2.93 K20 3.08 P2O5 .27 LOI .78 Total 100.22 Fe203/FeO 2.03 K20/Na20 1.05 Mg-number .36 D.I 58.70 Rb 103 Sr 408 Zr 165 Nb 15 Pb 23 Th 15 Y 39 Cr 9 V 124 Sc 10 Co 39 La 39.20 Ce 56 Sm 4.83 Eu 1.36 Yb 2.69 Lu 0.42 Hf 3.90 Ba 590 Zn 77 Ta 0.70 Table 4-2. Whole-rock geochemical data for andesite from Oldest Ungaran. 346 O > m o CN o rT rT cj in CO CN in O. ON 00 Os ON CN CM E < oo VO rT x r- o o NO r~- vO >n ro CN CN ro rT Ua CO NO in X ON c rt CN D. rj- CO t-~ u NO ro CN V NO CN cd O 00 ro oc Sa CO in o oo CN CO —• i i in rr NO ro o NO rT ro 3 ro ON O X) ON in CO in t— r- r- rT CO Oa rT i rT in in CO CO oo 00 vO ON CN 3 ON oo CN CN CN CM o o ON NO rT • ON 1 O oo ON i 00 ON CN o CO o CO in r- r- 00 CU r- ON CO CN CN ON ON ro vO ON 00 in ON 3 in N- in i 1 f- in o rT oo CN ON oo 00 (N rr oo CN ro o ON CO in O NO oo CO CM CM CN CN ro 1 CN 1 in NO in VO O ON i i • i 1 00 i—a _> ON NO rT ON CN ON oc C~- 8 t-~ t— 00 ON o r— in NO t-H CO ON ON oo ON oo oo 1 oo 3 i oo in a; • i t in oo ON o in oo vO vO ON ON vO CN ON o in ro (N ro rT ro oo CN £ vo O Vl oo NO CN vo CN t— rT CO 00 NO Os vo 3 oo a—1 CO O ON 00 00 oo oo vn in ro o N" r- rT NO * ON rT oo oo o oo ON 00 m VO in CS NO VO ON rT CN Os t— o co Number of Average of Standard Ran PP. 1 values input values deviation Maximum Minimum Si02 6 51.08 .91 51.92 49.70 Tif^ 6 .95 .09 1.06 .80 A1203 6 19.49 .30 20.80 18.80 FeO* 6 9.23 .30 9.61 8.61 MgO 6 3.80 .49 4.15 2.98 MnO 6 .18 .01 .20 .17 CaO 6 8.69 .50 9.11 7.60 Na20 6 3.07 .26 3.35 2.65 K20 6 2.27 .40 2.79 1.64 P2O5 6 .35 .05 .40 .29 LOI 6 .90 .17 1.05 .66 Total 6 99.60 .09 100.21 99.51 Fe203/FeO 6 1.50 .68 2.87 .97 K20/Na20 6 .30 .15 .89 .49 Mg-number 6 .47 .04 .50 .40 D.I 6 41.60 4.01 47.00 36.10 Rb 6 63 13.90 81 40 Sr 6 517 99.69 678 415 Zr 6 137 18.03 155 105 Nb 6 11 2.10 14 8 Pb 6 18 7.11 31 10 Th 6 9 4.90 14 2 Y 6 29 3.95 35 25 Cr 4 11 3.97 16 7 V 4 246 16.70 262 225 Sc 4 20 2.16 23 18 Co 4 34 4.73 40 29 La 4 35.40 13.10 48.60 17.90 Ce 4 64.80 20.20 85.40 37.80 Sm 4 6.22 1.16 7.40 4.63 Eu 4 1.87 .33 2.28 1.48 Yb 4 2.61 .19 2.85 2.45 Lu 4 .42 .04 .46 .37 Hf 4 3 .18 3.20 2.80 Ba 4 549 31.20 598 530 Zn 4 143 33.10 185 105 |Ta 3 .52 .34 .78 0.24 1 Table 4-4. Whole-rock geochemical data for basalts from Old Ungaran. 348 Number of Average ot Standard Range values input values deviation Maximum Minimum 53.40 .47 53.95 52.91 Si02 4 Ti02 4 .78 .04 .80 .70 .17 19.30 18.90 A1 0 4 19.15 2 3 8.28 .39 8.85 7.73 FeO* 4 MgO 4 3.26 .29 3.50 2.88 MnO 4 .18 .02 .20 .15 CaO 4 8.49 .07 8.56 8.40 3.50 2.39 Na20 4 2.87 .47 2.65 2.44 K20 4 2.58 .09 - — ^,v 4 .30 .03 .35 .27 P2OLOI5 4 0.69 .31 .97 .45 Total 4 99.66 .09 100.21 99.58 2.57 1.18 Fe203/FeO 4 1.68 .60 K20/Na20 4 .91 .10 1.02 .75 Mg-number 4 .46 .02 .48 .45 0 41.93 3.40 46.20 38.10 D.I 4 Rb 4 66 5.95 71 58 Sr 4 537 81.80 645 458 Zr 4 135 15.70 158 124 Nb 4 12 3.00 16 9 Pb 4 15 1.14 16 13 Th 4 8. 1.00 9 7 Y 4 29 4.09 35 26 Cr 2 22 13.50 36 9 V 2 201 13.50 215 188 Sc 2 16 .50 17 16 Co 2 27 2 29 25 La 2 32.20 8.90 41.10 23.20 Ce 2 61.40 17.40 78.80 44 Sm 2 5.33 .84 6.17 4.49 Eu 2 1.57 .20 1.76 1.37 Yb 2 1.80 .33 2.13 1.47 Lu 2 0.35 0.03 .36 .35 Hf 2 3 0.60 3.60 2.40 Ba 2 525 65 590 460 Zn 2 116 14.5 131 102 Ta 2 0.44 .10 .54 .34 Table 4-5. Whole-rock geochemical data for basaltic andesites from Old Ungaran. Number of Mean values Si02 58.43 TiO_ .67 A1203 20.16 FeO* 7.24 MgO 1.92 MnO .15 QO 5.15 Na20 2.27 K20 3.11 P205 .31 LOI .59 Total 99.78 Fe203/FeO 1.17 K20/Na20 1.37 Mg-number .37 D.I 53.60 Rb 94 Sr 421 Zr 181 Nb 14 Pb 14 Th 13 Y 42 Cr 4 V 143 Sc 11 Co 26 La 40.50 Ce 74.50 Sm 6.50 Eu 1.77 Yb 3.83 Lu 0.60 Hf 4.40 Ba 629 Zn 100 Ta 0.60 Table 4-6. Whole-rock geochemical data for andesite from Old Ungaran. 350 in l-H > O 1 o CN cd CN p o i' o rT m .e m o o. CO l-H E i' l' VO in l-H ro < oo 00 r- o CN in CM i i ro o r-H in .—i o 00 in (N 00 ON Pu CN CO i-H in 1 I x" 1 c Os r- r- NO CN U Os CN r- rr ro NO 1 i co i si 1 p CN o CO o 00 vO oo in VO s CN CO o o 1 • in CN CO rT oo ro ON 00 in ON CM o CO O o o I CN NO in CO i CN i rT o NO in ON r- ro* 00 o m ON rT oo r- CO ON ro _> o CM rT CN o rT r- CM Cu 1 o i 1 • • rr CN 00 o in CN oo rT T-^ rT rT oo CN rT CO NO in rT CN 8 1 i 1 1 CN 00 o rT in m rT rT o ro 3 00 tN 00 rr. NO CO CN ro O ro CM in r-; i vq 1 p C-; i* 00 rT CO CO Os in r- ro ro r- NOr l-H CM t— Os 00 00 oo r-~ o co rT m r- CM ro CN i i 1 o rT O rT (N CO i 1 • 1 ON in rT —H CN Os ON CN in in ON x> r— CN CO 00 r- 00 VO rT OO CO rr CM 00 NO in in CO in o i 1 i 00 i NO s i t 1 ro ON 00 NO 00 rT rT r- 00 00 rT ON ON ON NO o CO VO 00 CN s oo rT rr 00 in CO o —1 O CN CO CM 1 CO in t I cu • p p CO oo CO NO o r- r- CN rT Os CN oo CN rT o CN Os oo NO rT oo CN 00 s 00 o CM in l-H m o rr CM (N in rT in VO CM :_ 1 NO Os vo ro CN CO CO o o NO CN oo rT rT in in ON rT CO rT CM in ON CO Os CO r- rT rr in o q CO l-H CO co CO CN CM CO rr 1 r- r rT p i 1 i p i i • z O v_ o ON rr 00 00 CNr o ON rT VO 00 ON o ON ON T-H O CO 3 m CN CO 00 l-H l-H vo in in I-H o f-H rT NO 00 rT rT rr 00 1 9 1 1 1 i CO 1 1 u rT 00 ON in oo i-H oo rT CO NO m oo NO in CO o l-H l-H in m rT o O NO I-H NO CM o rH r- CO ^o r- in CN CM rr CO CN o 1—1 o rH CO in l-H m CM i 1 i 1 1 o c • 1 -> , ON in CO _, NO t-~ CN ON ON r_i T-H ON l-H r- 00 ON CN i-H CM r-1 3 ON l-H in o CO ON NO CO in NO 00 rT o rT OO in O in CO m CO rT CN NO CO ro I 1 1 1 1 1 s i i * 1 i _ 1 NO r- rr NO rT CO ON o NO 1 l CO i-H o o o rT m O — 00 ON CN 00 r~ 00 O rT CO 3 r~ o CN o o I-H 3 CN in C^ in NO CO NO CO o in rr rT l-H rr O CO CO NO o r-~ o o 1 i i 1 1 1 I i UH m N" ro vO NO o NO c~ CN NO ON (N IN ro 00 o NO CN CN ON cf? o r- CM NO rf 00 i—i 00 CN CO I—1 00 s CN rT rT NO CO jCN o in CM CO rT r- rr oCN CN CN NO CN CO rT 1 p p p p r-« cs p 1* l" i < ,_, i 1 CO r~ ON in r-~ NO r^ o CO o co o o NO rT o r- CO in NO CN O r» ro rT m —a NO oo rT 00 in CN CN s r~ m co ON CO CN ON m rT in CN m rT 3 rr rr VO (N Number of Mean values SiO_ 49.04 Ti02 1.06 AI2O3 18.52 FeO* 10.06 MgO 4.76 MnO .18 CaO 9.99 Na20 3.12 K20 2.27 P2O5 .29 LOI .71 Total 99.73 Fe203/FeO 1.63 K20/Na20 .73 Mg-number .51 D.I 34.40 Rb 62 Sr 468 Zr 132 Nb 11 Pb 21 Th 14 Y 52 Cr 8 V 231 Sc 10 Co 19 La 28.90 Ce 41.90 Sm 5.47 Eu 1.60 Yb 2.72 Lu 0.44 Hf 2.40 Ba 377 Zn 86 |Ta 0.39 Table 4-8. Whole-rock geochemical data for basaltfrom Parasitic Cones. 352 Number of Average of Standard Range values input values deviation Maximum Minimum Si02 5 53.80 .70 54.47 52.85 Ti02 5 .80 .10 .91 .67 A1203 5 18.70 .48 19.50 18.20 FeO* 5 8.19 .39 8.71 7.86 MgO 5 3.20 .70 4.04 2.60 MnO 5 .18 .04 .25 .15 CaO 5 7.89 .35 8.18 7.48 Na20 5 3.20 .19 3.55 3.06 K20 5 2.60 .37 3.25 2.30 P2O5 5 .35 .12 .50 .25 LOI 5 1.02 .40 1.54 .35 Total 5 99.70 .11 100.18 99.43 Fe203/FeO 5 2.18 1.50 3.85 .80 K20/Na20 5 .80 .11 .99 .70 Mg-number 5 .46 .05 .50 .39 D.I 5 43.96 2.60 47.30 41.20 Rb 5 78 13.20 90 55 Sr 5 606 108.71 739 515 Zr 5 151 14.28 165 135 Nb 5 11 2.30 14 9 Pb 5 16 4.40 22 11 Th 5 10 2.59 14 7 Y 5 27 5.03 36 24 Cr 2 12 5 17 7 V 2 227 8 235 219 Sc 2 20 2.50 23 18 Co 2 29 3 32 26 La 2 29.65 0.45 30.10 29.20 Ce 2 56.85 1.55 58.40 55.30 Sm 2 4.90 0.10 5.00 4.80 Eu 2 1.53 0.05 1.58 1.48 Yb 2 2.24 0.03 2.26 2.21 Lu 2 0.35 0.04 0.39 0.31 Hf 2 3.30 0.30 3.60 3 Ba 2 500 70 570 430 Zn 2 141 41 182 100 Ta 1 0.29 Table 4-9. Chemical data for basaltic andesites from Parasitic Cones. 353 Number of Average of Standard Rang e values input values deviation Maximum Minimum SifJ2 5 56.56 .49 57.32 56.11 TiC_ 5 .67 .05 .73 .60 A1203 5 18.50 .90 20.00 17.69 FeO* 5 6.90 .34 7.14 6.36 MgO 5 2.77 .20 2.93 2.40 MnO 5 .17 .01 .18 .15 CaO 5 6.97 .29 7.35 6.57 Na20 5 3.33 .19 3.59 3.06 K20 5 2.80 .33 3.09 2.26 ! P2O5 5 .26 .02 .28 .22 LOI 5 1.10 .70 1.93 .24 Total 5 99.70 .16 99.96 99.58 Fe203/Fe0 5 1.93 1.02 3.04 1.01 K_0/Na20 5 .80 .07 .90 .74 Mg-number 5 .47 .03 .50 .40 0 2.40 52.10 45.80 D.I 5 49.88 Rb 5 85 10.71 97 72 Sr 5 445 37.46 509 417 Zr 5 156 14.60 175 135 Nb 5 12 3.70 18 9 Pb 5 17 4.80 25 12 Th 5 13 3.92 16 7 Y 5 25 2.01 28 23 Cr 2 7 1.77 8.50 6 V 2 140 15.22 155 125 Sc 2 15 3.5 18 11 Co 2 22 0.25 22 21.50 24.75 6.05 30.80 18.70 LM-AKa 2 Ce 2 54.25 0.45 54.70 53.80 Sm 2 3.92 0.48 4.26 3.58 O __-A 1.24 0.13 1.33 1.15 EJL-tuU 2 Yb 2 2.33 0.12 2.41 2.24 _. U 0.36 0.06 0.40 0.31 __fU 2 In 3.75 0.15 3.90 3.60 H1Xf1 2 30.50 Ba 2 520 550 489 _->u. 11.50 132 109 2—a> 121 7__d.ni 0.77 0.45 Ta 2 0.61 0.16 Table 4-10. Whole-rock geochemical data for andesites from Parasitic 354 rT r-H I—1 o r cd rT CO 00 CmN l-H l" l' X, o 00 r- \JT (_ m VO ro >u rr CN CO E i < O l-H r- rT NO •TH o NO i—i ON C-; ro rT *o 1 i o 1 l' _, > Ha CO CO 00 ^H T-H CN CN X o oi—a oI-H u m CM CO CJ ex i i 1 1 c U CO m r- CN CN t~- rH NO CO ON !+H Cd vo m i-H NO CN o CN CO c i 1 1 o CN CN co NO ^c\ CO ON ri-oH NO o ON u I-H 3 rr CN CO CN CN rT CM tuos 1 i 1 ON CO CN NO ON OO r- o u NO rT CO O rT 3 I-H CO in o CO O m rT 5 4-J i i 1 | I-H NO ON in CO 00 o r- _> « ON CO ON CO oo CN m T-H r- J CU CN o rT CN CN m O tn rr rT VO r-~ CN r— —« I-H CO VO ka m ON ON o CN VO rT Os ON 0 o rT O r- in CO O Number of Average of Standard Range values input values deviation Maximum Minimum Si02 7 50.40 1.10 51.98 48.95 TiO_ 7 .98 .03 1.03 .93 A1203 7 18.30 .65 20.08 18.26 FeO* 7 9.40 .37 9.40 9.87 MgO 7 4.41 .70 5.56 3.40 MnO 7 .18 .02 .20 .13 CaO 7 9.16 .20 9.49 8.86 Na20 7 3.17 .51 3.93 2.50 K20 7 2.16 .55 2.80 1.40 P2O5 7 .40 .10 .60 .26 LOI 7 1.03 .30 1.31 0.84 Total 7 99.58 .15 99.87 99.46 Fe203/FeO 7 2.60 1.90 6.74 1.11 K20/Na20 7 .68 .10 .86 .50 Mg-number 7 .50 .03 .55 .46 D.I 7 38.40 5.04 44.30 31.20 Rb 7 46 17.39 66 13 Sr 7 517 86.51 625 380 Zr 7 151 12.69 165 135 Nb 7 11 1.60 14 9 Pb 7 20 5.70 33 16 Th 7 10 3.29 15 5 Y 7 27 1.97 29 24 Cr 6 22 20.20 62 8 V 6 247 40.50 290 193 Sc 6 27 5 36 22 Co 6 34 3.95 39 29 La 6 32 10.20 51 21 Ce 6 69.37 26.80 97.80 50.30 Sm 6 5.90 1.83 9.40 4.80 Eu 6 1.80 .49 2.61 1.34 Yb 6 2.30 .26 2.59 2.00 Lu 6 0.39 .06 0.47 0.34 Hf 6 3.50 .08 4 3.02 Ba 6 509 79.10 590 412 Zn 4 111.50 56.60 117 99 Ta 5 0.51 .27 0.74 0.34 Table 4-12. Whole-rock geochemical data for basalts from Young Ungaran. 356 Number of Average of Standard Range values input values deviation Maximum Minimum Si02 13 54.67 .86 55.98 53.03 TiO_ 13 .77 .07 .89 .67 A1203 13 19.14 .60 20.36 18.22 FeO* 13 7.78 .50 8.65 6.79 MgO 13 2.94 .39 3.55 2.48 MnO 13 .17 .02 .20 .15 CaO 13 7.45 .88 8.46 5.19 Na20 13 3.17 .30 3.65 2.70 K20 13 2.71 .20 3.15 2.30 P2O5 13 .30 .06 .40 .22 LOI 13 0.88 .50 1.97 0.29 Total 13 99.71 .20 100.35 99.49 Fe203/FeO 13 2.29 1.40 5.37 .96 K20/Na20 13 .90 .10 1.05 .70 Mg-number 13 .45 .04 .50 .40 D.I 13 46.09 2.05 49.60 42.70 Rb 13 68 14.80 91 46 Sr 13 495 69.20 602 366 Zr 13 162 18.55 198 132 Nb 13 13 1.90 15 9 Pb 13 19 3.40 27 15 Th 13 14 4.96 26 6 Y 13 28 2.20 34 25 Cr 3 6 2.89 9 4 V 3 159 37.8 192 118 Sc 3 15 2.84 18 12 Co 3 21 4.36 24 16 La 3 42 8.36 51.30 35 Ce 3 71 4.32 74.70 66.20 Sm 3 5.70 0.42 6.09 5.80 Eu 3 1.60 0.10 1.69 1.49 Yb 3 2.60 0.33 2.96 2.32 Lu 3 0.41 0.07 0.50 0.36 T T C Hf 3 4 0.40 4.50 3.72 Ba 3 608 138 767 520 Zn 3 123 27.10 151 97 Ta 3 0.61 0.16 0.77 0.45 . Whole-rock geochemical data for basaltic andesites from Young Ungaran. 357 Number of Average of Standard Ran cm values input values deviation Maximum 1 /\ Minimum Si02 10 57.19 1.03 58.86 56.00 TiO_ 10 .67 .07 •7 /8 u .56 A1203 10 18.77 .40 19.60 18.29 FeO* 10 6.85 .49 7.61 5.96 MgO 10 2.58 .47 3.24 1.98 10 .17 .01 MnO .19 .15 10 6.60 .70 CaO 7.49 5.39 Na20 10 3.10 .30 3.90 2.76 K20 10 2.78 .17 3.04 2.54 P2O5 10 .30 .05 .40 .22 LOI 10 0.90 .40 1.57 .44 Total 10 99.60 .12 99.74 99.35 Fe203/FeO 10 1.85 1.16 4.88 80 K20/Na20 10 .89 .08 1.01 . 71 8\j Mg-number 10 .45 .04 .49 .40 D.I 10 49.02 3.92 54.10 41.30 Rb 10 84 8.80 104 76 Sr 10 465 46.00 552 399 Zr 10 168 13.40 182 141 Nb 10 14 2.58 17 9 Pb 10 20 2.30 25 17 Th 10 15 4.26 20 5 Y 10 26 1.98 31 24 Cr 7 10 5.32 21 6 V 7 137 41 195 80 Sc 7 12 3.73 18 8 Co 7 22 7.45 31 10 La 7 36.60 5.76 44.60 28.90 Ce 7 65.10 8.25 77.10 52.90 Sm 7 5.20 .40 5.63 4.70 Eu 7 1.40 .07 1.53 1.32 Yb 7 2.50 .11 2.87 2 Lu 7 0.41 .03 0.44 0.37 Hf 7 4 .50 4.81 3.40 Ba 7 574 93.90 684 390 Zn 7 111 28.50 148 71 |Ta 7 0.75 0.16 0.87 0.43 Table 4-14. Whole-rock geochemical data for andesites from Young Ungaran. 358 rT Os > CO o l' CN 00 cd CO l-H o i—i i" p o t-» NO c_ CN r- CO E CN CO p 1* x CO OO VO SO oo ON 3 o CO O I-H CO l" l" i 1 oo CO r- ON CO Ua 00 x' o m CN CO co ex oII NO I oI in CN co co o co M in CO CN rT VO f- cd O r-a CN i—I I-H CO DH i* i* r * r r m co co rr rr o NO CM ON CN -H oo r- o l-H r-H O O O 7-"* CO I i—' CN ON CO ON i—I00I—I O—irHrncNOOOrr rT CN O CO O rT CO rH ""ill I VOOsVOr-HrHONCNOVO _> voinr^incNOvr^OrH DH CO —i ro p I-H I-H CN CN p i • i i CNrtONOtnOrrOvONrr OONI—IONOOI—iNotntn i—"rTrTi—i I-H CS I-H I-H i—lO i" r * * r i' cNOsoot-~—«r~oooNopNO ti inooinONOOi-HcooocNOin vq CM r»- co co CN CN p rr CN p • i" * * i" i* OOi-HOOOr^r-CNNOrrrrvOrr CaO cNOONOoor~-NooNr~ONNOrr I-H CN rT I-H p p p O CS O T-H CO i* r * r i* r • i* oorrr~coooNcoor~NOrrooo CH CS0000ON—it^NO^COOONOOOCO OCNCNCNCO—II-HO—irHCNOin la-l 00 Os NO o in NO m r+ ON -3- ON in rH o 00 i-H r-H VO NO O CO CO Os o o 00 m CN CO in CN O CN CO CO DH CN CN O rr O CN m vo CM vo r-» t-~ -H CS rH HH- O o vo rr r- in I-H ^r in z CM i—I rH O m 00 rT i—i CO CN CO r- —i oo NO rT rr CO 00 ON O CO in 00 in VO ON O CN r~ NO —I ON id" ON oo in CM o m ON o o I-H vo ro CN t-~ r- -so c co CN cs CN o O o o eN CO rT rH O r-H s in o OO NO in NO NO VO CO m ON oo oo co in ON in m ON CN CO ON (N NO VO CO r- NO oo t-~ NO l-H CO CN rH oo o t- O NO CN CN CS CO co m rr CN m o co * 0O t-~ oo o m o oo r- rT rT CN 00 r~ O ON r» ON -^ rT ON rT l-H CM o co rr CN NO 00 CN NO ro CN ON CO i-H CN I-H NO 00 I rT rT 00 I-H o in m ro m CN O m m rr _? 00 in CN Os oo in NO O vo CO O CM CO CN r- CM ON CO NO oo 3 NO O r-H m CN rT CN —< rT o CN O r- CN co CN 00 00 i CO in CN NO o O CO CN 3CN m Os 00 in N- NO r~ r» rT CN m Number of Average of Standard Ranpr values input values deviation Maximum Minimum Si02 57 54.00 2.90 60.80 48.95 •no. 57 .81 .10 1.08 56 A1203 57 18.97 .65 20.80 17.69 FeO* 57 7.75 1.1 10.32 5.96 MgO 57 3.25 .80 5.56 1.57 MnO 57 .13 .02 .25 • 1_. 3+J CaO 57 7.79 1.20 9.99 5.14 Na20 57 3.08 .38 3.93 2.12 K20 57 2.58 .38 3.25 1.40 P2O5 57 .30 .08 .60 .22 LOI 57 1.23 .40 2.30 .24 Total 57 99.65 .15 100.35 99.34 Fe203/FeO 57 1.97 1.23 6.74 .80 Mg-number 57 .46 .04 .55 .36 K20/Na20 57 .90 .15 1.37 .49 D.I 57 44.45 5.95 58.70 29.90 Rb 57 69 17.57 104 13 Sr 57 494 73.38 678 366 Zr 57 151 21.91 198 104 Nb 57 12 2.40 18 6 Pb 57 19 4.41 33 10 Th 57 12 4.60 26 2 Y 57 28 4.96 52 22 Cr 30 13 11.5 62 4 V 30 194 66.8 290 116 Sc 30 18 6.67 36 8 Co 30 28 7.52 40 10 La 30 34.07 8.89 51.30 17.90 Ce 30 64.20 16.20 51.3 37.8 Sm 30 5.46 1.11 9.40 - 3.58 Eu 30 1.60 0.31 2.61 1.15 Yb 30 2.44 0.41 3.83 1.47 Lu 30 0.40 0.06 0.31 0.60 Hf 30 3.55 5.41 4.81 2.40 Ba 30 541 119.36 767 367 Zn 28 117 28.20 185 71 |Ta 28 .58 .19 .87 .24 Table 4-16. Whole-rock geochemical data for all rocks from Ungaran. 360 Number of Average of Standard Range values input values deviation Maximum Minimum 50.60 1.04 51.98 48.95 Si02 18 Ti0_ 18 .97 .07 1.08 .80 19.07 .70 20.80 18.26 A1203 18 FeO* 18 9.45 .39 10.32 8.61 MgO 18 4.15 .60 5.56 2.98 MnO 18 .18 .02 .20 .13 CaO 18 9.01 .50 9.99 7.60 Na 0 18 2 2.98 .50 3.93 2.12 K 0 18 2 2.27 .40 2.80 1.40 P2O5 18 .36 .09 .60 .26 LOI 18 Total 18 0.96 .24 1.93 .98 99.57 .13 99.76 99.34 Fe203/FeO 18 1.86 1.35 6.74 .96 K20/Na20 18 .77 .17 1.02 .49 Mg-number 18 .49 .04 .55 .40 D.I 18 38.60 4.80 47 29.90 Rb 18 57 16.30 81 13 Sr 18 506 79.06 678 380 Zr 18 141 18.38 165 105 Nb 18 11 1.50 14 8 5.90 33 10 Pb 18 18 Th 18 3.30 15 2 Y 18 10 6.40 52 24 Cr 12 29 15.10 62 7 V 12 17 31.30 290 193 Sc 12 248 6.39 36 10 Co 12 23 5.67 40 19 La 12 33 10.30 51 17.90 Ce 12 32.20 23.20 97.8 37.80 Sm 12 1.43 9.40 4.43 Eu 12 63.83 .39 2.61 1.34 Yb 12 5.92 .28 2.85 2 Lu 12 1.79 .05 .47 .32 Hf 12 2.41 0.78 4.00 2.40 Ba 12 .39 78.40 598 377 Zn 10 3.15 53.50 185 86 Ta 10 505.80 .26 .78 .24 K/Rb 18 119.64 140.41 894 209 Table 4-17. Whole-rock geochemica.50 l data for basalts from Ungaran. 363 361 Number of Average of Standard Ranee values input values deviation Maximum Minimum Si02 22 54.20 .91 55.98 52.85 Ti02 22 .78 .07 .91 .67 Al203 22 19.04 .56 20.36 18.20 FeO* 22 7.97 .43 8.85 6.80 MgO 22 3.06 .50 4.04 2.48 MnO 22 .18 .02 .25 .15 CaO 22 7.74 .80 8.56 5.19 Na20 22 3.10 .30 3.65 2.39 K20 22 2.66 .24 3.25 2.30 P2O5 22 .30 .07 .50 .22 LOI 22 0.87 .50 1.97 .58 Total 22 99.65 .17 100.30 99.40 Fe203/FeO 22 2.15 1.28 5.37 .80 K20/Na20 22 .86 .10 1.05 .70 Mg-number 22 .46 .04 .50 .39 D.I 22 44.90 2.85 49.60 38.10 Rb 22 66 12.96 91 44 Sr 22 516 76.61 645 366 Zr 22 148 24.55 198 104 Nb 22 12 2.60 16 6 Pb 22 18 3,60 27 13 Th 22 11 5.10 26 2 Y 22 28 3.36 35 22 Cr 7 12 11.30 36 4 V 7 191 39.10 235 118 Sc 7 17 3.37 23 12 Co 7 25 5.03 32 16 La 7 35.69 9.31 51.30 23.20 Ce 7 64.20 12.30 78.80 44 Sm 7 5.37 .66 6.17 4.49 Eu 7 1.57 .13 1.76 1.37 Yb 7 2.26 .44 1.47 2.96 Lu 7 .38 .06 .50 .31 Hf 7 .53 .67 2.40 4.50 Ba 7 553 110 767 430 Zn 7 126.10 31.40 182 97 Ta 6 .50 .23 .77 .29 K/Rb 22 344 69.89 501 267 Table 4-18. Whole-rock geochemical data for basaltic andesites from Ungaran. 362 Number of Average of Standard Range values input values deviation Maximum Minimum Si02 17 57.29 1.30 60.80 56.00 Tif>2 17 .70 .06 .78 .56 A1203 17 18.80 .66 20.16 17.69 FeO* 17 6.50 .40 7.61 5.96 MgO 17 2.54 .48 3.24 1.57 MnO 17 .17 .01 .19 .15 CaO 17 6.50 .78 7.49 5.14 Na20 17 3.13 .37 3.90 2.27 K20 17 2.80 .23 3.11 2.26 , P2O5 17 .29 .04 .40 .22 LOI 17 1.27 .50 2.30 .48 Total 17 99.70 .10 99.74 99.35 Fe203/FeO 17 1.90 1.02 4.88 .80 K20/Na20 17 .91 .15 1.37 .74 Mg-number 17 .45 .04 .50 .36 D.I 17 50.10 4.03 58.70 41.30 Rb 17 86 9.90 104 72 Sr 17 453 42.88 552 399 Zr 17 165 14.18 182 135 Nb 17 13 2.80 18 9 Pb 17 19 3.58 25 12 Th 17 14 3.90 20 5 Y 17 28 5.06 42 23 Cr 11 9 4.66 21 4 V 11 136 49.40 195 116 Sc 11 12 3.53 18 8 Co 11 24 7.77 39 10 La 11 35.04 7.40 41.80 18.70 Ce 11 63.16 8.80 77.10 52.90 Sm 11 5.03 .77 6.50 3.58 Eu 11 1.42 .16 1.77 1.15 Yb 11 2.60 .48 3.83 2 Lu 11 .42 .07 .60 .31 Hf 11 4.00 .43 4.81 3.40 Ba 11 572 170 684 390 Zn 11 109 25.60 148 71 Ta 11 .71 .16 .87 .43 K/Rb 17 274 27.89 336 215 Table 4-19. Whole-rock geochemical data for andesites from Ungaran. 363 in ON O l* ON l-H CN • 1 X NO 00 p. i-H CN E rT rH o CO < 1 CO 00 o x ON CS ON 00 o CN tu CN o o in o x' co —; ON r- CN a p vo CM —i o i" i" U in t-- ON oo r~ oc M r~- NO co o os NO CO CS —; r-< O CI rt i" i" r i* p vo o vo r- o x r- in in o —> ^j- oo —; —; C> —j —> —< ! .... CSVOVOCOOONOOCO ONCOCSinrTCOONON X ~. ~; fi « (sj ^ ^ p i* i* I* DH Sooco—Hor~r~inin co—iNOrooorrinrr CN) q n; —: cs <~> ro o p II r~-ONinrroinincoinin SONCSCNCOCOONOOOSO ti rf—;—;—JO—"CNCN'CN i* i* * • r i' N;rf;eocsrr — ocor^inos CO CNrTvOO—'rTOOrTOOr-CS c"~:cir~:'-; —;copcococoi-< i' i* * i" r X OI-HOOI— 60 x ___ O CN W o o 9. X « Oa Ua 3 I •"5 *- ti [5 x W > g P 3 kC Di CO Cu I s s s _s 5 O 364 K Rb Sr References ppm ppm ppm Basalt 18829 57 506 1 Basaltic andesite 22115 66 516 1 Andesite 23360 86 453 1 Basalt high-K calkalkaline 19757 66 711 2 Andesite high-K calkalkaline 27478 87 949 3 Oceanic floor basalt 1160 1.1 136 4 Andesite calkalkaline 12900 30 385 5 Island arc tholeiite 5000 5 200 5 Table 4-21. Trace element data for several volcanic rock suites. Also see Figure 4-28. 1 = present study; 2 = MacKenzie and Chapell (1972); 3 = Ewart (1982); 4 = Hart et al. (1970); 5 = Jakes and White (1972). (a) (b) (c) SiCo. -.169 .601 .444 Al203 .021 .430 -.795 MgO .176 -.602 .319 FeO .156 -.477 -.681 CaO .090 -.704 .194 Na20 .163 -.053 .752 K20 -.210 .166 .102 TiC_ .178 .608 -.127 Rb -.212 -.098 .672 Sr -.353 -.459 -.436 Rb/Sr -.102 .091 .460 CL. .423 .553 .623 Table 4-22. Con-elation eoeffieien, for Sr isotopie, major and traee element dam for Ungaran voleanie roeks. (a) - all samples; (b) = sample < 53% Si02; (e) = sample > 53% SO* CL. • limit for 95% confidence level. 365 *nrT 3 cd _5 _ ' V A r^P O •<— I 00 j_ »o j_s cd tO T_ o i © tOfc •i—( S bb JH«0 ?^ CO c>o ^—'tO bO\E Xi ^H bb > ba © *^^ S G C oo © K t> cs cd ^ •** JS •O « c © feb_ o FT u •»in OcOtO "8 CH ^ CN c .- *—• .a - 13 tO _»« © . 0 c«j_3 cd vo I O W «©* bX) -"^ o V 5G M cs bX) § -fl O 4- © s^ •31 <*H *-• 00 _ & a> o © cs "55 ' Number of Average of Standard ~ Range values input values deviation Maximum Minimum 1.80 54.47 48.95 Si02 20 51.34 TiO_ 20 .93 .11 1.08 .67 .70 20.80 18.22 A1203 20 18.93 FeO* 20 9.13 .75 10.32 7.38 MgO 20 3.91 .70 5.56 2.67 MnO 20 .18 .02 .20 .13 CaO 20 8.76 .68 9.99 7.48 3.93 2.12 Na20 20 2.96 .50 .38 3.25 1.87 K20 20 2.50 P2O5 20 .36 .09 .60 .26 LOI 20 0.85 .28 1.64 .58 Total 20 99.60 .10 99.78 99.34 Fe203/FeO 20 1.87 1.06 5.11 .96 1.03 K20/Na20 20 .80 .15 .50 Mg-number 20 .48 .04 .55 .40 D.I 20 41.20 4.96 47.50 29.90 Rb 20 64 13.30 86 40 Sr 20 520 75.26 678 415 Zr 20 141 21.04 175 104 Nb 20 11 2.05 15 6 Pb 20 18 4.35 31 13 Th 20 10 4.11 17 2 Y 20 30 6.18 52 24 Cr 9 18 17.20 62 7 V 9 255 33.20 290 193 Sc 9 23 7.48 36 10 Co 9 33 6.44 40 19 La 9 32.70 11.80 51 17.90 Ce 9 68.40 26 113 37.80 Sm 9 6.15 1.51 9.40 4.63 Eu 9 1.88 .40 2.61 1.48 Yb 9 2.46 .29 2.85 2 Lu 9 .40 .06 .47 .32 Hf 9 3.18 .54 4 2.40 Ba 9 502 79.50 598 377 Zn 8 105 60.9 185 86 Ta 7 .48 .26 .74 .24 Table 5-2. Whole-rock geochemical data for shoshonitic rocks from Ungaran. 367 Number of Average of Standard Range values input values deviation Maximum Minimum Si02 37 55.40 2.20 60.80 50.88 Ti02 37 .30 .11 1.03 .56 AI2O3 37 18.99 .60 20.36 17.69 FeO* 37 7.55 .80 9.40 5.96 MgO 37 2.89 .60 4.44 1.57 MnO 37 .17 .02 .25 .15 CaO 37 7.26 1.09 9.19 5.14 Na20 37 3.03 .34 3.90 2.27 K20 37 2.60 .38 3.15 1.40 P2O5 37 .31 .06 .50 .22 LOI 37 1.31 .47 2.30 .48 Total 37 99.66 .16 100.35 99.35 Fe203/FeO 37 2.02 1.30 6.74 .80 K20/Na20 37 .86 .16 1.37 .49 Mg-number 37 .45 .04 .50 .36 D.I 37 46.20 5.75 58.70 31.20 Rb 37 72 18.79 104 13 Sr 37 480 69.40 645 366 Zr 37 156 20.90 198 112 Nb 37 12 2.57 18 8 Pb 37 19 4.49 33 10 Th 37 12 4.70 26 5 Y 37 27 4.06 41 22 Cr 21 10 7.40 36 4 V 21 171 57.7 240 116 Sc 21 15 4.88 24 8 Co 21 25 6.61 39 10 La 21 34.63 7.59 51.30 18.70 Ce 21 62.38 9.88 78.80 44 Sm 21 5.17 .75 6.50 3.58 Eu 21 1.49 .17 1.84 1.15 Yb 21 2.43 .46 3.83 1.47 Lu 21 .39 .06 .60 .31 Hf 21 3.74 1.41 4.81 2.40 Ba 21 553 139 767 390 Zn 21 116 26.60 182 72 Ta 20 .62 .23 .87 .29 Table 5-3. Whole-rock geochemical data for high-K calcalkaline rocks from Ungaran. 3 68 o CA >oo\ in m^ooMfi CA r^ H CO I-H O rT /loqvivi^riHmoO'Hinin ON to ON f- rH CS VO to - i-H 00 rH tO rH —4 O CO l-H VO 00 cs «0 rT oo rr cs CO J3 cs >o cs r» rH rr co r^ cs 8. a i-H CO rH rH NO CNrTcOrrOCStOior^^HOOON co to CO II i^r^i-Hcsr^r-<\ovoTrocO'-H vq —J I-H CO C-; |B O rH HOcdcNi'ctd'oocitNiMdH oo rr r- 00 00 o r- CO •<$ O CS* CN CS* O to VO CO _ II 82? lO —< CO ON lO cs cs cs t-» CO VO CO —* CN 00 i-i r- •In. O vo O co oo O O to co oo rn ON CS o "* S I -s oq —< NO —0 r^ c~- 4J ON O E ON —< to CN vd O 00 ON CS* CS* O* CS cs o n N" r-i cs to o *~*_ —j 1-1 r* O r- O ON to CO CS TT CO —i r- co to co oo II• O ON CO r-H O l-H —| oq so cs oo r^ co to p co p O I-H 00 t-- r~ co to vo OS ON r- rf _. IO ^H O NO ON CO Ci O O 00 —< —i 00 r-H ON to CS OS cs' CN O rr' N" CO cs rH -3- CS CS r-i 00 r-H r- cs NO i-H oo ScU- _ S WON o co o -H NO NO cs cs r- o o N;ON.^riooNi-HONcooNoot~-to ^s«-ra ONOCOr-ilOOOOOr-HCSOCO o o vo r~ CS CO CO vo O o < CO IO CO ON NO rr •— —, • 1—1 «o o cs o oo to vo oo IO r~ co to ^r^P^l ON ON o ON NO ON I-H O r- O rt co co cs CS rt; CN —< ctOr-;rrT-H00lOrr-Hs c 25 ON y a < O 00 tO CO O rj- OS CO CN O H O CO i—i •-< 00 o o o oo to co oi od vd i-i CN" © coco vq to to VO -H rT -H r-. r-H CO 00 CO O ©' 6 tO i—i —I to CO CO vo cs IO cs cs t&t "1- —I CO CO _ • & _ _i" cs cs o O C~> £"} o _ to rr &s-i. ?H—! 4> OiS TH " _? CS ° Fs p Ctn oo N 1 >o_|-a H •< & £ S S CJ £ « CNO ££»5 B&>daQ&&£3}Si*&&aia X> "O O 3 I CH _1 369 c OO COOOVOVOCOOO to r— o ON CO O NO 00 CO - —. —i CS CO VO r-H ON 00 r^ NO CS ^H I-H r-; I-H cs rr >o co I-H W-, to !• -E _| ..:(f)H> rH NO O rf NO CS* CS* O CO O —i o VO -* ON to r- to CS* rf IO •-" cs' ©' CO CS cs o ON CS CS CO cs t-- o CS r> Cj . - . IO -H cs o brt^-N >-i -J E rT «> rn ^ l~- __ r< {Scrico'*ONCStorroooN ooto <-> ON "O ll i> ^ Oi q ri- I-H oq oq rr «o cs ON <13 il£ eN O NO CS* rf NO 00 CS CO O O •—< ON f- o O O —< cs I-H f- CS .— 'G >-v —i JcO) co^-r-oovotoi-Hr^ootOT-H to r~ cs vo w sMOK-lNNHTHTtvqitr-O r— NO NO rf to « E oo rfrHVOrfcOOcOlOCO rf O CS 00 O o VOI-HCSCS0000I-IONONVOI—iCSOrfrf rH 00 ! ' H^-* .rH i-HVOOOOOOCStOOOrrcS IO tq io tq to to H H o\ > q q q t-; r>; ov oo cs oq co to vd oo" od ooON CO coor^rfcsoco'oo'cs'csocs CO 00 00 CO CS rH r- : IO —I CS —I CS ^tooototooooocso | § 00 O rf 00 VO IO o ON CS ON 00 CS CO 00 ON rH IO NO rT to CS rf CO O rH <_i CO CS O IO O rf 0O rf rH CO ON rf rT to r~ CS 00 CO (-• ON O CO O to t-» VO CO -H cs IO ON oq cs r^ cq CN to CN r- p rr —; oq p ON r-; I-H vq d ON CS CS CS r-i rf >0 if rf VO CO CS © —i O I-H" O O O O 00 O CO ON •-* I-H O CO CO ON tO rn CS rf io cs CS CS rTNOOOCSCOCOONrHVOCSiTtO r»- I-H r-- cq cs# —j co oq rr cq vq r-- -HrHvdcotoovdodcscNOO IO T-H O ON oo O ON O NO cs ON O NO CS NO rf 00 to to CN CO CO CO O CO 00 CS o co cs oo r- 00 00 —i cs to —1 ~ co r» vo co CN CO rT ON SO rT cs cs ON ON rT -H Nq CO vO rf O CO r-n' —i CN —> CO CS ONOotor-Hvoooootor-HNor-co VO NO NO vq ^ cs; u; q m rn N q CM rr cs oq T-HVOCSOOVOCOOt-~OOiT rr r~" od odTH'iocovdor~*ONCs"i-HOco NOQCS 1-HrtCOrHCOCO rr r-1 o o CS O 00 00 ON ON 00 ON it C-; CO O I-H r~ ON I-H rr a ON O NO ON O rf if CO I-H If -H cscooovocovooNtocor-Oi r» co VO IO I-H ON IO 0O CS t-H vq cs tq r-; ON I-H cs_ to cs cs cq ON r^' r~* CO to ©' NO O CO I-H o 00 vo vo r-ooi-ir-rHOrroo rf I-H I-H CO -H IO riOOCOVO-HCOCNrf vO co torr r-csooNOrrr-oocsoo ON ON OS ON NO CO NO ON O I-H iq rf rf I-H vo 00 ON rT CO ON OO CS rHor-r~-r-~ONvorH CS w —i —iodcotodtoodcor-id cs rT O NO IO rH COCOtONOOOCSrnrf VO i-H itr-csooNi-~vovovoior-« o IO CN to to to r- CS ON 00 I-H p rH cq ON CS CO tq NO vo cs vo o r-» VO NO 0O OMH ON ON CO CO o\ H vi it r~ d r* oo m H d co t~- vo CO cor-ooNcocor~rH rr —i r- r-H rH rH CS CS ocoNO"ccrcsior~-ONCStooo 00 ONt—rror-r-Hcor-irrrrto I-H CS vq NO —j IO ON NOrflOOt^ONCOrHO CO rf NO 00 rf i-HooooNotoodrrov u N- CO 0oo0 cOs rH i—( cotorrr-csrrr^ON rH cs cs rfcsoor~csNor~otooooNOi ONONrHt^COrHONOOONCOlOO CQ -H O NO CO rfOVOOOCNCSO—i VO —I t— IO i-H NO —I 00 t— OvOrTOOiOOOOto—icSrTto NO >o oo CO NO NO tq cq rf rr 00 ON r-< ON CSI ^H CS NO 00 NO CO I-H Hr^t^t^qqqqcorH vq ON CO to rn co o cs' d t-i rf o'o'o'vdes'o'rfodcs'^HO-H' cs" od d d to to i-i cs' d co od cs" od d rr r- rr —< cs cs rH cs co co to «o cs o cs I-H rf rH cs IO i—i CO CO NNOO o o co CN r- ON NO O io t~- rf A8 O, oo vq "t Ov NO o ON t> |MM CO O CN r- CO H IO (S» t^ rH >o „ B r~T-HoovorHOOONr~r~-vo Oi •a -" tq (-; rT ON rT r-H CS p NO NO H0 0 s e3 J oi d rf cs' —I d cs i-" co cs' d rf 00 ON OO to r- i IO I-H CO vo r-1 CO SS £ II •a CO rH BBK cu -, ._. NOcOt^rfrTCOCSNOONOO to ON 5 in H, NO t-; C-; rT 00 r-H Os 00 tq r~; rfC O *—i r-" d od rf r-i d co rf cs' cs d1— 1 00 CO i—1 -! IO rH CO © rH •it l-H — on o u a> o —'f-CSCS VO ON r~- OO © CO C- VO r-. r-; —^ os >q> t^ CJ0_2|f, i *~~i CO © I-* CO r-i rf CO CN r- cs NO vo © r~ r-©toNOi-icN; cq r-^ vq cod cq NO rH o r~ cs --> CS i—i rT 00 ^2'gfEn » i—i to cs CO I-H 8II c9 8 >< COCOOrfONONrTrftOCSi—i ON 8< w co S rT ON p ^H ON p p 0O © ON cq ON •a H-« NO d NO cs' CO © NO to rf —i d d © o r- © I-H o oo Q'S . VO i—i oo o NO VO I-I oo I-H l-H a c•_s- o —• to CS •JG 00 OtOO©©tOOO©©r-l o T-H .2 fl2 C/ l rT rT —; O •-< p NO C-; rf CS CO X -Hdr-~cocodcs'tococsd d to r- o CO VO IO I-H 00 O NO r^ NO NO O CS IO CS NO E •Q VO rH HIo CO J= < CO O CSitPOr^OCOCOCOrrrf-H ON •S •a rT NO_ rr r^ IO I-H I-H tq ON oq CN ON NO 3 .£?&_>3 ll 1—1 oi d vd cs' co d co vd cs' cs' d O ON ON CO -H 4-> NH" o IO i—i rf IO I-H l-H 8 _ > cs .. otococor~-cscocsvocorr r- vo cn I-H p vq -• 2. ° PH tO C-; CO H ON I-H T-H r~ CO C-; cs it r- oo d rf C-;iqrr NO tq --^ H rT ON © I""" CO CN © CO VO CO CS' O oddootoodrH'cs cs to IO -—I VO O IO r-1 rf rH CO CS rf CS I-H CS rf -•5S_r l-H Oitor-i-H©cstor-tor— •—i rf o w g- rf w oq ON © cq © I-H cs NO ON rr cq rr vq ON r-^ oq ON O 4) f3 T3 ONdr-^cocodcoiococsd to oo to rfoodoitodoovd i-i >o •—i CSrfcor-rfCSCONO g^ici ^32 I-H •§ " S s CScOrfOi—ii-HOOCStOi—icS oo oq cq oq c-; p oq oq r-; r-< r-- cq ON co rr CS ON l-H NO Sua* Q vd ON r- r-^ cs Oi'—ivdcocsdcs'tococo© cs' r- to cs rr —i o if cs oo rr r-» rn cs o cs «> ""-' tO —i rHCONO©COCS©r~ Oi cs 1—1 I—I l-H T-H s^« §• ONOooocscocsr-rHiooto S.CS o 00 —< vq cs NO •O-'ftrH rr ON ON co cs T-H cs p vq vq co tq rT CS CS_ CO rf U ON©NOcocodcovdcocs'd ON OO CS vd rf Oi © CN 00 rf CS ofg^2 IO I—I r- —< cs •-1 cs CS rf rf C- rH "o rH CS JG Umui c tOONONCOONOONCOOOVOON rf I—1 cs "g S " & © ON I-H ON to I-H vq 0O rf © VO cq CQ VO © OO CS rf © cs' VO CO cs' d ON ON od VO i-H IO r— cs gB WH-8 r- O US— 8 ON f- r"-rfCSr-~rfrfcO-HON .-. °o cs _"« covqr-~tqcqi-Hio»orHoocs _^,tQ CO CO CO rf rH CO _^ II < T-H r-" © od rf cs" © cs' vd co" cs" d —; ON co p oq ON rtrfcoorrr^rrotorH 0.7 3 o .S 2 TJ r-1 to —^ rS ivJ K5 ^ °* "* _TC 00 ^H rn' io' CO IO -i cs' © rf od111. 1 -i U 3 ° E . . OO IT) IO rH rH rH M CO N CO Ifl CO H .CD CO « O It I-I rH |/-J ii 3g h—1 °? > -J I, uP* ,9> Zc^rB VO co H < PH fcSSUrH fc-t _T 3 «WNZPH [5>,C.ga>056lt-r2>3rS(-?CO «S0 >,o |o| oo J? oo __ " ON JON 373 921 918 832 826 823 917 SiO_ 49.39 51.92 49.73 50.12 51.47 49.04 TiC_ 1.08 0.97 1.06 0.98 0.87 1.06 AI2O3 19.25 19.88 20.80 19.27 19.22 18.52 Fe203 2.06 1.88 1.89 1.92 1.82 2.01 FeO 8.25 7.55 7.57 7.69 7.26 8.05 MnO 0.20 0.19 0.18 0.20 0.17 0.18 MgO 4.59 2.98 3.30 4.07 4.10 4.76 CaO 9.59 7.63 9.08 9.11 8.73 9.99 Na20 2.12 3.15 2.98 2.97 3.32 3.12 K20 2.02 2.79 2.06 2.22 1.64 2.27 P2O5 0.34 0.39 0.35 0.40 0.35 0.29 Mg-number 0.50 0.41 0.44 0.49 0.50 0.51 824 833 326 438 417 418 S-O2 50.91 50.88 48.95 51.04 51.98 50.00 Ti02 0.95 1.03 0.99 0.97 1.00 0.96 AI2O3 18.54 20.08 18.34 19.12 18.26 18.42 Fe203 1.84 1.84 1.95 1.88 1.78 1.88 FeO 7.36 7.37 7.78 7.52 7.14 7.51 MgO 4.50 4.07 5.03 4.44 3.43 3.83 MnO 0.18 0.19 0.18 0.18 0.13 0.18 CaO 8.96 9.03 9.49 9.19 8.86 9.19 Na20 3.07 2.51 3.60 2.60 3.20 3.93 K20 2.57 1.40 1.87 1.83 2.76 2.83 P2O5 0.28 0.29 0.60 0.39 0.26 0.46 Mg-number 0.52 0.50 0.54 0.51 0.46 0.48 Table 6-1. Major element compositions of the most mafic rocks from Ungaran. 374 CO CN CN to ,_ _ rr (N I-H NO CN o ^_, CN oo CO to rT rT 1—1 r^ rr P-; CN lO rT X) r>* d rT* r-H ON* rf d r-' CN* T-H d vd r-" cd rT T-H T-H CN i-r-H ON oo Os r-H 00 T—H NO to NO i—i o rt O rT l> oo IO NO CO IO l—< CO NO ON CN to OO cd r-* d to' r—t ON d od CN* d oo' NO* 1—1 I-H rr - oo ON CO CO o oo CO r- _ ON r- o NO CO NO i-H rr OO cq I-H oo NO CN CN p o X> ON o to T—1 OO CO O NO CN T-H O to d rT I—1 r-H CN i-H CO CN OO o CO CO rT NO CO rr r- O oo o o ON o r- CN to 00 oo T-H CO oo r- CO CO cd T-H p o o VO 00 o o r- CN T-H o od ON >o I-H 1—1 l-H vo to CO r- CO r- to VO t~» o o o VO O CO CN I-H ON CN CO VO JD r-~ r- rr r-; p 00 d rT* ~ ON rT* d vd CN* I—H d od r-* rT T-H i-H CN vo CN OO r> r-H to Os CN CN r- rT NO rT CO O r~ NO OO ON to CN rT i—i to rt CO ed oq o p od d to T-H o* d r-* CN* T-H d d r-* j rT CN ,_ oo rT ON CN CO o o CN NO O to ( 3. CO CO NO T-H to CN IO to ._i r- oo r^ CN r-" d to' ~ ON* rf d NO CN ~ d i-H OO* rT T-H CO CN CO OO o WO CN T-H CO ON to to OO to 00 o o to IO i-H CN CO NO CN to ON cd p oo so d NO ON T-H d r-* CN T-H CO* r-* od d CN rT CO o CO to ON ON rr o r- 00 o vO JO r-^ t> CO CO CO OO f—H IO CN o cs to rT od d rT* I-H ON rf d to CN CN d CO VO* rt f-H T-H CO oI—o1 ON x/i s*—^ O vo CN r> CN ON •o to VO OO o o t->. to rT T-H ON r-H CO to ON o & rT r» r-- O rT •rH T—1 -*—» cd d to ON CN* d wo* CN CN d to to 4— o" T-H in CN O v£—' rT CH T<3U B > o CN to NO CO , CJ t-~ vo o rT NO o NO h s-z^ to OO NO to OO T-H NO to _ X) r- cq CN to rT 4— S rT I-H ON* r-H l-H ^ r-* d rf d r-* d CO od rH T-H T-H i-H rT CN o cu CN B C ON d C • i—< •d VO ON VO i—i o NO VO VO o to NO oo o i-H a > OO OO NO O r-H ON NO CN to oq b UH u cd p l-H t+H to ON CN* d r-* T-H /—\ a d T-H d d r-* od T-H .0 o UH CN 5 rt T3 4H O CN* o 1 § CO CO VO cs O o o o >o cU "oo cd X) 6" o O X3 00 3 o rt O _ t— CO rf CO CN VO rj d> <±> v6 to <_> CN oq O rt CN © T-H r-H CO O r^ T-H p p p X> i> d rf ON rf t> CO CN* © od NO rt T-H l-H d CN NO oo VO CN © © © to r-H o O to x> to r» ON cq © l> T-H t> rt i-H CN I-H ON CO* I-H ON co NO CN CN* pod rt d T-H T-H d d CN d CN T-H rT l-H CN NO NO ON ON T-H i—t rT oo T-H © T-H CN OO © rT OO ON i-H CO VO CN CN to r-- cd © © IO T-H OO © © r-~ CN CN* © to to T-H T-H CdN NO vo CO OO rr oo rt CN rT T-H © rt ON r-~ rT ON vq T-H CN © 5 CO © O X> od d tpo T-H od CO* d tZ cs r-H d to* ON rr I-H i-H CN OO CO rT l-H CN ON ON r-H VO to OO © to CO O ON NO OO I-H IO OO ON l-H r- CN IO CO to CO cd ON © NO T-H oo © o r- CN o oo rt T-H T-H T-H ON VO ON VO CO CO rt © OO © oo o oo to [-- NO to © r-- T-H vq oo to rt to vq X) r-" © rf T-H ON CO © i> CN* I-H © CO od T-H T-H CN vO rt CN CO CO CN CO oo © CN o ON r-H T-H CN © vo I-H OO oo NO ON © l-H T-H T-H vq to O p ed od IO* T-H od © oo" CO* T-H o oo" d T-H o* rT T-H T-H in GO CO © © rt NO r- to NO so ON CO © oo 'rH I-H •— ON oo C-; rt ON vq oq ON © CN oq 'rH o in X) 00 © to T-H od CO* ©' r-' i-H T-H SO T-H d T-H O rt T-H T-H CN OH CO CO OB , oo c> S~*s- t> CN lO CO to NO T-H r-H l> rT © 4— ^ r^ I-H i-H T-H o »o oo ON to oo ON NO CN tq r! ed T-H T-H pT-H ON d NO od © © r«" CN* d od s £ i-H T-H T-H rt cU d T3 CU o NO ON r- CN to rt NO »o IO CN o rt o O © r- r- rr t^ CN T-H O rt © CN tq CO '5? X) H rO T-H C-* CN* CN* © r? i? ON d rf od CO* d co" vd t*U T) IPH rt r-H i-H CN G CU bn rr cd G G A B C D Si02 49.7 49.1 50.3 -51.2 47.3 Ti02 0.72 0.62 2.8 - 3.1 1.0 - 14.4 15.0 A103 16.4 16.5 12.8 FeO 7.89 8.78 10.5 - 12.4 10.9 MgO 10.01 10.3 6.7 - 9.5 11.6 MnO 0.12 0.15 - 0.2 CaO 13.00 12.4 10.0 - 10.9 10.1 Na20 1.98 1.92 2.2 - 2.5 2.5 K20 0.01 0.07 0.55 - 0.67 1.4 P205 0.06 Mg-number 0.74 0.72 0.56 - 0.66 0.69 Fo (calc.) 89.4 88.6 72 -79 88.0 Table 6-3. Primary magma compositions from several data sources. A = most 'primitive' ocean-floor basaltic glass, DSDP leg 3 (Frey et al., 1974) B = 'primitive' ocean floor basaltic glass from FAMOUS area (Langmuir et al., 1977) C = range of liquid compositions from experimental work of Roeder and Emslie (1970). D = primary magma composition for Ungaran lavas as proposed by Nicholls and Whitford (1976) Fo (calc.) = the calculated forsterite content of olivine in the associated rocks. 377 CN rf CO CN ON c±> N_ 00 ON CO CO © ON T-H in OO 00 CO NO rt ON »q 00 © CO iq CO xx•«—» cd x> ON* d rf l-H NO ON ©* T-H CN* CN* © to' vd X rt r-H i-H CO £ G 00 B O T-H 3 cd rt ON © r- rt •O © r^ rr rt CO NO 0 CO X"C 3 O 00 CO NO r- rt T-H © T-H CN CO © 00 •rH O ed © © to T—1 sd od © I-H CO CN* d vd to •rH ~1 I—I -J O to CN rrU cu W) X4 4 r-H CN C i> VO 0 CO CO rr 00 0 O • I-H c rT ON ON X> 00 CO iq CN tq I-H CO CO 0 I-H © rt Tl T-H T-H I-H CU rf NO ON' © CN* CN © to 3 C/> d I-H vd sin »o i-H CO in CN 3 r-H cd c/i rt T3 C T-H ON CN vq rT © T-H 00 10 I-H CN © ON •a ed l-H © to* r-H NO OO © CN* CN* © vd to 3 • rH IO i-H d O O r-H CN O OH in OB T-H to ON NO CN NO CO r- to ON © to cd OCU I-H NO OO © S to O rT ON cq CN © 0 cd CcU .O O © to T-H NO © T-H I-H i-H © CO* ON* •—' X IO i-H dT-H T-H CO 00 CO I 1 rt OO ON rt r-H to to r- 0 to 0O CN 0 VO G DH i—1 T-H c OO 00 CN 00 rt 00 rt CO © l> 0JQ .—* ed r^ D 0 © d NO* '"H vd 00 © © CN* T-H © CO* OO VH 0 T-H CU to CN <+OH cd {2 B _ T-H VO ON r» r- © © r^ CN rT 10 © CN c IS CN 00 VO 00 CO I-H 0 CO rt © CO ba eu X> r~; r>- ON 0 rt I-H 0 © © T-H CN* T-H d CN* ON cd rt T-H T-H T-H CO E a vo >> c: CN &F, CO CO rt rH r>- 00 rH CN r^ r^ © CO ON © r- •c c O T-H T-H •xi •G CO ON r-» r^ 00 © © iq rt © rT OH 0 ed ON O to T-H tr** od ©' T-H CO r-H d CN od t4H O TJ 2 T-H T-H CN ed rt in G .3 O s& Tl T-H CN 00 r-H CO I-H © I-H •O 0 (U r- © CN r» r- in PH > NO ON 00 VO rt i—1 ON © CN tq NO oq cq O y—^ X> i-H T-H © NO ON' © © CO CN X d •o' ~ T-H CO i-H r> s.-^ H?•> T-H CO «o B Tj H CO 0r > C (U 00 4— cd G CO rt r- 00 CO T-H 00 CO r- CO rT © i-H G CU ON ON ON vq t> CO T-H 00 © T-H CN © tq JJ T-H G 00 rG ON 00 00 ON rt VO 0 to © CO O 00 •j- II 7) T-H l-H T-H O O J> 00 00 vq P» CO 0 to CN © G PH C*H B ed © d wo i-H O* 00* © © CN* CN © CN* SO* O X O t+H i-H I-H CN 4-1 O »o 3 G rt r-H oo rH oo CN © r-- NO ON CN rt o © cd G ON rt r-1 ON rt i-H O CO vq CN IO ON cd p 1-1 T-H C*H in X ON' d rf vd © d CN* CN* rf r-* I-H i-H d O cd rt r-H CO X r- cu T-H c G i-H > O ON ON SO © CN rt OO rt CO O oo • i-H r~ r-rH- ON tq OO CN ON iq lO oq CN IO >-H ed ed —H T-H CN* T-H rf C-* o ON © to* t-* od © d X 3 rT rH CN HV- CU £ ed o CO OO to © o © VO oo CN CN vo © ON B 00 ON to CO i-H rH OO o ON to CN O CN X l-H OO o r-- ON NO i-H © CO r-- CO © rT or) o ed © vd i—i OO © CN* l-H © ! cd VH o vd T-H o r- > >N I-H cd to CN - * a, G Go ... cd •—N oo © ON CN ON rT NO to o to to O NO ed O t£ ON NO rt rH r-H rt CN O ON bl) *—> vq r~; oo vq CU X l-H ON* T-H CN* r-H © od od ! G ON* d IO* vd d X j* rt l-H i-H CO I ZJ CN I- 1C CO HcU CO C oo T-H ed O CO rt 00 OO CO r- NO rT oo r-> © CN cU 00 ON 00 t-- rH T-H CO to CN O CN o rT B X •G ed ON © NO I-H CN I-H ON OO vd od o rH o cOidl IH cd rt l-H CN o>N . 2 B OH G o TJ & r~ CO rt © CN ON r^ I-H to CO r- © CO G cu p OO ON vq rt r^ I-H r-- CN ON CN to C-- B o > X T-H rf I-H ON © ©' CN* r-H ON NO TJ o d o* d OH to rH T-H CO G oo <4H cd B T-H o o rCHU ON C/J ON G OO S-! tU r-~ r- Sample no. La Ce Sm Eu Yb Lu 921 72.7 55.5 26.7 21.4 12.9 9.4 918 123.9 82.7 35.6 26.9 13.4 13.5 832 54.2 42.9 25.6 21.4 12.2 10.9 826 147.3 97.6 40.9 33.0 14.3 12.9 823 104.2 71.7 35.5 26.7 12.3 11.8 917 87.6 47.6 30.2 23.2 13.6 12.9 824 102.4 73.9 33.0 27.1 12.8 13.2 833 93.3 59.7 26.5 19.4 11.3 11.5 326 154.5 111.1 51.9 37.8 12.9 13.8 438 81.5 57.2 24.5 21.2 10.2 10.3 417 86.7 60.5 27.1 22.2 10.7 10.3 418 63.6 58.4 34.6 31.7 10.0 10.3 Table 6-5. Observed REE contents in Ungaran lavas. All data are normalized to chondrite values of Haskin et al. (1968). 380 Sample no. La Ce Sm Eu Yb Lu 921 46.6 36.2 19.2 15.4 9.3 8.0 918 76.4 51.9 24.8 18.8 11.2 11.3 832 34.2 27.5 18.2 15.2 10.3 9.2 826 98.0 65.9 30.2 24.4 12.3 11.1 823 71.4 49.8 26.8 20.1 10.7 10.3 917 58.3 32.2 22.3 17.1 11.7 11.1 824 71.2 52.0 25.2 20.7 11.2 11.6 833 63.0 40.9 19.8 14.5 9.8 10.0 326 106.6 77.7 39.4 28.7 11.3 12.1 438 55.4 39.5 18.4 15.9 8.9 8.9 417 59.4 42.0 20.4 16.7 9.3 9.0 418 41.7 38.9 25.3 23.1 8.6 8.8 Table 6-6. Calculated REE contents in primary magma from Ungaran. All results are normalized to chondrite values of Haskin et al. (1968). 381 Mantle Degree of La Ce Sm Eu Yb Lu source melting 1% 36.6 23.9 3.3 3.3 0.58 0.52 Eclogite 5% 21.5 16.5 3.2 3.2 0.60 0.54 10% 14.1 11.9 3.1 3.1 0.62 0.56 Garnet 1% 72.5 59.8 12.9 13.0 2.34 2.10 Iherzohte 5% 30.3 28.1 11.6 11.8 2.74 2.46 10% 17.5 16.9 10.3 10.6 3.5 3.21 Spinel 1% 71.2 52.9 20.3 20.3 13.7 13.7 Iherzohte 5% 29.9 26.5 15.5 15.5 11.5 11.6 10% 17.4 16.3 11.9 11.9 9.6 9.6 Amphibole 1% 36.6 24 3.3 3.3 0.58 0.52 Iherzohte 5% 21.5 16.5 3.2 3.2 0.60 0.54 10% 14.1 11.9 3.1 3.1 0.62 0.56 Table 6-7. Calculated REE contents of melts derived by 1,5 and 10% partial melting of four possible mantle sources having twice chondritic abundances. All results are plotted in Figure 6-3. 382 Source for 5% melting Mantle La Ce Sm Eu Yb Lu Sample no. Source Eclogite 9.9 9.4 24.6 17.9 40.2 48.1 326 3.2 3.3 11.3 9.5 36.8 36.8 832 Garnet 7.0 5.5 6.8 4.9 11.8 14.1 326 lherzolite 2.3 2.0 3.1 2.6 10.8 10.8 832 Spinel 7.1 5.9 5.1 3.7 1.9 2.1 326 lherzolite 2.3 2.1 2.4 2.0 1.8 1.6 832 Amphibole 9.2 7.0 7.5 5.5 2.6 2.7 326 lherzolite 2.9 2.5 3.5 2.9 2.3 2.1 832 Source for 10% melting Mantle La Ce Sm Eu Yb Lu Sample no. Source Eclogite 15.1 13.1 25.5 18.6 41.5 49.7 326 4.8 4.6 11.8 9.8 38.0 38.0 832 Garnet 12.2 9.2 7.7 5.4 13.6 16.3 326 lherzolite 3.9 3.3 3.5 2.9 12.4 12.5 832 Spinel 12.3 9.5 6.6 4.8 2.3 2.5 326 lherzolite 3.9 3.4 3.1 2.6 2.1 1.9 832 Amphibole 13.8 10.4 8.4 6.1 2.8 3.0 326 lherzolite 4.4 3.7 3.9 3.2 2.5 2.3 832 Table 6-8. Calculated REE compositions for four mantle source assemblages. Computation is made by using calculated primary magma for samples 326 and 832 (see Table 6-6). All results are plotted in Figure 6-4. 383 APPENDIX A METHODS OF INVESTIGATION A.l Sampling Sample locations are plotted in Figure 2-10 and all samples are listed in stratigraphic order from oldest (bottom) to youngest (top), shown in the table below. Young Ungaran Parasitic Cones Old Ungaran Oldest Ungaran 437 (A) 917 (B) 924 (A) 930 (A) 438A (A) 919 (A) 923 (BA) 929 (B) 439 (BA) 423 (A) 922 (BA) 926 (B) 433 (A) 424 (A) 820 (BA) 925 (B) 834 (A) 4241 (BA) 823 (B) 921 (B) 325 (BA) 425 (BA) 832 (B) 435 (BA) 427 (A) 826 (B) 432 (BA) 428 (BA) 928 (BA) 328 (A) 426 (BA) 927 (B) 422 (A) 202 (BA) 822 (B) 416 (BA) 429 (A) 918 (B) 418 (B) 417 (B) 440 (A) 420 (A) 419 (BA) 323 (A) 320 (A) 438 (B) 320A (B) 320 (B) 833 (B) 415 (BA) 829 (BA) 828 (BA) 827 (BA) 830 (BA) 825 (BA) 824 (B) 821 (BA) (A) = andesite; (BA) = basaltic andesite; and (B) = basalt 384 A.2 Sample preparation Thin sections were prepared from the least altered specimens. Representative samples suitable for geochemical analysis were sawn into thin slabs ( < 10 mm ), reduced to small chips (maximum dimension < 8 mm) by hammering between plastic sheets and then crushed to powder in a tungsten carbide "Siebtechnik" mill. This powder was then reduced to the appropriate sample size by conventional splitting techniques. A.3 X-ray fluorescence (XRF) Analyses of all major elements except Na, together with and all trace elements except REE, Sc, Co, V, Cr, Ba, Zn, Hf and Ta were determined on an energy dispersive X-ray fluorescence spectrometer housed in the Department Geology at the University of Wollongong. The spectrometer has a silver side-window bremmstrahlung X-ray tube and utilizes a Si (Li) X-ray detector manufactured by United Scientific Corporation. The spectrometer was calibrated from widely accepted analyses of a large range of natural and artificial standards including: Primary standards Name Source GZ granite United States Geological Survey BCR-1 basalt United States Geological Survey AGV-1 andesite United States Geological Survey GSP-1 granodiorite United States Geological Survey PCC-1 peridotite United States Geological Survey NTMG granite South African Bureau of Standards NTMP pyroxenite South African Bureau of Standards NIMD dunite South African Bureau of Standards NTMS syenite South African Bureau of Standards NIML lujvarite South African Bureau of Standards NTMN norite South African Bureau of Standards 385 Calibration of the instrument and determination of the X-ray fluorescence intensity data for the standards and samples were achieved under identical operational conditions and these data were processed by a program written by Dr B.E. Chenhall, University of Wollongong. More detailed information on the equipment, operational conditions and data reduction are available in an unpublished report written by Dr B.E. Chenhall. Homogeneous glass disks of standards and samples were prepared for all major elements analyses except Na, by fusing a known weight of rock and lithium metaborate flux (spectroflux 100A) in the ratio of 1:3 at 1100°C. Flux losses were monitored by separate fusion of the lithium metaborate. Comparison of within and between run analytical data and the accepted values for the standards indicated that the analytical uncertainty at the 95% confidence level is better than 2% relative for all major elements. Homogeneous pellets of standards and unknowns were prepared for trace element analyses (Rb, Sr, Zr, Pb, Th, Nb, Y) by pressing approximately lOg of powdered rock sample with 10 drops of 5% polyvinyl alcohol in a tool steel die. The samples were oven dried at 65°C to enhance cohesion. Comparison of within and between run analytical uncertainty at the 95% confidence level is better than 2% relative for Rb and Sr, 3% relative for Y and Zr and better than 4% relative for the other trace elements. A.4 Atomic absorption spectrophotometry (AAS) The glass disks used for XRF analyses were ground into a homogeneous powder and 1 gr of the powder was used for determination of Na concentrations by atomic absorption flame spectrophotometry (AAS) using a Varian Techtron AA-175. Complete description of the AAS technique is provided in the instruction manual housed in the Department of Geology, University of wollongong. The standards used are the same as listed in Section A.3. 386 A.5 FeO determination. All FeO analyses were based on the method of Shepero and Brannock (1956). Samples were dissolved in HF with an excess of amonium metavanadate (NH4VO3) which was back-titrated against standardized Fe(NH4)2(S04)2. A.6 Instrumental neutron activation analysis (INAA) Rare earth element, Sc, Co, V, Cr, Ba, Zn, Hf and Ta concentrations were determined by an instrumental neutron activation analysis (INAA) technique described by Carr and Fardy (1984). All analytical data for these elements were obtained by John Fardy of the Division of Energy Chemistry, CSIRO. A.7 Isotope determination The strontium isotopic ratio of Ungaran lavas were measured on a single focussing 9 in 60° sector mass spectrometer. All 87Sr/86Sr ratios were normalized to an 86Sr/88Sr ratio of 0.1194, and all analyses were corrected to an E and A SrC03 standard 87Sr/86Sr ratio of 0.70800. Repeated analysis of the E and A standard during the time in which the analyses were performed give an average 87Sr/86Sr ratio of 0.708012 with two standard deviation of population of 0.000046. All isotopic analyses were carried out by Dr DJ. Whitford, CSIRO. A.8. Mineral analyses Polished thin-sections of representative samples were used for analysis of mineral phases by electron microprobe, using the method described by Reed and Ware (1975). 387 APPENDIX B MODAL MINERALOGY (VOLUME %) Appendix B-l. Oldest Ungaran Appendix B-2. Old Ungaran Appendix B-3. Parasitic Cones Appendix B-4. Young Ungaran 388 Appendix B-l. Modal mineralogy (volume %) of rocks from Oldest Ungaran. Sample 921 925 926 929 930 PHENOCRYSTS Plagioclase 24 26 18 21 21 Clinopyroxene 11.5 11 13 10 6 Fe-Ti oxide 6.5 8 4 4 3 Amphibole - - - 1 10 Mica - - - - 3 Pseudomorphs 0.25 - - - - (after olivine) GROUNDMASS 57.75 55 65 64 57 Appendix B-2. Modal mineralogy (volume %) of rocks from Old Ungaran. Sample 918 822 927 928 826 PHENOCRYSTS Plagioclase 17.5 19 26 23 23 Clinopyroxene 13.5 10 5 14 13 Fe-Ti oxide 5.5 6 7 5 5 Pseudomorphs 0.5 1 0.5 0.5 1 (after olivine) Amphibole - 1.5 - - - GROUNDMASS 63 62.5 61.5 57.5 58 389 Appendix B-2 (continued). Modal mineralogy (volume %) of rocks from Old Ungaran. Sample 832 823 820 922 923 924 PHENOCRYSTS Plagioclase 27 28 20 19 21 25 Clinopyroxene 6 9 11 7 7 4 Fe-Ti oxide 2.5 4 5 8 8 6 Pseudomorphs 2.5 1 - 0.75 0.5 - (after olivine) Amphibole - - - 1 1 5 GROUNDMASS 62 58 64 64.25 62.5 60 Appendix B-3. Modal mineralogy (volume %) of rocks from Parasitic Cones. Sample 429 202 426 428 427 PHENOCRYSTS Plagioclase 27 23 23 27 33 Clinopyroxene 6 8 8 10 5 Fe-Ti oxide 4 3 3.5 5 7 Pseudomorphs - 0.25 - - - (after olivine) Amphibole 5 - 2.5 1 - Mica 1 - - - - GROUNDMASS 57 65.75 63 57 55 390 Appendix B-3 (continued). Modal mineralogy (volume %) of rocks from Parasitic Cones. Sample 425 4241 424 423 919 917 PHENOCRYSTS Plagioclase 28 31.5 19.5 25 26 25.5 Clinopyroxene 4 6.5 10 8.5 6.5 8 Fe-Ti oxide 2 2.5 9.5 8 2 8 Pseudomorphs 1 1 - - - 1 (after olivine) Amphibole - - - 1 7 3 GROUNDMASS 65 58.5 61 57.5 58.5 55.5 Appendix B-4. Modal mineralogy (volume %) of rocks from Young Ungaran. Sample 821 824 825 830 827 828 PHENOCRYSTS Plagioclase 29 21 26 24 28 26 Clinopyroxene 6 15 8 11 3.5 9 Fe-Ti oxide 4 5 7 5 3 5 Amphibole 3 - 3 - 9 1.25 Pseudomorphs - 0.25 - 1 - 1 (after olivine) Mica - - 1 - 0.5 0.75 GROUNDMASS 58 58.75 55 59 56 57 391 Appendix B-4 (continued). Modal mineralogy (volume %) of rocks from Young Ungaran. Sample 829 415 833 326 320A 438 PHENOCRYSTS Plagioclase 21 20 27 20 22 23.5 Clinopyroxene 6 9 7 4 5 3 Fe-Ti oxide 10 4 9 5 6 5 Pseudomorph - 1 - 15 12 10.5 (after olivine) Mica - - - 1 0.5 - GROUNDMASS 63 66 57 55 54.5 58 Sample 320 323 419 420 440 417 PHENOCRYSTS Plagioclase 20 24 20.5 21.5 25 21.5 Clinopyroxene 5 5 7.5 8.5 2.5 13 Fe-Ti oxide 3.5 4 13 3.5 4 2 Amphibole 7 5 - 3.5 6 - Mica 1.5 1 - - 1 - GROUNDMASS 63 61 59 63 61.5 63.5 392 Appendix B-4 (continued). Modal mineralogy (volume %) of rocks from Young Ungaran. Sample 418 416 422 328 432 435 PHENOCRYSTS Plagioclase 25 22 27 22.5 24.5 27.5 Clinopyroxene 12 6 6.5 4 5 7 Fe-Ti oxide 7 9 6 3.5 6.5 3 Amphibol - 1.5 7.5 1.5 4 Mica - - - 2 - - GROUNDMASS 56 61.5 60.5 60.5 62.5 58.5 Sample 325 834 433 439 438 437 PHENOCRYSTS Plagioclase 20 23 25.5 26.5 22.5 23 Clinopyroxene 3 4 5 6.5 2.5 4 Fe-Ti oxide 8 3 6 7.5 4 8 Amphibole 10 9 3 1 11 - Mica - 1 0.5 - - - GROUNDMASS 59 60 60 58.5 60 65 393 APPENDIX C MINERAL CHEMISTRY First order subdivision (e.g. C-l) is for mineral types where, 1 = feldspar 2 = clinopyroxene 3 = Fe-Ti oxide 4 = amphibole 5 = olivine 6 = mica 7 = glass Second order subdivision (e.g. C-l.l) is for rock types where, 1 = basalt 2 = basaltic andesite 3 = andesite Third order subdivision (e.g. C-l.1.1) is for stratigraphic unit where 1 = Oldest Ungaran 2 = Old Ungaran 3 = Parasitic Cones 4 = Young Ungaran ABBREVIATIONS USED: Grain P = phenocrystic grain GM = groundmass grain 1,2.. = grain number Spot C = core M = between core and rim R = rim n.d. = not detected 394 Appendix C-1.1.1. Mineral chemistry of feldspars in basalt from Oldest Ungaran. Sample 925 925 925 921 921 921 921 Grain PI P2 P3 PI PI GM1 P2 Spot R R C R C C C Si02 49.57 53.71 45.76 45.65 45.08 45.54 45.11 AI2O3 26.89 29.37 34.41 34.40 34.99 34.66 33.63 FeO 2.31 0.45 0.57 1.00 0.56 0.74 0.89 MgO 2.47 0.09 0.09 0.11 0.04 0.07 0.09 CaO 16.43 11.23 17.25 16.86 17.68 17.00 18.82 Na20 2.04 4.65 1.71 1.81 1.55 1.85 1.35 K20 0.30 0.50 0.22 0.16 0.09 0.14 0.11 Total 96.93 97.27 97.10 101.10 99.93 100.68 97.27 Si 9.218 9.725 8.451 8.441 8.335 8.414 8.387 Al 5.895 6.270 7.492 7.499 7.627 7.550 7.371 Fe 0.359 0.068 0.088 0.155 0.087 0.114 0.138 Mg 0.685 0.024 0.025 0.030 0.011 0.019 0.025 Ca 3.274 2.179 3.414 3.341 3.503 3.366 3.749 Na 0.736 1.633 0.612 0.649 0.556 0.663 0.487 K 0.071 0.116 0.052 0.038 0.021 0.033 0.026 Total 20.238 20.015 20.134 20.153 20.140 20.159 20.183 An 80.23 55.48 83.71 82.95 85.86 82.87 87.97 Ab 18.03 41.57 15.02 16.11 13.62 16.32 11.40 Or 1.74 2.94 1.27 0.94 0.52 0.81 0.61 395 Appendix C-1.1.1 (continued). Mineral chemistry of feldspars in basalt from Oldest Ungaran. Sample 921 921 921 921 921 921 Grain P2 GM2 P3 P4 P4 P4 Spot R C C C R M Si02 46.39 56.97 47.05 44.01 47.22 43.96 AI2O3 34.22 25.50 33.58 35.82 31.98 35.95 FeO 0.82 1.82 0.87 0.53 2.98 0.59 MgO 0.09 0.29 0.09 0.10 0.72 0.10 CaO 16.97 7.72 16.60 18.94 14.75 19.04 Na20 1.39 4.53 1.67 0.50 1.96 0.30 K20 0.12 3.16 0.13 0.10 0.39 0.06 Total 98.89 97.11 98.65 100.86 98.98 98.69 Si 8.545 10.378 8.661 8.150 8.759 8.138 Al 7.431 5.476 7.288 7.820 6.994 7.846 Fe 0.126 0.277 0.134 0.082 0.462 0.091 Mg 0.025 0.079 0.025 0.028 0.199 0.028 Ca 3.349 1.507 3.274 3.758 2.932 3.777 Na 0.496 1.600 0.596 0.180 0.705 0.108 K 0.028 0.734 0.031 0.024 0.092 0.014 Total 20.000 20.051 20.009 20.042 20.143 20.002 An 86.46 39.23 83.94 94.87 78.62 96.87 Ab 12.82 41.65 15.28 4.53 18.91 2.76 Or 0.73 19.12 0.78 0.60 2.48 .37 396 Appendix C-l. 1.2. Mineral chemistry of feldspars in basalt from Old Ungaran. Sample 918 918 918 918 918 918 918 918 Grain PI PI PI P2 P2 P2 GM1 GM2 Spot R C M R M C C C SiC_ 51.33 47.54 46.97 52.25 49.48 44.44 53.78 50.53 AI2O3 30.84 33.28 33.57 29.92 31.79 35.26 29.20 31.28 FeO 0.51 0.48 0.58 0.60 0.51 0.53 0.57 0.52 MgO 0.07 0.03 0.03 0.05 0.07 0.03 0.03 0.03 CaO 13.03 16.28 16.74 12.47 14.81 18.77 11.30 13.91 Na20 3.88 2.22 1.98 4.31 3.12 0.92 4.68 3.44 K20 0.34 0.16 0.13 0.40 0.21 0.05 0.44 0.29 Total 99.76 99.48 99.67 100.01 99.77 99.59 99.69 99.94 Si 9.350 8.739 8.649 9.512 9.061 8.232 9.743 9.225 Al 6.623 7.212 7.288 6.421 6.864 7.70 6.236 6.732 Fe 0.078 0.074 0.089 0.091 0.078 0.082 0.086 0.079 Mg 0.019 0.008 0.008 0.014 0.019 0.008 0.008 0.008 Ca 2.543 3.207 3.303 2.432 2.906 3.725 2.193 2.721 Na 1.370 0.791 0.707 1.521 1.108 0.330 1.644 1.218 K 0.079 0.038 0.031 0.093 0.049 0.012 0.102 0.068 Total 20.062 20.069 20.075 20.084 20.085 20.089 20.012 20.051 An 63.70 79.46 1.75 60.11 71.53 91.59 55.68 67.92 Ab 34.32 19.61 17.50 37.60 27.27 8.12 41.73 30.40 Or 1.98 0.93 0.76 2.3 1.21 0.29 2.58 1.69 397 Appendix C-l. 1.2 (continued). Mineral chemistry of feldspars in basalt from Old Ungaran. Sample 822 822 822 822 826 826 826 826 Grain PI PI P2 P3 PI PI PI GM1 Spot C R C C R C R C Si02 44.43 48.62 49.84 49.90 48.01 47.22 47.06 45.94 AI2Q3 35.61 32.72 31.82 31.61 33.04 33.45 33.51 34.39 FeO 0.62 0.49 0.74 0.68 0.49 0.57 0.64 0.83 MgO 0.09 0.09 0.10 0.09 0.03 0.03 0.05 0.04 CaO 18.63 15.58 14.50 14.25 15.35 16.05 15.98 16.68 Na20 0.55 2.31 2.76 3.01 2.85 2.49 2.56 1.96 K20 0.06 0.20 0.25 0.45 0.23 0.19 0.20 0.16 Total 99.13 99.66 100.79 99.20 100.99 101.28 102.04 101.39 Si 8.217 8.905 9.109 9.131 8.816 8.692 8.669 8.482 Al 7.765 7.065 6.856 6.819 7.153 7.259 7.277 7.485 Fe 0.096 0.075 0.113 0.104 0.075 0.088 0.099 0.128 Mg 0.025 0.025 0.027 0.025 0.008 0.008 0.014 0.011 Ca 3.692 3.058 2.840 2.794 3.020 3.166 3.154 3.300 Na 0.197 0.820 0.978 1.068 1.015 0.889 0.914 0.702 K 0.014 0.047 0.058 0.105 0.054 0.045 0.047 0.038 Total 20.006 19.995 19.981 20.046 20.141 20.147 20.174 20.146 An 94.58 77.91 73.26 70.43 73.86 77.23 76.64 81.70 Ab 5.05 20.90 5.23 26.92 24.82 21.68 22.22 17.37 Or 0.36 1.19 1.50 2.65 1.32 1.09 1.14 0.93 398 Appendix C-l. 1.2 (continued). Mineral of feldspars in basalt from Old Ungaran. Sample 826 826 832 832 832 832 832 832 832 Grain GM2 GM3 PI PI P2 P2 P3 P3 GM1 Spot C C C R C R C R C Si02 49.51 48.11 49.89 49.87 46.95 46.83 49.72 50.43 57.66 Al203 31.99 32.79 31.60 31.71 33.69 33.83 31.80 30.99 25.77 FeO 0.69 0.68 0.78 0.72 .86 0.77 0.62 0.73 1.13 MgO 0.02 0.04 0.09 0.09 0.09 0.09 0.09 0.09 0.09 CaO 14.17 15.37 14.30 14.38 16.42 16.57 14.48 14.21 7.36 Na20 3.36 2.76 2.99 2.97 1.78 1.74 3.03 3.22 4.84 K20 0.26 0.25 0.35 0.26 0.21 0.18 0.26 0.34 3.15 Total 102.12 101.53 98.46 99.38 97.22 98.94 99.99 101.71 98.73 Si 9.063 8.841 9.128 9.119 8.645 8.621 9.094 9.223 10.450 Al 6.904 7.104 6.816 6.836 7.314 7.342 6.857 6.682 5.506 Fe 0.106 0.105 0.119 0.100 0.132 0.119 0.095 0.112 0.171 Mg 0.005 0.011 0.025 0.025 0.025 0.025 0.025 0.025 0.024 Ca 2.779 3.026 2.804 2.817 3.240 3.269 2.838 2.785 1.429 Na 1.193 0.983 1.061 1.053 0.636 0.621 1.075 1.142 1.701 K 0.061 0.059 0.082 0.061 0.049 0.042 0.061 0.079 0.728 Total 20.111 20.129 20.035 20.021 20.041 20.039 20.045 20.048 20.009 An 68.92 74.39 71.05 71.67 82.55 83.13 71.43 69.51 37.04 Ab 29.57 24.17 26.88 26.79 16.19 15.80 27.05 28.51 44.08 Or 1.51 1.44 2.07 1.54 1.26 1.08 1.53 1.98 18.88 399 Appendix C-l. 1.3. Mineral chemistry of feldspars in basalt from Parasitic Sample 917 917 917 917 917 917 Grain GM2 PI PI PI PI P2_ Spot C R C M II R_ Si02 49.36 49.24 47.76 48.23 52.12 54.91 AI2O3 32.11 32.21 33.20 32.79 30.16 28.75 FeO 0.66 0.59 0.53 0.67 0.79 0.50 MgO 0.03 0.04 0.04 0.05 0.08 0.09 CaO 14.32 14.71 15.80 15.38 12.46 10.23 Na20 3.24 3.06 2.53 2.72 4.14 5.08 K20 0.27 0.15 0.14 0.16 0.25 0.45 Total 101.45 100.67 100.95 100.37 100.06 99.96 Si 9.038 9.013 8.773 8.855 9.483 9.906 Al 6.932 6.951 7.190 7.097 6.469 6.114 Fe 0.101 0.090 0.081 0.103 0.120 0.075 Mg 0.008 0.011 0.011 0.014 0.022 0.024 Ca 2.810 2.885 3.110 3.026 2.429 1.977 Na 1.150 1.086 0.901 0.968 1.461 1.777 K 0.063 0.035 0.033 0.037 0.058 0.104 Total 20.102 20.071 20.099 20.10 20.042 19.977 An 69.84 72.02 76.90 75.05 61.53 51.26 Ab 28.59 27.11 22.28 24.02 37.00 46.06 Or 1.57 0.87 0.81 0.93 1.47 2.68 400 Appendix C-l. 1.4. Mineral chemistry of feldspars in basalt from Young Ungaran. Sample 833 833 833 833 833 833 326 326 Grain PI PI P2 P2 P3 P3 PI PI Spot C R C R R C R C SiC_ 56.96 56.20 52.21 52.46 51.15 57.22 46.56 45.19 AI2O3 27.24 27.67 30.29 30.02 30.82 27.34 33.45 34.83 FeO 0.45 0.33 0.56 0.60 0.75 0.53 0.68 0.28 MgO 0.09 0.09 0.09 0.09 0.09 0.09 0.05 0.02 CaO 8.77 9.41 12.46 12.48 13.35 8.43 17.11 18.21 Na20 5.74 5.55 4.09 3.89 3.54 5.76 2.03 1.42 K20 0.75 0.76 0.29 0.45 0.30 0.63 0.12 0.05 Total 98.48 97.71 98.59 97.52 98.47 97.39 99.75 100.18 Si 10.238 10.121 9.488 9.534 9.327 10.265 8.598 8.351 Al 5.772 5.875 6.489 6.432 6.625 5.782 7.282 7.588 Fe 0.068 0.050 0.085 0.091 0.114 0.080 0.105 0.043 Mg 0.024 0.024 0.024 0.024 0.024 0.024 0.014 0.006 Ca 1.689 1.816 2.426 2.430 2.608 1.620 3.385 3.606 Na 2.000 1.938 1.441 1.371 1.252 2.004 0.727 0.509 K 0.172 0.175 0.067 0.104 0.070 0.144 0.028 0.012 Total 19.963 19.999 20.020 19.986 20.020 19.919 20.139 20.115 An 43.74 46.22 61.66 62.23 66.37 43.00 81.76 87.38 Ab 51.81 49.33 36.63 35.10 31.85 53.17 17.55 12.33 Or 4.45 4.44 1.71 2.67 1.78 3.83 0.68 0.29 401 Appendix C-l. 1.4 (continued). Mineral chemistry of feldspars in basalt from Young Ungaran. Sample 326 326 326 326 438 438 438 438 Grain P2 P2 GM1 P3 PI P2 P2 P3 Spot C R C C R C R C Si02 49.40 48.73 47.88 51.04 57.06 57.74 57.14 55.10 AI2O3 31.91 32.48 32.98 31.08 27.27 27.21 26.93 28.18 FeO 0.88 0.80 0.85 0.82 0.57 0.84 0.83 0.71 MgO 0.10 0.09 0.10 0.10 0.09 0.09 0.09 0.10 CaO 15.12 15.25 16.08 13.38 8.53 8.28 8.19 9.97 Na20 1.86 2.46 1.93 3.36 5.91 5.45 5.39 5.01 K20 0.73 0.20 0.18 0.23 0.57 0.40 1.43 0.94 Total 101.39 99.94 100.99 1L 00.43 99.80 99.70 98.67 99.64 Si 9.055 8.933 8.798 9.30 10.247 10.331 10.293 9.966 Al 6.895 7.02 7.144 6.677 5.774 5.74 5.719 6.009 Fe 0.135 0.123 0.131 0.125 0.086 0.126 0.125 0.107 Mg 0.027 0.025 0.027 0.027 0.024 0.024 0.024 0.027 Ca 2.97 2.996 3.166 2.612 1.641 1.587 1.581 1.932 Na 0.661 0.874 0.688 1.187 2.058 1.891 1.883 1.757 K 0.171 0.047 0.042 0.053 0.131 0.091 0.329 0.217 Total 19.914 20.018 19.996 19.981 19.961 19.79 19.954 20.015 An 78.12 76.48 81.27 67.80 42.86 44.47 41.69 49.47 Ab 17.39 22.33 17.65 30.81 53.73 52.97 49.65 44.98 Or 4.49 1.19 1.08 1.39 3.41 2.56 8.67 5.55 402 Appendix C-l. 1.4 (continued). Mineral chemistry of feldspars in basalt from Young Ungaran. Sample 438 438 438 438 320 320 320 320 Grain P3 P4 P4 P5 PI PI P2 P2 Spot R C R C C R C R SiC_ 53.27 52.16 49.70 49.09 62.51 46.44 49.68 47.67 AI2O3 28.89 29.83 31.94 32.33 21.48 33.92 30.55 33.39 FeO 1.33 0.92 0.61 0.69 1.90 0.76 1.56 0.59 MgO 0.09 0.10 0.10 0.10 0.23 0.10 0.13 0.09 CaO 12.12 12.73 14.84 14.98 6.59 16.97 14.47 15.95 Na20 3.15 3.05 2.60 2.61 3.33 1.66 2.16 2.10 K20 1.15 1.23 0.22 0.21 3.96 0.16 1.46 0.21 Total 99.38 99.74 99.31 100.62 99.79 101.97 99.71 100.66 Si 9.705 9.518 9.083 8.987 11.253 8.563 9.167 8.753 Al 6.205 6.417 6.881 6.978 4.559 7.374 6.646 7.228 Fe 0.203 0.140 0.093 0.106 0.286 0.117 0.241 0.091 Mg 0.024 0.027 0.027 0.027 0.062 0.027 0.036 0.025 Ca 2.366 2.489 2.906 2.939 1.271 3.353 2.861 3.138 Na 1.113 1.079 0.921 0.927 1.162 0.594 0.773 0.748 K 0.267 0.286 0.051 0.049 0.910 0.038 0.344 0.049 Total 19.883 19.956 19.962 20.013 19.503 20.066 20.068 20.032 An 63.16 64.57 74.92 75.08 38.02 84.16 71.93 79.75 Ab 29.71 28.00 23.75 23.67 34.77 14.90 19.43 19.00 Or .14 7.43 1.32 1.25 27.21 0.94 8.64 1.25 403 Appendix C-l. 1.4 (continued). Mineral chemistry of feldspars in basalt from Young Ungaran. Sample 418 418 418 418 418 418 418 Grain GM1 GM2 PI PI PI PI P2 Spot C C R C M R C Si02 52.72 52.39 50.40 48.75 51.28 49.01 50.40 AI2O3 29.10 29.81 30.92 32.15 30.63 32.23 31.04 FeO 1.37 0.85 0.70 0.52 0.69 0.57 0.81 MgO 0.30 0.13 0.05 0.02 0.03 0.04 0.14 CaO 11.33 11.86 13.96 15.37 12.94 14.78 14.11 Na20 4.54 4.60 3.68 2.94 4.07 3.10 3.08 K20 0.64 0.36 0.29 0.26 0.36 0.27 0.42 Total 98.53 99.79 99.34 98.60 99.40 99.33 99.40 Si 9.616 9.536 9.224 8.950 9.356 8.984 9.219 Al 6.257 6.397 6.671 6.958 6.588 6.965 6.693 Fe 0.209 0.129 0.107 0.080 0.105 0.087 0.124 Mg 0.082 0.035 0.014 0.005 0.008 0.011 0.038 Ca 2.214 2.313 2.738 3.024 2.530 2.903 2.765 Na 1.606 1.624 1.306 1.047 1.440 1.102 1.092 K 0.149 0.084 0.068 0.061 0.084 0.063 0.098 Total 20.133 20.118 20.128 20.125 20.111 20.115 20.029 An 55.79 57.54 66.59 73.19 62.41 71.36 69.91 Ab 40.46 40.38 31.76 25.33 35.52 27.09 27.61 Or 3.75 2.08 1.65 1.47 2.07 1.55 2.48 404 Appendix C-l. 1.4 (continued). Mineral chemistry of feldspars in basalt from Young Ungaran. Sample 418 418 418 418 418 418 418 Grain P2 P3 P3 GM1 GM2 P4 P4 Spot R C R C C C R Si02 50.27 50.36 52.34 63.85 55.42 50.89 52.26 AI2O3 30.24 31.09 29.77 20.60 26.90 31.16 29.98 FeO 2.21 0.96 0.92 0.65 1.13 0.61 0.92 MgO 0.68 0.10 0.09 0.09 0.09 0.10 0.10 CaO 13.19 13.81 12.40 1.51 9.80 13.67 12.39 Na20 2.96 3.37 4.05 4.45 4.53 3.18 3.94 K20 0.45 0.31 0.43 8.84 2.12 0.39 0.40 Total 99.21 101.00 101.43 99.65 98.79 101.02 101.90 Si 9.236 9.213 9.532 11.584 10.092 9.278 9.512 Al 6.550 6.706 6.392 4.406 5.775 6.697 6.433 Fe 0.340 0.147 0.140 0.099 0.172 0.093 0.140 Mg 0.186 0.027 0.024 0.024 0.024 0.027 0.027 Ca 2.597 2.707 2.420 0.294 1.912 2.670 2.416 Na 1.055 1.195 1.430 1.565 1.599 1.124 1.391 K 0.105 0.072 0.100 2.046 0.493 0.091 0.093 Total 20.069 20.067 20.038 20.018 20.067 19.980 20.012 An 69.12 68.11 61.26 7.52 47.75 68.73 61.96 Ab 28.07 30.07 36.21 40.09 39.95 28.93 35.66 Or 2.81 1.82 2.53 52.40 12.30 2.33 2.38 405 Appendix C-l.2.1. (Mineral chemistry of feldspars in basaltic andesite from Old Ungaran. Sample 820 820 820 820 922 922 922 922 922 Grain PI PI GM1 GM2 PI PI P2 P2 GM1 Spot R C C C R C R C C Si02 46.95 47.29 52.20 52.34 51.22 48.69 51.58 50.30 45.19 AI2O3 33.69 33.53 29.96 29.97 31.12 32.31 30.43 31.18 34.72 FeO 0.61 0.72 0.84 0.67 0.64 0.68 0.66 0.65 0.64 MgO 0.04 0.10 0.06 0.06 0.06 0.04 0.05 0.05 0.03 CaO 16.57 16.06 12.29 12.24 12.68 15.22 12.67 13.99 18.04 Na20 2.00 2.12 4.18 4.27 3.92 2.84 4.20 3.54 1.31 K20 0.14 0.18 0.47 0.45 0.36 0.21 0.41 0.29 0.07 Total 100.09 :101.7 2 101.37 101.16 100.90 99.87 99.65 99.67 :100.0 1 Si 8.643 8.697 9.507 9.523 9.328 8.937 9.404 9.200 8.359 Al 7.312 7.270 6.433 6.429 6.681 6.992 6.541 6.723 7.571 Fe 0.094 0.111 0.128 0.102 0.097 0.104 0.101 0.099 0.099 Mg 0.011 0.027 0.016 0.016 0.016 0.011 0.014 0.014 0.008 Ca 3.268 3.165 2.398 2.386 2.474 2.993 2.475 2.742 3.575 Na 0.714 0.756 1.476 1.506 1.384 1.011 1.485 1.255 0.470 K 0.033 0.042 0.109 0.104 0.084 0.049 0.095 0.068 0.017 Total 20.075 20.068 20.067 20.066 20.064 20.097 20.115 20.101 20.099 An 81.40 79.86 60.20 59.70 62.77 73.85 61.04 67.45 88.03 Ab 17.78 19.08 37.05 37.69 35.11 24.94 36.61 30.89 11.57 Or 0.82 1.07 2.74 2.61 2.12 1.21 2.35 .66 0.41 406 Appendix C-1.2.2. Mineral chemistry of feldspars in basaltic andesite from Parasitic Cones. Sample 425 425 425 425 425 425 425 425 425 Grain PI PI PI P2 P2 P2 GM1 GM2 GM3 Spot R C M R C R C C C Si02 45.61 43.92 43.76 51.75 53.59 51.51 47.31 64.64 62.68 AI2O3 34.19 35.30 35.66 30.33 29.03 30.56 33.03 20.20 22.05 FeO 0.64 0.58 0.58 0.43 0.46 0.43 0.68 0.32 0.57 MgO 0.04 0.03 0.03 0.02 0.02 0.03 0.03 0.03 0.03 CaO 17.91 19.30 19.16 13.10 11.62 13.07 16.66 1.25 3.27 Na20 1.53 0.83 0.77 3.97 4.78 4.01 2.16 5.06 6.25 K20 0.08 0.04 0.04 0.40 0.50 0.39 0.13 8.50 5.15 Total 99.84 99.74 100.52 99.64 100.03 100.46 99.36 100.50 100.12 Si 8.436 8.157 8.122 9.427 9.725 9.386 8.717 11.688 11.286 Al 7.456 7.729 7.803 6.514 6.211 6.565 7.175 4.306 4.681 Fe 0.099 0.090 0.090 0.066 0.070 0.066 0.105 0.048 0.086 Mg 0.011 0.008 0.008 0.005 0.005 0.008 0.008 0.008 0.008 Ca 3.550 3.841 3.810 2.557 2.259 2.552 3.289 0.242 0.631 Na 0.549 0.299 0.277 1.402 1.682 1.417 0.772 1.774 2.182 K 0.019 0.009 0.009 0.093 0.116 0.091 0.031 1.961 1.183 Total 20.120 20.133 20.119 20.064 20.068 20.085 20.097 20.027 20.057 An 86.21 92.57 93.01 63.10 55.69 62.86 80.39 6.09 15.79 Ab 13.33 7.20 6.76 34.61 41.46 34.90 18.86 44.61 54.61 Or 0.46 0.23 0.23 2.29 2.85 2.23 0.75 49.30 29.61 407 Appendix C-l2.2 (continued). Mineral chemistry of feldspars in basaltic andesite from Parasitic Cones. Sample 425 425 425 425 425 425 425 425 425 Grain P3 P4 P4 P5 P5 P6 P6 P7 P7 Spot C C R C R C R C R SiC_ 51.93 46.51 52.34 55.70 51.74 51.94 54.03 57.94 51.48 AI2O3 30.50 33.84 29.85 28.13 30.30 30.27 P2.9 26.03 30.53 FeO 0.57 0.55 0.94 0.41 0.59 0.64 0.66 0.71 0.69 MgO 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.09 0.10 CaO 12.86 17.16 12.63 9.86 13.05 12.95 11.34 8.30 13.32 5.72 3.55 Na20 3.68 1.65 3.83 4.99 3.78 3.67 4.45 1.20 0.32 K20 0.36 0.20 0.32 0.81 0.46 0.42 0.43 Total 99.96 98.81 98.15 99.77 100.54 99.96 99.75 99.69 98.48 Si 9.442 8.574 9.524 10.039 9.426 9.455 9.780 10.425 9.382 Al 6.538 7.355 6.404 5.977 6.508 6.496 6.189 5.522 6.559 Fe 0.087 0.085 0.143 0.062 0.090 0.097 0.100 0.107 0.105 Mg 0.027 0.027 0.027 0.027 0.027 0.027 0.027 0.024 0.027 Ca 2.505 3.390 2.463 1.904 2.548 2.526 2.199 1.600 2.601 Na 1.297 0.590 1.351 1.744 1.335 1.295 1.562 1.996 1.254 K 0.084 0.047 0.074 0.186 0.107 0.098 0.099 0.275 0.074 Total 19.980 20.068 19.986 19.939 20.041 19.994 19.956 19.949 20.002 An 64.47 84.18 63.33 49.66 63.85 64.46 56.97 41.34 66.19 Ab 33.38 14.65 34.76 45.48 33.47 33.06 40.46 51.55 31.92 7.12 1.89 Or 2.15 1.17 1.91 4.86 2.68 2.49 2.57 408 Appendix C-l.2.2 (continued). Mineral chemistry of feldspars in basaltic andesite from Parasitic Cones. Sample 425 425 425 425 425 425 425 425 425 Grain P8 P8 P9 P9 PI PI PH PH PH Spot C R C R C R SiC_ 48.03 51.74 54.43 51.86 52.32 54.97 45.66 46.13 47.98 AI2O3 32.98 30.26 28.96 30.47 29.87 28.18 34.38 34.25 32.85 FeO 0.70 0.79 0.55 0.75 0.78 0.82 0.71 0.78 0.57 MgO 0.10 0.10 0.10 0.10 0.10 0.09 0.10 0.10 0.10 CaO 15.75 13.06 10.93 12.99 12.39 10.52 17.72 17.31 16.18 Na20 2.17 3.68 4.43 3.55 4.09 4.96 1.26 1.31 2.07 K20 0.27 0.37 0.60 0.29 0.45 0.47 0.18 0.12 0.25 Total 100.04 98.85 99.64 99.45 100.55 100.79 100.99 101.44 100.73 Si 8.820 9.429 9.837 9.433 9.524 9.940 8.437 8.507 8.815 Al 7.140 6.501 6.170 6.534 6.410 6.007 7.489 7.446 7.115 Fe 0.107 0.120 0.083 0.114 0.119 0.124 0.110 0.120 0.088 Mg 0.027 0.027 0.027 0.027 0.027 0.024 0.028 0.027 0.027 Ca 3.099 2.550 2.116 2.532 2.417 2.038 3.508 3.420 3.185 Na 0.773 1.300 1.552 1.252 1.444 1.739 0.451 0.468 0.737 K 0.063 0.086 0.138 0.067 0.105 0.108 0.042 0.028 0.059 Total 20.029 20.013 19.923 19.959 20.046 19.980 20.065 20.016 20.026 An 78.76 64.78 55.59 65.74 60.95 52.46 87.66 87.32 80.01 Ab 19.64 33.03 40.77 32.51 36.41 44.75 11.28 11.96 18.52 Or 1.61 2.19 3.63 1.75 2.64 2.79 1.06 0.72 1.47 409 Appendix C-l.2.2 (continued). Mineral chemistry of feldspars in basaltic andesite from Parasitic Cones. Sample 425 425 425 425 425 425 425 425 425 Grain Pll P12 P12 GM4 P13 P13 P14 P1'4 GM5 Spot R C R C C R C R C Si02 50.12 45.77 64.67 49.84 46.16 63.80 51.89 53.40 64.80 AI2O3 31.54 34.18 20.28 31.59 33.73 20.72 30.16 27.81 20.15 FeO 0.74 0.81 0.47 0.73 1.43 1.39 0.80 1.62 0.68 MgO 0.10 0.10 0.09 0.10 0.10 0.40 0.10 0.51 0.09 CaO 14.43 17.83 1.61 14.60 16.90 2.33 12.98 11.61 1.30 Na20 2.76 1.26 4.52 2.84 1.45 5.64 3.59 4.49 4.71 K20 0.31 0.06 8.36 0.30 0.22 5.71 0.48 0.56 8.26 Total 99.57 100.17 99.09 99.34 98.06 99.47 98.92 98.23 99.61 Si 9.159 8.458 11.681 9.119 8.540 11.495 9.455 9.751 11.704 Al 6.795 7.446 4.318 6.814 7.357 4.401 6.479 5.987 4.291 Fe 0.113 0.125 0.071 0.112 0.221 0.209 0.122 0.247 0.103 Mg 0.027 0.028 0.024 0.027 0.028 0.107 0.027 0.139 0.024 Ca 2.825 3.530 0.312 2.862 3.350 0.450 2.534 2.272 0.252 Na 0.978 0.451 1.583 1.008 0.520 1.970 1.268 1.590 1.650 K 0.072 0.014 1.926 0.070 0.052 1.313 0.112 0.130 1.903 Total 19.969 20.052 19.915 20.012 20.068 19.945 19.997 20.116 19.927 An 72.90 88.35 8.15 72.65 85.41 12.05 64.74 56.91 6.61 Ab 25.23 11.30 41.43 25.57 13.26 52.79 32.40 39.83 43.36 Or 1.86 0.35 50.42 1.78 1.32 35.16 2.85 3.27 50.03 410 Appendix C-l.2.2 (continued). Mineral chemistry of feldspars in basaltic andesite from Parasitic Cones. Sample 425 425 425 425 425 425 425 425 425 Grain P15 P15 P16 P16 P16 P17 P17 P18 P18 Spot C R C M R C R C R S-O2 60.35 54.64 44.49 46.13 64.29 54.27 55.86 54.92 50.67 A1203 23.50 28.11 35.06 33.96 19.89 28.73 27.33 28.84 31.15 FeO 1.16 1.11 0.73 1.04 0.86 0.64 1.26 0.23 0.58 MgO 0.09 0.10 0.09 0.13 0.09 0.10 0.10 0.10 0.10 CaO 5.42 10.69 18.72 17.19 1.16 11.04 9.52 10.68 13.90 Na20 5.45 4.87 0.80 1.28 4.06 4.81 5.07 4.69 3.27 K20 4.03 0.48 0.10 0.27 9.65 0.41 0.86 0.54 0.33 Total 97.87 99.62 97.70 98.39 97.02 102.22 99.83 100.54 101.24 Si 10.909 9.904 8.247 8.522 11.693 9.823 10.104 9.900 9.248 Al 5.008 6.007 7.662 7.397 4.265 6.131 5.828 6.129 6.702 Fe 0.175 0.168 0.113 0.161 0.131 0.097 0.191 0.035 0.089 Mg 0.024 0.027 0.025 0.036 0.024 0.027 0.027 0.027 0.027 Ca 1.050 2.076 3.718 3.403 0.226 2.141 1.845 2.063 2.718 Na 1.910 1.712 0.288 0.459 1.432 1.688 1.778 1.639 1.157 K 0.929 0.111 0.024 0.064 2.239 0.095 0.198 0.124 0.077 Total 20.005 20.005 20.077 20.042 20.010 20.002 19.971 19.917 20.018 An 26.99 53.25 92.28 86.70 5.80 54.57 48.28 53.91 68.78 Ab 49.11 43.90 7.14 11.68 36.74 43.02 46.53 42.84 29.28 Or 23.90 2.85 0.59 1.62 57.46 2.41 5.19 3.25 1.94 411 Appendix C-l.2.2 (continued). Mineral chemistry of feldspars in basaltic andesite from Parasitic Cones. Sample 425 425 425 425 425 425 425 425 425 Grain P19 P19 P20 P20 GM6 GM7 P21 P21 P22 Spot C R C R C C C R C SiC_ 49.63 52.00 46.90 52.93 48.26 48.03 54.01 54.21 47.63 AI2O3 31.82 30.50 33.50 29.87 32.81 32.28 28.23 28.58 33.19 FeO 0.83 0.78 0.89 0.77 0.87 1.60 0.72 0.72 0.70 MgO 0.10 0.10 0.10 0.10 0.10 0.27 0.12 0.09 0.10 CaO 14.65 12.79 16.75 12.07 15.39 15.38 10.40 10.92 16.31 Na20 2.70 3.51 1.68 3.91 2.35 2.14 5.73 4.61 1.95 K20 0.26 0.32 0.18 0.34 0.22 0.30 0.79 0.87 0.12 Total 99.84 100.35 101.86 101.37 101.71 101.81 101.14 100.11 100.03 Si 9.083 9.452 8.644 9.601 8.859 8.852 9.824 9.833 8.753 Al 6.865 6.536 7.279 6.388 7.100 7.014 6.054 6.111 7.191 Fe 0.127 0.119 0.137 0.117 0.134 0.247 0.110 0.109 0.108 Mg 0.027 0.027 0.027 0.027 0.027 0.074 0.033 0.024 0.027 Ca 2.873 2.491 3.308 2.346 3.027 3.037 2.027 2.122 3.212 Na 0.958 1.237 0.600 1.375 0.836 0.765 2.021 1.621 0.695 K 0.061 0.074 0.042 0.079 0.052 0.071 0.183 0.201 0.028 Total 19.994 19.936 20.037 19.933 20.035 20.060 20.252 20.021 20.014 An 73.82 65.51 83.73 61.74 77.32 78.43 47.90 53.80 81.63 Ab 24.62 32.54 15.20 36.19 21.36 19.75 47.76 41.10 17.66 Or 1.56 1.95 1.07 2.07 1.32 1.82 4.33 5.10 0.72 [ 412 Appendix C-l.2.2 (continued). Mineral chemistry of feldspars in basaltic andesite from Parasitic Cones. Sample 425 425 425 425 425 425 425 425 425 Grain P22 P23 GM8 GM9 P24 P24 P25 P26 P27 Spot R C C C C R C C C SiC_ 51.29 46.34 55.63 64.01 51.97 55.98 49.11 50.59 45.20 AI2O3 30.88 33.96 27.72 20.22 25.62 26.87 32.31 31.31 34.85 FeO 0.60 0.83 1.00 0.62 0.27 0.85 0.82 0.78 0.78 MgO 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.11 0.10 CaO 13.43 17.22 9.92 1.37 8.27 9.46 14.77 14.03 18.09 Na20 3.41 1.40 5.17 3.48 13.04 4.16 2.65 2.98 0.93 K20 0.29 0.15 0.46 10.20 0.72 2.58 0.23 0.21 0.06 Total 98.65 100.21 101.67 100.44 99.82 100.15 100.25 100.28 100.05 Si 9.340 8.548 10.046 11.652 9.692 10.169 8.994 9.229 8.353 Al 6.630 7.385 5.902 4.339 5.633 5.755 6.976 6.733 7.593 Fe 0.091 0.128 0.151 0.094 0.042 0.129 0.126 0.119 0.121 Mg 0.027 0.027 0.027 0.027 0.028 0.027 0.027 0.030 0.028 Ca 2.621 3.403 1.920 0.267 1.653 1.841 2.898 2.742 3.582 Na 1.204 0.501 1.810 1.228 4.716 1.465 0.941 1.054 0.333 K 0.067 0.035 0.106 2.369 0.171 0.598 0.054 0.049 0.014 Total 19.980 20.027 19.962 19.976 21.935 19.984 20.016 19.956 20.024 An 67.33 86.39 50.04 6.91 25.27 47.16 74.45 71.32 91.16 Ab 30.94 12.71 47.20 31.79 72.11 37.53 24.17 27.41 8.48 Or 1.73 0.90 2.76 61.30 2.62 15.31 1.38 1.27 0.36 413 Appendix C-l.2.2 (continued). Mineral chemistry of feldspars in basaltic andesite from Parasitic Cones. Sample 425 425 425 425 425 425 427 427 427 Grain P28 P29 P30 P30 P31 P32 PI PI PI Spot C C C R C R R C M Si02 44.86 45.44 57.83 50.48 45.17 53.99 56.79 50.55 49.91 AI2O3 35.28 34.84 25.91 31.57 34.94 29.12 26.84 31.18 31.72 FeO 0.54 0.74 1.02 0.64 0.74 0.72 0.60 0.33 0.37 MgO 0.10 0.10 0.17 0.10 0.09 0.09 0.04 0.06 0.05 CaO 18.31 17.91 8.03 13.91 17.98 10.87 8.85 13.97 14.48 Na20 0.82 0.91 5.85 3.06 0.94 4.65 6.08 3.67 3.27 K20 0.10 0.06 1.19 0.24 0.15 0.57 0.80 0.24 0.20 Total 101.33 101.19 99.49 101.11 1 01.36 101.70 ;100.6 4 99.77 101.15 Si 8.289 8.387 10.419 9.205 8.348 9.776 10.239 9.228 9.121 Al 7.685 7.581 5.503 6.786 7.613 6.216 5.705 6.711 6.834 Fe 0.083 0.114 0.154 0.098 0.114 0.109 0.09 0.05 0.057 Mg 0.028 0.028 0.046 0.027 0.025 0.024 0.011 0.016 0.014 Ca 3.625 3.542 1.55 2.718 3.56 2.109 1.71 2.733 2.835 Na 0.294 0.326 2.044 1.082 0.337 1.633 2.125 1.299 1.159 K 0.024 0.014 0.274 0.056 0.035 0.132 0.184 0.056 0.047 Total 20.028 19.992 19.99 19.972 20.032 19.999 20.064 20.093 20.067 An 91.95 91.25 40.08 70.49 90.54 54.45 42.54 66.85 70.17 Ab 7.45 8.39 52.84 28.06 8.57 42.15 52.88 31.78 28.68 Or 0.60 0.36 7.07 1.45 0.90 3.40 4.58 1.37 1.15 414 Appendix C-l.2.2 (continued). Mineral chemistry of feldspars in basaltic andesite from Parasitic Cones. Sample 427 427 427 427 427 427 428 Grain PI GM1 GM2 P2 P2 P2 PI Spot R C C R C R R SiC_ 56.56 57.19 57.36 57.78 53.71 57.46 48.65 AI2O3 27.44 26.84 26.74 26.55 29.42 26.65 32.68 FeO 0.28 0.41 0.40 0.37 0.27 0.41 0.58 MgO 0.04 0.03 0.04 0.03 0.04 0.03 0.04 CaO 9.04 8.58 8.38 7.82 11.17 7.95 14.95 Na20 5.88 6.10 6.33 6.55 5.00 6.59 2.88 K20 0.76 0.85 0.75 0.90 0.39 0.91 0.22 Total 100.51 100.85 100.59 100.42 100.85 100.71 101.13 Si 10.179 10.288 10.312 10.378 9.721 10.334 8.917 Al 5.822 5.692 5.667 5.622 6.278 5.651 7.062 Fe 0.042 0.062 0.060 0.056 0.041 0.062 0.089 Mg 0.011 0.008 0.011 0.008 0.011 0.008 0.011 Ca 1.743 1.654 1.614 1.505 2.166 1.532 2.936 Na 2.052 2.128 2.207 2.281 1.755 2.298 1.024 K 0.174 0.195 0.172 0.206 0.090 0.209 0.051 Total 20.023 20.027 20.043 20.056 20.062 20.094 20.090 An 43.91 41.59 40.43 37.70 54.01 37.93 73.20 Ab 51.69 53.51 55.26 57.14 43.75 56.90 25.52 Or 4.40 4.91 4.31 5.17 2.25 5.17 1.28 415 Appendix C-l.2.2 (continued). Mineral chemistry of feldspars in basaltic andesite from Parasitic Cones. Sample 428 428 428 428 428 428 Grain PI PI GM1 GM2 GM3 GM4 Spot C R C C C C Si02 49.69 50.11 48.65 47.32 65.31 65.99 AI2O3 31.91 31.78 32.56 33.55 20.37 18.79 FeO 0.59 0.46 0.77 0.61 0.54 0.59 MgO 0.06 0.04 0.04 0.04 0.03 0.03 CaO 14.23 14.10 14.77 15.94 1.27 1.02 Na20 3.32 3.32 3.02 2.40 4.98 5.59 K20 0.20 0.19 0.19 0.14 7.50 7.99 Total 101.01 100.70 100.37 100.72 99.75 99.67 Si 9.087 9.147 8.924 8.701 11.734 11.906 Al 6.880 6.839 7.041 7.273 4.315 3.997 Fe 0.090 0.070 0.118 0.094 0.081 0.089 Mg 0.016 0.011 0.011 0.011 0.008 0.008 Ca 2.788 2.758 2.903 3.140 0.244 0.197 Na 1.177 1.175 1.074 0.856 1.735 1.956 K 0.047 0.044 0.044 0.033 1.719 1.839 Total 20.085 20.044 20.115 20.108 19.836 19.992 An 69.50 69.34 72.19 77.95 6.61 4.94 Ab 29.34 29.55 26.71 21.24 46.91 48.99 Or 1.16 1.11 1.11 0.82 46.48 46.07 416 Appendix C-l.2.3. Mineral chemistry of feldspars in basaltic andesite from Young Ungaran. Sample 825 825 825 825 825 825 827 827 827 Grain PI PI PI GM1 GM2 GM3 GM1 PI PI Spot R C R C C C C R C SiC_ 52.99 55.27 53.24 46.97 53.88 49.17 52.12 57.37 54.97 AI2O3 30.04 29.14 29.97 33.64 29.34 32.12 30.32 27.42 28.78 FeO 0.45 0.36 0.46 0.58 0.45 0.69 0.31 0.21 0.35 MgO 0.03 0.03 0.03 0.04 0.03 0.05 0.03 0.03 0.03 CaO 11.93 10.53 11.63 16.49 11.42 14.85 12.60 8.63 10.31 Na20 4.15 4.13 4.23 2.16 4.41 2.88 4.34 5.70 5.12 K20 0.41 0.54 0.44 0.13 0.47 0.25 0.28 0.64 0.44 Total 99.68 99.11 99.81 99.43 97.71 99.15 99.07 100.23 99.67 Si 9.602 9.933 9.639 8.647 9.748 9.009 9.474 10.277 9.912 ! Al 6.418 6.174 6.397 7.301 6.258 6.938 6.497 5.791 6.118 Fe 0.068 0.054 0.070 0.089 0.068 0.106 0.047 0.031 0.053 Mg 0.008 0.008 0.008 0.011 0.008 0.014 0.008 0.008 0.008 Ca 2.316 2.028 2.256 3.253 2.214 2.915 2.454 1.657 1.992 Na 1.458 1.439 1.485 0.771 1.547 1.023 1.530 1.980 1.790 K 0.095 0.124 0.102 0.031 0.108 0.058 0.065 0.146 0.101 Total 19.965 19.760 19.957 20.103 19.951 20.063 20.075 19.89 19.974 An 59.87 56.47 58.71 80.23 57.21 72.94 60.61 43.79 51.30 Ab 37.69 40.08 38.64 19.02 39.98 25.60 37.78 52.34 46.10 Or 2.45 3.45 2.64 0.75 2.80 1.46 1.60 3.87 2.61 | 417 Appendix C-l.2.3 (continued). Mineral chemistry of feldspars in basaltic andesite from Young Ungaran. Sample 827 827 827 827 437 437 437 437 437 Grain GM2 GM3 P2 P2 PI PI PI GM1 GM2 Spot C C R C R C R C C Si02 77.21 56.69 57.34 58.19 48.25 51.22 48.95 51.99 51.93 AI2Q3 15.54 28.19 27.74 27.11 32.64 30.41 32.27 30.05 30.21 FeO 1.62 0.31 0.28 0.29 0.70 0.66 0.64 0.73 0.65 MgO 0.24 0.03 0.04 0.04 0.03 0.03 0.03 0.03 0.03 CaO 0.98 9.53 9.03 8.29 15.51 12.99 14.92 12.58 12.61 Na20 0.61 4.75 4.98 5.42 2.69 2.95 2.96 4.29 4.24 K20 3.80 0.50 0.59 0.66 0.18 1.74 0.22 0.33 0.33 Total 99.20 99.41 99.45 99.01 99.53 100.06 99.26 100.20 99.40 Si 13.165 10.153 10.256 10.392 8.864 9.382 8.974 9.473 9.458 Al 3.124 5.952 5.849 5.708 7.069 6.567 6.975 6.455 6.486 Fe 0.231 0.046 0.042 0.043 0.108 0.101 0.098 0.111 0.099 Mg 0.061 0.008 0.011 0.011 0.008 0.008 0.008 0.008 0.008 Ca 0.179 1.829 1.731 1.586 3.053 2.549 2.931 2.456 2.461 Na 0.202 1.650 1.727 1.877 0.958 1.048 1.052 1.516 1.497 K 0.827 0.114 0.135 0.150 0.042 0.407 0.051 0.077 0.077 Total 17.789 19.752 19.751 19.767 20.102 20.062 20.089 20.096 20.086 An 14.83 50.91 48.17 43.90 75.32 63.68 72,64 60.67 60.99 Ab 16.70 45.91 48.08 51.94 23.64 26.17 26.08 37.44 37.11 Or 68.47 3.18 3.75 4.16 1.04 10.16 1.28 1.81 1.90 418 Appendix C-l.3.1. Mineral chemistry of feldspars in andesite from Oldest Ungaran. Sample 930 930 930 930 930 930 930 930 Grain PI PI PI P2 P2 GM1 P3 P3 Spot R C R R C C M C Si02 43.36 43.78 43.51 46.14 46.52 45.39 44.71 44.24 AI2O3 36.12 35.98 35.84 33.60 33.89 34.83 34.99 35.07 FeO 0.58 0.52 0.58 1.42 0.72 0.66 0.71 0.61 MgO 0.02 0.04 0.04 0.48 0.06 0.04 0.04 0.04 CaO 18.97 18.70 19.12 16.17 16.53 17.49 18.06 18.64 Na20 0.91 0.93 0.85 1.98 2.09 1.48 1.40 1.29 K20 0.04 0.05 0.06 0.20 0.18 0.11 0.09 0.11 Total 100.72 101.61 99.45 101.06 101.37 101.76 100.33 99.99 Si 8.051 8.114 8.081 8.536 8.579 8.385 8.284 8.213 Al 7.907 7.862 7.848 7.328 7.368 7.585 7.643 7.676 Fe 0.090 0.081 0.090 0.220 0.111 0.102 0.110 0.095 Mg 0.006 0.011 0.011 0.132 0.016 0.011 0.011 0.011 Ca 3.774 3.714 3.805 3.205 3.266 3.462 3.585 3.708 Na 0.328 0.334 0.306 0.710 0.747 0.530 0.503 0.464 K 0.009 0.012 0.014 0.047 0.042 0.026 0.021 0.026 Total 20.165 20.128 20.155 20.178 20.129 20.101 20.157 20.193 An 91.80 91.48 92.24 80.89 80.53 86.16 87.24 88.32 Ab 7.97 8.23 7.42 17.92 18.43 13.19 12.24 11.06 Or 0.23 0.29 0.34 1.19 1.04 0.65 0.52 0.62 419 Appendix C-l.3.2 (continued). Mineral chemistry of feldspars in andesitefrom Oldes t Ungaran. Sample 924 924 924 924 Grain PI PI PI GM1 Spot R C R C Si02 50.60 52.04 53.09 53.82 AI2O3 31.25 30.20 29.69 29.02 FeO 0.51 0.53 0.38 0.47 MgO 0.05 0.06 0.03 0.02 CaO 13.10 12.04 11.41 10.86 Na20 4.18 4.73 5.03 5.32 K20 0.31 0.40 0.37 0.49 Total 100.76 101.41 100.63 101.36 Si 9.239 9.475 9.632 9.758 Al 6.727 6.482 6.350 6.203 Fe 0.078 0.081 0.058 0.071 Mg 0.014 0.016 0.008 0.005 Ca 2.563 2.349 2.218 2.110 Na 1.480 1.670 1.769 1.870 K 0.072 0.093 0.086 0.113 Total 20.173 20.166 20.121 20.13 An 62.28 57.13 54.46 Ab 35.96 40.61 43.44 Or 1.75 2.26 2.10 420 Appendix C-l.3.3 (continued). Mineral chemistry of feldspars in andesite from Parasitic Cones. Sample 424 424 424 424 424 424 429 Grain PI P2 P2 P2 P3 P3 PI Spot R C R M R C C Si02 51.40 55.61 54.53 54.82 55.94 54.53 54.40 AI2O3 30.59 27.91 28.32 28.43 27.73 28.65 28.97 FeO 0.52 0.32 0.64 0.39 0.25 0.28 0.34 MgO 0.03 0.02 0.04 0.05 0.02 0.02 0.09 CaO 12.89 9.83 10.48 10.13 9.50 10.61 10.84 Na20 4.25 5.71 5.55 5.57 5.78 5.37 4.90 K20 0.32 0.60 0.44 0.61 0.78 0.54 0.45 Total 100.05 99.97 100.99 100.97 100.73 100.38 101.49 Si 9.372 10.035 9.879 9.913 10.089 9.864 9.829 Al 6.575 5.938 6.049 6.061 5.896 6.100 6.171 Fe 0.079 0.048 0.097 0.059 0.038 0.042 0.051 Mg 0.008 0.005 0.011 0.013 0.005 0.005 0.024 Ca 2.518 1.901 2.034 1.963 1.836 2.056 2.099 Na 1.503 1.998 1.950 1.953 2.021 1.883 1.717 K 0.074 0.138 0.102 0.141 0.179 0.125 0.104 Total 20.129 20.063 20.122 20.103 20.064 20.085 19.995 An 61.49 47.08 49.79 48.39 45.48 50.59 53.55 Ab 36.69 49.49 47.72 48.15 50.07 46.34 43.80 Or 1.82 3.42 2.49 3.47 4.45 3.07 2.65 421 Appendix C-l.3.3 (continued). Mineral chemistry of feldspars in andesite from Parasitic Cones. Sample 429 429 429 429 429 429 429 Grain PI PI P2 P2 GM1 P3 P3 Spot M R C R C C R SiC_ 57.31 49.48 58.55 58.83 61.21 56.19 58.88 AI2O3 26.88 32.03 25.83 25.99 23.73 27.78 25.99 FeO 0.53 0.69 0.59 0.44 0.66 0.32 0.37 MgO 0.10 0.10 0.09 0.10 0.09 0.09 0.09 CaO 8.46 14.72 7.52 7.54 6.56 9.63 7.46 5.38 6.34 Na20 6.01 2.77 6.43 6.22 5.57 0.62 0.87 K20 0.72 0.22 0.99 0.87 2.17 Total 101.94 101.99 99.45 101.21 98.33 97.20 99.47 Si 10.297 9.052 10.506 10.529 10.950 10.111 10.534 Al 5.694 6.908 5.464 5.484 5.005 5.893 5.482 Fe 0.080 0.106 0.089 0.066 0.099 0.048 0.055 Mg 0.027 0.027 0.024 0.027 0.024 0.024 0.024 Ca 1.629 2.885 1.446 1.446 1.257 1.857 1.430 Na 2.094 0.983 2.237 2.158 1.932 1.877 2.199 K 0.165 0.051 0.227 0.199 0.495 0.142 0.199 Total 19.986 20.012 19.993 19.909 19.762 19.952 19.923 37.36 An 41.90 73.62 36.98 38.02 34.13 47.90 57.45 Ab 53.86 25.07 57.22 56.76 52.43 48.43 5.19 a 4.25 1.31 5.80 5.22 13.44 3.67 422 Appendix C-l.3.4 . Mineral chemistry of feldspars in andesite from Young Ungaran. Sample 320 320 320 320 320 320 320 320 Grain PI PI PI GM1 P2 P2 P3 P3 Spot R C R C R C R C Si02 57.40 56.88 54.29 49.09 55.07 54.83 51.94 45.84 AI2O3 28.56 27.23 28.99 32.08 28.41 28.51 30.21 34.13 FeO 0.29 0.29 0.24 0.56 0.39 0.36 0.50 0.57 MgO 0.02 0.02 0.02 0.08 0.02 0.02 0.04 0.04 CaO 9.61 8.71 10.71 14.83 PI 10.20 12.62 17.51 Na20 3.60 6.28 5.35 3.14 5.64 5.62 4.36 1.83 K20 0.52 0.59 0.40 0.22 0.47 0.46 0.33 0.09 Total 97.58 99.65 99.25 99.41 99.16 98.50 98.01 98.54 Si 10.222 10.227 9.815 8.998 9.944 9.908 9.458 8.471 Al 5.996 5.772 6.179 6.933 6.048 6.074 6.485 7.436 Fe 0.043 0.044 0.036 0.086 0.059 0.054 0.076 0.088 Mg 0.005 0.005 0.005 0.022 0.005 0.005 0.011 0.011 Ca 1.834 1.678 2.075 2.913 1.935 1.975 2.462 3.467 Na 1.243 2.189 1.876 1.116 1.975 1.969 1.539 0.656 K 0.118 0.135 0.092 0.051 0.108 0.106 0.077 0.021 Total 19.461 20.050 20.078 20.119 20.074 20.091 20.108 20.150 An 57.39 41.92 51.32 71.39 48.16 48.76 60.37 83.66 Ab 38.91 54.70 46.39 27.35 49.15 48.62 37.75 15.82 Or 3.70 3.38 2.28 1.26 2.69 2.62 1.88 0.51 423 Appendix C-l.3.4 (continued). Mineral chemistry of feldspars in andesitefrom Youn g Ungaran. Sample 323 323 323 323 323 323 323 323 Grain PI PI GM1 P2 P3 P3 P4 P5 Spot R C C C C R SiC_ 55.65 54.35 55.73 55.21 57.72 59.71 55.72 56.53 AI2O3 28.11 28.87 27.96 28.60 26.96 25.23 27.89 27.60 FeO 0.35 0.33 0.34 0.36 0.26 0.50 0.46 0.47 MgO 0.02 0.03 0.02 0.09 0.10 0.09 0.09 0.09 CaO 9.56 10.60 9.46 10.18 8.38 6.53 9.91 9.14 Na20 5.80 5.42 5.97 5.06 5.88 6.97 5.29 5.62 K20 0.51 0.40 0.52 0.50 0.71 0.96 0.54 0.55 Total 101.49 101.24 100.97 99.56 100.12 99.90 99.30 1100.9 0 Si 10.031 9.829 10.049 9.950 10.341 10.677 10.042 10.163 Al 5.974 6.155 5.943 6.076 5.694 5.319 5.949 5.850 Fe 0.053 0.050 0.051 0.054 0.039 0.075 0.069 0.071 Mg 0.005 0.008 0.005 0.024 0.027 0.024 0.024 0.024 Ca 1.846 2.054 1.828 1.966 1.609 1.251 1.914 1.761 Na 2.027 1.901 2.087 1.768 2.043 2.417 1.849 1.959 K 0.117 0.092 0.120 0.115 0.162 0.219 0.124 0.126 Total 20.053 20.089 20.083 19.953 19.915 19.982 19.971 19.954 An 46.27 50.76 45.30 51.07 42.18 32.19 49.24 45.78 50.94 Ab 50.80 46.96 51.73 45.94 53.56 62.18 47.57 Or 2.94 2.28 2.96 2.99 4.26 5.63 3.19 3.28 424 Appendix C-l.3.4 ontinued). Mineral of feldspars in from Young Ungaran. Sample 420 420 420 420 420 420 420 Grain PI PI P2 _P2 P2_ GM1 GM2 Spot C R C M R C C Si02 54.99 57.25 56.44 57.36 56.30 54.62 73.78 AI2O3 28.64 27.11 27.45 26.09 27.55 28.74 14.43 FeO 0.31 0.47 0.31 0.58 0.46 0.59 1.02 MgO 0.09 0.09 0.09 1.99 0.09 0.10 0.09 CaO 10.45 8.51 9.38 8.22 9.30 10.57 0.70 Na20 5.15 5.91 5.69 5.25 5.56 4.80 2.91 K20 0.37 0.96 0.64 0.51 0.75 0.59 7.06 Total 101.33 99.23 100.18 100.43 101.77 101.89 99.84 Si 9.917 10.278 10.158 10.281 10.140 9.871 12.962 Al 6.089 5.738 5.825 5.513 5.850 6.123 2.989 Fe 0.047 0.071 0.047 0.087 0.069 0.089 0.150 Mg 0.024 0.024 0.024 0.532 0.024 0.027 0.024 Ca 2.019 1.637 1.809 1.579 1.795 2.047 0.132 Na 1.801 2.057 1.986 1.825 1.942 1.682 0.991 K 0.085 0.151 0.147 0.117 0.172 0.136 1.582 Total 19.982 19.956 19.996 19.934 19.992 19.975 18.830 An 51.71 42.57 45.89 44.85 45.92 52.96 4.87 Ab 46.11 53.50 50.38 51.84 49.68 43.52 36.64 Or 2.18 3.93 3.73 3.31 4.41 3.52 58.49 425 Appendix C-1.3.4 (continued). Mineral of feldspars in andesitefrom Youn g Ungaran. Sample 440 440 440 440 440 440 440 Grain PI PI PI PI P2 P2 P2 Spot R C M R R C M Si02 57.45 53.09 58.00 57.52 56.03 56.42 56.47 AI2O3 26.87 29.79 26.88 26.95 29.19 27.91 27.61 FeO 0.28 0.37 0.28 0.27 0.28 0.28 0.26 MgO 0.03 0.03 0.04 0.03 0.03 0.03 0.03 CaO 8.23 11.57 7.98 8.17 8.79 9.41 8.86 Na20 6.52 4.84 6.09 6.44 5.05 5.41 6.21 K20 0.62 0.31 0.73 0.62 0.63 0.54 0.56 Total 100.27 99.68 98.52 99.50 99.05 98.70 99.69 Si 10.315 9.625 10.383 10.32 10.035 10.135 10.158 Al 5.688 6.367 5.673 5.70 6.163 5.91 5.855 Fe 0.042 0.056 0.042 0.041 0.042 0.042 0.039 Mg 0.008 0.008 0.011 0.008 0.008 0.008 0.008 Ca 1.583 2.248 1.531 1.571 1.687 1.811 1.708 Na 2.27 1.701 2.114 2.24 1.754 1.884 2.166 K 0.142 0.072 0.167 0.142 0.144 0.124 0.129 Total 20.048 20.077 19.921 20.022 19.833 19.914 20.063 An 39.63 55.90 40.16 39.73 47.06 47.42 42.67 Ab 56.81 42.32 55.46 56.68 48.93 49.34 54.12 Or 3.55 1.78 4.37 3.59 4.02 3.24 3.21 426 Appendix C-2.1.1. Mineral chemistry of clinopyroxenes in basalt from Oldest Ungaran. Sample 925 925 921 921 921 921 921 921 Grain PI PI PI PI PI GM1 P2 P3 Spot ~C~ R R C R C C C Si02 51.15 51.48 48.92 49.93 50.07 48.28 50.30 50.05 Ti02 0.47 0.52 0.82 0.51 0.47 1.13 0.57 0.72 AI2O3 3.32 3.31 4.17 3.13 3.04 4.95 4.12 4.52 n.d. n.d. 0.11 0.11 Cr203 0.12 0.10 n.d. n.d. FeO 7.88 7.78 8.84 8.90 8.93 9.13 8.49 8.78 MnO 0.16 0.30 0.25 0.29 0.31 0.27 0.22 0.20 MgO 13.67 13.99 14.30 14.72 14.63 13.85 14.06 13.36 CaO 21.98 22.08 22.29 22.10 22.14 21.96 21.99 22.15 Na20 1.26 0.43 0.36 0.39 0.37 0.37 0.13 0.14 Total 95.28 96.34 99.22 98.56 98.69 99.75 97.53 95.01 Si 1.884 1.907 1.812 1.848 1.854 1.792 1.868 1.863 AlN 0.116 0.093 0.182 0.137 0.133 0.208 0.132 0.137 Ti 0.013 0.014 0.023 0.014 0.013 0.032 0.016 0.020 A1VI 0.028 0.052 0.000 0.000 0.000 0.009 0.048 0.062 Cr 0.003 0.003 0.001 0.001 0.001 0.001 0.003 0.003 Fe3+ 0.149 0.039 0.161 0.135 0.132 0.161 0.059 0.041 Fe2+ 0.094 0.202 0.113 0.140 0.145 0.122 0.205 0.232 Mn 0.005 0.009 0.008 0.009 0.010 0.008 0.007 0.006 Mg 0.750 0.773 0.789 0.812 0.807 0.766 0.778 0.741 Ca 0.867 0.877 0.885 0.876 0.879 0.874 0.875 0.884 Na 0.090 0.031 0.026 0.028 0.027 0.027 0.009 0.010 Wo 50.52 47.13 49.30 47.69 47.75 49.38 46.92 47.45 En 43.71 41.54 43.96 44.20 43.83 43.28 41.72 39.77 Fs 5.77 11.34 6.74 8.11 8.42 7.34 11.37 12.78 427 Appendix C-2.1.2. Mineral chemistry of clinopyroxenes in basalt from Old Ungaran. Sample 918 918 918 918 918 918 Grain PI GM1 P2 P3 P4 P4 Spot R C C C C C SiOa 49.97 50.51 50.98 51.19 50.13 50.81 Ti02 0.78 0.69 0.42 0.54 0.61 0.56 AI2O3 3.93 3.45 3.74 3.16 4.94 3.39 0.11 0.11 0.11 Cr203 n.d. n.d. 0.11 FeO 8.56 7.96 7.53 8.07 8.49 8.12 MnO 0.34 0.29 0.23 0.28 0.30 0.24 MgO 14.05 14.51 14.00 14.20 13.45 14.10 CaO 21.84 22.08 22.77 22.13 21.71 22.54 0.31 0.26 0.13 Na20 0.49 0.46 0.21 Total 98.77 98.53 98.76 98.91 99.19 99.71 Si 1.851 1.867 1.889 1.898 1.862 1.887 Al™ 0.149 0.133 0.111 0.102 0.138 0.113 Ti 0.022 0.019 0.012 0.015 0.017 0.016 AlVI 0.023 0.018 0.052 0.036 0.079 0.035 Cr 0.001 0.001 0.003 0.003 0.003 0.003 Fe3+ 0.116 0.109 0.047 0.054 0.040 0.053 0.224 0.199 Fe2+ 0.149 0.137 0.186 0.196 Mn 0.011 0.009 0.007 0.009 0.009 0.008 Mg 0.776 0.799 0.773 0.785 0.745 0.780 Ca 0.867 0.875 0.904 0.879 0.864 0.897 0.009 Na 0.035 0.033 0.015 0.022 0.019 47.61 Wo 48.09 48.08 48.34 47.03 46.91 41.40 En 43.04 43.90 41.34 42.00 40.45 10.99 Fs 8.87 8.02 10.32 10.97 12.65 428 Appendix C-2.1.2 (continued). Mineral chemistry of clinopyroxenes in basaltfrom Old Ungaran. Sample 918 918 822 822 822 822 822 826 Grain P5 P5 PI PI P2 P3 P3 PI Spot C R C R R C R R SiC_ 53.23 50.28 51.53 51.42 51.83 51.89 51.32 51.56 Ti02 0.10 0.75 0.34 0.30 0.33 0.32 0.39 0.21 AI2O3 1.39 4.23 2.64 3.08 2.70 2.68 3.35 1.35 Cr203 0.11 0.10 0.11 0.10 0.10 0.11 0.10 n.d. FeO 7.97 8.71 8.80 8.56 8.37 8.93 8.56 9.69 MnO 0.30 0.24 0.41 0.52 0.45 0.55 0.41 0.99 MgO 14.31 13.52 14.12 14.15 14.34 13.99 13.94 14.64 CaO 22.28 21.77 21.92 21.60 21.75 21.39 21.80 21.13 Na20 0.30 0.39 0.13 0.27 0.13 0.13 0.13 0.38 Total 98.78 97.01 100.33 98.47 98.24 97.70 98.66 99.75 Si 1.976 1.869 1.918 1.910 1.926 1.934 1.909 1.919 Al™ 0.024 0.131 0.082 0.090 0.074 0.066 0.091 0.059 Ti 0.003 0.021 0.010 0.008 0.009 0.009 0.011 0.006 A1VI 0.037 0.054 0.034 0.044 0.044 0.052 0.056 0.000 Cr 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.001 Fe3+ 0.000 0.061 0.036 0.046 0.018 0.003 0.020 0.074 Fe2+ 0.247 0.210 0.238 0.220 0.242 0.275 0.247 0.228 Mn 0.009 0.008 0.013 0.016 0.014 0.017 0.013 0.031 Mg 0.792 0.749 0.783 0.783 0.794 0.777 0.773 0.812 Ca 0.886 0.867 0.874 0.860 0.866 0.854 0.869 0.843 0.022 Na 0.028 0.009 0.019 0.009 0.009 0.009 0.027 Wo 45.81 47.27 45.81 45.77 45.20 44.41 45.69 44.04 En 40.95 40.84 41.040 41.67 41.44 40.41 40.64 42.42 Fs 13.24 11.89 13.160 12.56 13.36 15.18 13.67 13.53 429 Appendix C-2.1.2 (continued). Mineral chemistry of clinopyroxenes in basaltfrom Old Ungaran. Sample 826 832 831 832 Grain PI PI P2 PI Spot C R C R Si02 51.23 50.67 51.16 50.66 TiC_ 0.25 0.61 0.60 0.59 AI2O3 1.73 3.21 2.96 3.30 O-2O3 n.d. 0.11 0.10 0.10 FeO 9.91 9.07 8.68 9.55 MnO 0.98 0.23 0.38 0.41 MgO 14.61 13.98 14.01 14.09 CaO 20.86 21.98 21.89 20.98 Na20 0.39 0.13 0.24 0.32 Total 100.09 98.67 97.37 97.92 Si 1.906 1.887 1.903 1.885 Al™ 0.076 0.113 0.097 0.115 Ti 0.007 0.017 0.017 0.017 AlVI 0.000 0.028 0.032 0.030 Cr 0.001 0.003 0.003 0.003 Fe3+ 0.089 0.057 0.046 0.073 Fe2+ 0.220 0.225 0.224 0.225 Mn 0.031 0.007 0.012 0.013 Mg 0.810 0.776 0.776 0.781 Ca 0.832 0.877 0.872 0.836 Na 0.028 0.009 0.017 0.023 Wo 43.95 46.53 46.28 45.07 En 42.79 41.17 41.19 42.10 Fs 13.26 12.31 12.53 12.83 430 Appendix C-2.1.3. chemistry clinopyroxenes basalt from Parasitic Cones. Sample 917 917 917 917 917 917 917 Grain GM1 PI PI P2 P2 P3 P3 Spot C R C R C R C Si02 50.97 44.48 46.79 48.07 47.56 46.05 52.44 Ti02 0.48 1.51 1.13 0.85 0.96 1.16 0.21 AI2O3 2.59 9.74 7.47 6.32 7.44 8.99 2.33 Cr203 n.d. n.d. n.d. n.d. 0.11 0.11 0.11 FeO 9.35 8.67 7.31 7.21 7.26 8.71 8.63 MnO 0.42 0.12 0.10 0.14 0.11 0.19 0.43 MgO 15.29 11.85 13.45 13.78 12.77 11.44 14.34 CaO 20.45 23.24 23.42 23.29 23.64 23.18 21.39 Na20 0.39 0.34 0.29 0.30 0.13 0.16 0.13 Total 98.99 99.54 99.62 99.32 98.88 99.72 97.45 Si 1.887 1.652 1.727 1.774 1.763 1.717 1.950 A.™ 0.113 0.348 0.273 0.226 0.237 0.283 0.050 Ti 0.013 0.042 0.031 0.024 0.027 0.033 0.006 AlW 0.000 0.078 0.052 0.048 0.088 0.113 0.052 Cr 0.001 0.001 0.001 0.001 0.003 0.003 0.003 Fe3+ 0.113 0.209 0.178 0.151 0.102 0.113 0.000 2 Fe + 0.176 0.061 0.048 0.071 0.123 0.159 0.268 Mn 0.013 0.004 0.003 0.004 0.003 0.006 0.014 Mg 0.844 0.656 0.740 0.758 0.705 0.636 0.795 Ca 0.811 0.925 0.926 0.921 0.939 0.926 0.852 Na 0.028 0.024 0.021 0.021 0.009 0.012 0.009 Wo 43.98 56.20 53.93 52.51 53.05 53.62 44.17 En 45.77 39.85 43.10 43.22 39.83 36.83 41.21 Fs 10.25 3.95 2.97 4.28 7.12 9.55 14.62 431 Appendix C-2.1.4. Mineral chemistry of clinopyroxenes in basalt from Young Ungaran. Sample 833 833 833 833 326 326 326 326 Grain PI PI P2 P3 PI PI GM1 P2 Spot C R C C R C C C SiC_ 52.28 52.68 52.60 52.35 47.77 52.11 51.85 52.73 Ti02 0.10 0.10 0.10 0.10 0.95 0.12 0.15 0.10 AI2O3 0.86 1.10 0.98 0.81 5.68 0.54 0.95 0.94 Cr203 0.10 0.10 0.10 0.11 n.d. n.d. n.d. 0.11 FeO 9.63 8.38 9.09 9.74 8.55 9.16 8.86 9.0 MnO 0.98 0.88 1.04 0.91 0.19 1.23 1.11 1.14 MgO 12.71 13.71 12.78 12.76 13.52 13.62 13.75 13.17 CaO 23.16 22.87 23.05 23.08 23.04 22.88 22.93 22.56 Na20 0.17 0.18 0.25 0.13 0.26 0.30 0.36 0.25 Total 95.29 96.93 96.86 97.90 100.11 100.50 99.32 98.59 Si 1.965 1.966 1.973 1.968 1.771 1.949 1.934 1.975 Al™ 0.035 0.034 0.027 0.032 0.229 0.024 0.042 0.025 Ti 0.003 0.003 0.003 0.003 0.026 0.003 0.004 0.003 AlVI 0.003 0.015 0.017 0.004 0.020 0.000 0.000 0.017 Cr 0.003 0.003 0.003 0.003 0.001 0.001 0.001 0.003 Fe3+ 0.036 0.024 0.020 0.028 0.173 0.038 0.058 0.017 Fe2+ 0.267 0.238 0.266 0.278 0.092 0.249 0.218 0.265 MN 0.031 0.028 0.033 0.029 0.006 0.039 0.035 0.036 Mg 0.712 0.763 0.715 0.715 0.747 0.759 0.764 0.735 Ca 0.933 0.915 0.927 0.930 0.915 0.917 0.917 0.906 Na 0.012 0.013 0.018 0.009 0.019 0.022 0.026 0.018 Wo 48.02 47.07 47.76 47.64 51.99 46.69 47.41 46.65 En 36.64 39.25 36.84 36.63 42.44 38.65 39.50 37.85 Fs 15.34 13.680 15.40 15.73 5.57 14.66 13.08 15.50 432 Appendix C-2.1.4 (continued). Mineral chemistry of clinopyroxenes in basaltfrom Youn g Ungaran. Sample 326 326 326 326 320 320 320 320 Grain P2 P3 P3 P4 PI PI PI P2 Spot R C R C R C R C SiC_ 53.26 52.60 51.73 48.21 51.62 51.82 53.02 48.71 Ti02 0.10 0.10 0.20 0.64 0.21 0.15 0.10 0.81 AI2O3 0.75 1.30 2.67 6.79 1.45 0.69 0.70 6.64 Cr203 0.11 0.10 0.11 0.11 n.d. n.d. 0.11 0.30 FeO 8.35 8.91 8.88 9.58 8.61 8.98 8.81 7.14 MnO 1.02 1.03 0.46 0.27 0.79 1.14 0.98 0.11 MgO 13.21 13.51 13.80 11.52 14.03 13.89 13.71 13.21 CaO 23.00 22.22 21.95 22.68 22.85 23.00 22.42 22.87 Na20 0.19 0.23 0.21 0.21 0.40 0.28 0.14 0.21 Total 98.29 99.30 97.42 98.74 98.17 98.47 99.51 99.25 Si 1.994 1.966 1.926 1.804 1.920 1.935 1.983 1.803 A.™ 0.006 0.034 0.074 0.196 0.064 0.030 0.017 0.197 Ti 0.003 0.003 0.006 0.018 0.006 0.004 0.003 0.023 AlVI 0.027 0.024 0.043 0.103 0.000 0.000 0.014 0.093 Cr 0.003 0.003 0.003 0.003 0.001 0.001 0.003 0.009 Fe3+ 0.000 0.018 0.031 0.069 0.079 0.041 0.004 0.065 2 Fe + 0.261 0.260 0.245 0.231 0.188 0.239 0.272 0.156 Mn 0.032 0.033 0.015 0.009 0.025 0.036 0.031 0.003 Mg 0.737 0.753 0.766 0.642 0.778 0.773 0.764 0.729 Ca 0.923 0.890 0.876 0.909 0.911 0.920 0.899 0.907 Na 0.014 0.017 0.015 0.015 0.029 0.020 0.010 0.015 Wo 47.26 45.97 46.06 50.75 47.90 46.75 45.73 50.53 En 37.74 38.89 40.27 35.85 40.90 39.28 38.86 40.61 Fs 15.00 15.130 13.670 13.400 11.200 13.970 15.410 8.860 433 Appendix C-2.1.4 (continued). Mineral chemistry of clinopyroxenes in basalt from Young Ungaran. Sample 438 438 438 438 418 418 418 418 Grain PI PI P2 P2 PI PI PI GM1 Spot C R C R R C R C SiO_ 52.87 50.81 52.48 49.36 49.34 49.58 50.19 49.34 T1O2 0.10 0.52 0.10 0.89 0.77 0.67 0.72 0.89 AI2O3 0.90 3.99 1.06 6.43 3.98 3.50 3.52 4.12 Cr203 0.11 0.11 0.11 0.10 n.d. n.d. n.d. n.d. FeO 8.63 9.21 9.03 9.12 8.92 8.82 8.52 8.53 MnO 1.06 0.63 1.12 0.33 0.40 0.28 0.33 0.33 MgO 13.29 12.63 13.01 11.61 13.53 13.86 14.10 13.52 CaO 22.91 21.81 22.94 21.72 22.61 22.84 22.17 22.84 Na20 0.13 0.27 0.14 0.43 0.42 0.41 0.41 0.39 Total 98.98 97.67 96.06 97.44 98.67 98.68 98.34 98.21 Si 1.980 1.900 1.969 1.845 1.833 1.840 1.861 1.833 A.™ 0.020 0.100 0.031 0.155 0.167 0.153 0.139 0.167 Ti 0.003 0.015 0.003 0.025 0.022 0.019 0.020 0.025 AlVI 0.020 0.076 0.015 0.129 0.008 0.000 0.015 0.013 Cr 0.003 0.003 0.003 0.003 0.001 0.001 0.001 0.001 Fe3+ 0.001 0.010 0.017 0.005 0.145 0.144 0.112 0.131 Fe2+ 0.269 0.278 0.266 0.281 0.132 0.130 0.152 0.134 Mn 0.034 0.020 0.036 0.010 0.013 0.009 0.010 0.010 Mg 0.742 0.704 0.727 0.647 0.749 0.767 0.779 0.748 Ca 0.919 0.874 0.922 0.870 0.900 0.908 0.881 0.909 Na 0.009 0.020 0.010 0.031 0.030 0.030 0.029 0.028 Wo 46.79 46.59 47.26 48.12 50.17 50.06 48.35 50.47 En 37.78 37.53 37.26 35.79 41.75 42.28 42.76 41.53 Fs 15.43 15.88 15.48 16.10 8.08 7.66 8.89 8.00 434 Appendix C-2.1.4 (continued). Mineral chemistry of clinopyroxenes in basalt from Young Ungaran. Sample 418 418 418 418 418 418 418 418 418 Grain P2 P2 P3 P3 P4 P4 P5 P5 GM2 Spot M R C R C R C R C S1O2 48.42 48.89 50.18 51.24 50.68 50.88 51.20 50.49 48.48 TiC_ 1.11 0.90 0.70 0.41 0.49 0.53 0.54 0.71 0.79 AI2O3 5.17 4.57 4.23 3.46 3.79 3.65 2.97 3.79 6.18 Cr203 0.05 n.d. 0.11 0.11 0.11 0.11 0.10 0.11 0.11 FeO 8.77 8.59 8.59 8.38 8.64 8.88 8.30 8.50 7.82 MnO 0.31 0.32 0.27 0.33 0.29 0.35 0.40 0.31 0.19 MgO 13.28 13.57 13.38 13.84 13.62 13.75 14.42 13.67 13.04 CaO 22.45 22.74 22.37 22.09 22.22 21.66 21.80 22.21 23.26 Na20 0.43 0.38 0.17 0.13 0.15 0.19 0.26 0.20 0.13 Total 98.76 97.79 100.22 99.27 98.63 99.82 98.18 99.50 99.20 Si 1.799 1.815 1.868 1.906 1.886 1.894 1.899 1.879 1.800 Al™ 0.201 0.185 0.132 0.094 0.114 0.106 0.101 0.121 0.200 Ti 0.031 0.025 0.020 0.011 0.014 0.015 0.015 0.020 0.022 AlVl 0.025 0.015 0.054 0.057 0.053 0.054 0.029 0.045 0.070 Cr 0.001 0.001 0.003 0.003 0.003 0.003 0.003 0.003 0.003 Fe3+ 0.143 0.147 0.047 0.020 0.041 0.033 0.057 0.048 0.092 Fe2+ 0.129 0.120 0.220 0.241 0.228 0.244 0.201 0.216 0.150 Mn 0.010 0.010 0.009 0.010 0.009 0.011 0.013 0.010 0.006 Mg 0.735 0.751 0.742 0.767 0.755 0.763 0.797 0.758 0.721 Ca 0.894 0.904 0.892 0.880 0.886 0.864 0.867 0.885 0.925 Na 0.031 0.027 0.012 0.009 0.011 0.014 0.019 0.014 0.009 Wo 50.57 50.64 47.88 46.36 47.18 45.91 46.17 47.35 51.33 En 41.57 42.07 39.83 40.41 40.20 40.54 42.44 40.56 40.01 Fs 7.86 7.28 12.29 13.22 12.62 13.55 11.40 12.09 8.66 Appendix C-2.2.1. Mineral chemistry of clinopyroxenes in basaltic andesitefrom Ol d Ungaran. Sample 820 820 820 820 922 Grain PI PI P2 P2 PI Spot R C R C R SiC_ 52.00 50.20 50.80 48.43 49.92 Ti02 0.38 0.65 0.46 0.74 0.58 AI2O3 2.24 3.70 3.19 5.49 3.28 Cr203 n.d. n.d. n.d. n.d. n.d. FeO 7.41 8.28 8.49 7.90 8.58 MnO 0.49 0.44 0.49 0.19 0.44 MgO 15.45 14.70 14.95 13.47 14.54 CaO 21.70 21.61 21.18 23.49 22.28 Na20 0.29 0.37 0.40 0.24 0.35 Total 102.79 101.49 101.58 99.94 98.28 Si 1.919 1.857 1.878 1.794 1.848 A.™ 0.081 0.143 0.122 0.206 0.143 Ti 0.011 0.018 0.013 0.021 0.016 A1VI 0.016 0.018 0.017 0.034 0.000 Cr 0.001 0.001 0.001 0.001 0.001 Fe3+ 0.064 0.115 0.107 0.147 0.135 Fe2+ 0.165 0.141 0.155 0.098 0.131 Mn 0.015 0.014 0.015 0.006 0.014 Mg 0.850 0.810 0.824 0.744 0.802 Ca 0.858 0.856 0.839 0.932 0.884 Na 0.021 0.027 0.029 0.017 0.025 Wo 45.44 47.01 45.77 52.36 48.28 En 45.02 44.48 44.95 41.80 43.80 Fs 9.53 8.51 9.27 5.84 7.92 436 Appendix C-2.2.1 (continued). Mineral chemistry of clinopyroxenes in basaltic andesite from Old Ungaran. Sample 922 922 922 922 922 Grain PI P2 P2 P2 GM1 Spot C C R C C Si02 50.76 49.90 47.31 48.86 51.09 TiC_ 0.49 0.56 0.83 0.71 0.33 AI2O3 2.55 3.49 6.76 5.16 2.31 G_03 n.d. n.d. 0.06 0.21 n.d. FeO 8.98 8.90 7.46 6.51 9.12 MnO 0.58 0.27 0.15 0.16 0.58 MgO 14.54 14.05 13.28 14.44 14.70 CaO 21.71 22.47 23.86 23.65 21.50 Na20 0.35 0.31 0.28 0.30 0.33 Total 98.65 98.85 99.55 99.23 98.86 Si 1.884 1.852 1.749 1.799 1.896 AlIV 0.112 0.148 0.251 0.201 0.101 Ti 0.014 0.016 0.023 0.020 0.009 AlVI 0.000 0.005 0.043 0.022 0.000 Cr 0.001 0.001 0.002 0.006 0.001 Fe3+ 0.108 0.132 0.180 0.155 0.105 Fe2+ 0.170 0.144 0.050 0.045 0.178 Mn 0.018 0.008 0.005 0.005 0.018 Mg 0,804 0.777 0.732 0.792 0.813 Ca 0.863 0.894 0.945 0.933 0.855 Na 0.025 0.022 0.020 0.021 0.024 Wo 46.52 49.04 54.56 52.56 45.87 En 43.34 42.62 42.26 44.62 43.62 Fs 10.13 8.34 3.18 2.82 10.52 437 Appendix C-2.2.2. Mineral chemistry of clinopyroxenes in basaltic andesite from Parasitic Cones. Sample 425 425 425 425 427 427 427 427 428 Grain PI PI GM1 GM2 PI PI P2 P2 GM1 Spot R C C C R C R C C S-O2 50.18 48.79 51.17 49.18 51.72 52.24 51.89 51.91 51.63 TiC_ 0.62 0.78 0.45 0.77 0.19 0.15 0.13 0.18 0.26 AI2O3 3.14 4.79 1.79 2.66 1.34 1.02 0.92 1.14 1.92 Cr203 n.d. n.d. n.d. 0.05 n.d. n.d. n.d. n.d. n.d. FeO 7.77 8.23 9.00 12.92 8.62 8.82 8.47 8.99 8.22 MnO 0.24 0.24 0.37 0.59 1.04 1.02 1.05 0.96 0.62 MgO 15.15 14.02 15.26 13.40 13.65 13.66 14.41 14.68 15.49 CaO 22.62 22.82 21.70 20.10 23.01 22.76 22.71 21.74 21.54 Na20 0.25 0.29 0.21 0.35 0.38 0.28 0.39 0.36 0.28 Total 100.14 99.60 99.45 97.87 99.17 99.04 100.16 99.87 100.08 Si 1.852 1.806 1.897 1.848 1.928 1.951 1.928 1.929 1.908 Ai™ 0.137 0.194 0.078 0.118 0.059 0.045 0.040 0.050 0.084 Ti 0.017 0.022 0.013 0.022 0.005 0.004 0.004 0.005 0.007 AlVl 0.000 0.015 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Cr 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 Fe3+ 0.119 0.155 0.067 0.098 0.075 0.056 0.060 0.065 0.088 Fe2+ 0.121 0.100 0.212 0.308 0.194 0.220 0.203 0.215 0.166 Mn 0.008 0.008 0.012 0.019 0.033 0.032 0.033 0.030 0.019 Mg 0.833 0.774 0.843 0.751 0.758 0.760 0.798 0.813 0.853 Ca 0.895 0.905 0.862 0.809 0.919 0.911 0.904 0.866 0.853 Na 0.018 0.021 0.015 0.026 0.027 0.020 0.028 0.026 0.020 Wo 48.20 50.64 44.69 42.87 48.27 47.37 46.65 45.01 45.11 En 44.86 43.31 43.70 39.80 39.81 39.52 41.18 42.26 45.11 Fs 6.95 6.04 11.61 17.33 11.92 13.10 12.18 12.73 9.78 438 Appendix C-2.2.3. Mineral chemistry of ies in basaltic andesite from Young Ungaran. Sample 825 827 827 827 827 827 437 437 437 Grain PI GM1 PI PI P2 P2 PI PI PI Spot C C R C R C R C R Si02 51.74 45.56 52.01 52.23 52.44 53.02 47.21 52.22 52.23 TO2 0.27 1.65 0.12 0.11 0.13 0.10 1.14 0.17 0.19 AI2O3 1.61 8.52 0.85 0.70 0.71 0.83 6.46 0.78 1.11 Cr203 n.d. n.d. n.d. n.d. n.d. 0.11 n.d. n.d. n.d. FeO 8.43 8.28 9.24 9.13 9.05 8.39 9.41 8.72 8.64 MnO 0.60 0.13 1.10 1.10 1.08 0.89 0.25 0.98 0.88 MgO 14.97 12.35 13.59 13.87 13.45 13.79 12.79 13.74 14.00 CaO 21.99 23.20 22.73 22.49 22.75 22.73 22.30 22.98 22.38 Na20 0.34 0.26 0.33 0.32 0.35 0.13 0.40 0.38 0.52 Total 98.60 98.27 99.93 99.00 99.15 100.07 99.24 99.93 97.57 Si 1.917 1.692 1.944 1.950 1.961 1.980 1.756 1.947 1.943 Al™ 0.070 0.308 0.037 0.031 .031 .020 0.244 0.034 0.049 Ti .008 0.046 0.003 0.003 0.004 0.003 0.032 0.005 0.005 AlVl 0.000 0.066 0.000 0.000 0.004 0.017 0.040 0.000 0.000 Cr 0.001 0.001 0.001 0.001 0.000 0.003 0.001 0.001 0.001 Fe3+ 0.079 0.167 0.053 0.047 0.001 0.003 0.168 0.051 0.074 Fe2+ 0.183 0.090 0.235 0.238 0.048 0.259 0.125 0.221 0.194 Mn 0.019 0.004 0.035 0.035 0.034 0.028 0.008 0.031 0.028 Mg 0.827 0.684 0.757 0.772 0.749 0.768 0.709 0.764 0.776 Ca 0.873 0.923 0.910 0.900 0.911 0.910 0.889 0.918 0.892 Na .024 0.019 0.024 0.023 0.025 0.009 0.029 0.027 0.038 Wo 45.90 54.26 46.98 46.27 47.23 46.31 51.36 47.47 47.20 En 43.48 40.21 39.08 39.69 38.83 39.08 40.96 39.50 41.06 Fs 10.62 5.53 13.94 14.04 13.95 14.61 7.68 13.03 11.75 439 Appendix C-2.3.1. Mineral chemistry of clinopyroxenes in andesite from Oldest Ungaran. Sample 930 930 930 930 Grain PI P2 P2 P2 Spot R R C R Si02 49.71 49.06 49.71 49.37 T1O2 0.72 0.83 0.71 0.88 AI2O3 3.81 4.60 3.56 4.13 Cr203 n.d. n.d. n.d. n.d. FeO 7.93 8.33 8.10 8.29 MnO 0.23 0.28 0.27 0.26 MgO 14.82 14.36 15.18 14.59 CaO 22.42 21.99 22.00 22.08 Na20 0.33 0.51 0.43 0.36 Total 100.68 99.32 99.80 100.34 Si 1.835 1.812 1.833 1.825 Ai™ 0.165 0.188 0.155 0.175 Ti 0.020 0.023 0.020 0.024 AlVI 0.001 0.012 0.000 0.005 Cr 0.010 0.001 0.001 0.001 Fe3+ 0.146 0.165 0.145 0.145 Fe2+ 0.098 0.093 0.105 0.111 Mn 0.007 0.009 0.008 0.008 Mg 0.815 0.790 0.834 0.804 Ca 0.887 0.870 0.869 0.875 Na 0.024 0.037 0.031 0.026 Total 4.018 4.021 4.021 4.018 Wo 49.09 49.38 47.85 48.67 En 45.10 44.84 45.93 44.72 Fs 5.81 5.79 6.22 6.62 440 Appendix C-2.3.2. Mineral chemistry of clinopyroxenes in andesite from Old Ungaran. Sample 924 924 924 924 924 924 Grain PI PI PI P2 P2 GM1 Spot R C R R C C Si02 51.72 50.41 51.23 51.43 51.25 51.09 Ti02 0.31 0.42 0.33 0.32 0.31 0.34 AI2O3 2.16 2.68 1.73 1.66 2.09 1.99 Cr203 n.d. n.d. n.d. n.d. n.d. n.d. FeO 8.39 9.46 8.70 8.83 8.85 9.14 MnO 0.69 0.68 0.70 0.70 0.62 0.67 MgO 15.01 14.71 15.62 15.80 15.35 14.98 CaO 21.04 21.20 21.27 20.85 21.08 21.32 Na20 0.64 0.39 0.38 0.37 0.41 0.43 Total 98.27 99.70 100.10 99.99 100.36 100.19 Si 1.910 1.871 1.893 1.901 1.895 1.893 A.™ 0.090 0.117 0.075 0.072 0.091 0.087 Ti 0.009 0.012 0.009 0.009 0.009 0.009 A1VI 0.005 0.000 0.000 0.000 0.000 0.000 Cr 0.001 0.001 0.001 0.001 0.001 0.001 Fe3+ 0.112 0.121 0.083 0.080 0.102 0.098 Fe2+ 0.147 0.173 0.186 0.193 0.172 0.186 Mn 0.022 0.021 0.022 0.022 0.019 0.021 Mg 0.826 0.813 0.860 0.870 0.846 0.827 Ca 0.833 0.843 0.842 0.826 0.835 0.847 Na 0.046 0.028 0.027 0.027 0.029 0.031 Total 4.014 4.019 4.023 4.020 4.016 4.018 Wo 45.57 45.57 44.08 43.22 44.60 45.03 En 45.19 43.95 45.03 45.53 45.19 43.97 Fs 9.25 10.49 10.89 11.25 10.20 11.00 441 Appendix C-2.3.3. Mineral chemistry of clinopyroxenes in andesitefrom Parasitic Cones. Sample 424 424 424 424 424 429 Grain PI PI P2 P2 P2 PI Spot R C R C R C Si02 47.80 49.19 51.32 51.49 51.60 48.10 T1O2 1.00 0.66 0.16 0.12 0.16 1.03 AI2O3 5.85 4.01 1.29 0.87 1.29 7.08 Cr203 n.d. n.d. 0.03 n.d. n.d. 0.11 FeO 8.23 8.40 10.69 10.80 9.91 8.12 MnO 0.16 0.33 0.91 1.08 0.94 0.13 MgO 13.54 13.60 12.92 12.94 13.63 12.23 CaO 23.09 23.39 22.34 22.33 22.06 23.05 Na20 0.29 0.38 0.34 0.33 0.37 0.16 Total 100.86 100.26 99.15 99.49 99.88 99.36 Si 1.771 1.825 1.927 1.935 1.929 1.791 A.™ 0.229 0.175 0.057 0.039 0.057 0.209 Ti 0.028 0.018 0.005 0.003 0.004 0.029 AlVi 0.026 0.000 0.000 0.000 0.000 0.101 Cr 0.001 0.001 0.001 0.001 0.001 0.003 Fe3+ 0.167 0.164 0.072 0.055 0.073 0.057 Fe2+ 0.088 0.097 0.264 0.285 0.236 0.194 Mn 0.005 0.010 0.029 0.034 0.030 0.004 Mg 0.748 0.752 0.723 0.725 0.759 0.679 Ca 0.916 0.930 0.899 0.899 0.883 0.919 Na 0.021 0.027 0.025 0.024 0.027 0.012 Total 4.021 4.021 4.014 4.019 4.013 4.007 52.13 51.98 46.95 46.27 46.28 51.17 42.57 42.03 37.75 37.31 39.78 37.81 5.29 5.98 15.30 16.42 13.94 11.02 442 Appendix C-2.3.4. Mineral chemistry of clinopyroxenes in andesite from Young Ungaran. Sample 320 320 323 323 323 Grain PI PI PI PI P2 Spot R C C R C Si02 51.55 51.50 51.13 51.48 52.81 TO2 0.20 0.19 0.32 0.17 0.10 AI2O3 1.16 1.25 1.83 1.14 1.38 Cr203 n.d. n.d. n.d. n.d. 0.11 FeO 9.18 9.18 8.63 9.70 9.21 MnO 1.02 0.95 0.68 0.87 0.76 MgO 13.58 13.34 14.32 13.51 13.44 CaO 22.83 23.18 22.69 22.69 21.77 Na20 0.44 0.37 0.36 0.42 0.41 Total 98.56 98.49 99.82 100.55 96.28 Si 1.924 1.924 1.899 1.923 1.972 AlIV 0.051 0.055 0.080 0.050 0.028 Ti 0.006 0.005 0.009 0.005 0.003 AlVI 0.000 0.000 0.000 0.000 0.033 Cr 0.001 0.001 0.001 0.001 0.003 3+ Fe 0.070 0.070 0.087 0.070 0.015 2+ Fe 0.216 0.217 0.181 0.233 0.272 Mn 0.032 0.030 0.021 0.028 0.024 Mg 0.755 0.743 0.793 0.752 0.748 Ca 0.913 0.928 0.903 0.908 0.871 Na 0.032 0.027 0.026 0.030 0.030 Total 4.019 4.016 4.016 4.020 4.002 Wo 47.65 48.38 47.58 47.27 45.48 En 39.41 38.74 41.78 39.15 39.06 Fs 12.94 12.88 10.64 13.59 15.46 443 Appendix C-2.3.4 (continued). Mineral chemistry of clinopyroxenes in andesite from Young Ungaran. Sample 323 420 420 440 440 440 Grain P2 PI PI PI PI GM1 Spot C C R R C C SiC_ 52.92 52.57 52.86 51.93 52.04 52.06 T1O2 0.10 0.12 0.10 0.17 0.21 0.35 AI2O3 1.56 1.46 1.69 1.24 1.27 1.31 Cr203 0.11 0.11 0.11 n.d. n.d. n.d. FeO 9.08 9.12 8.16 8.95 8.34 8.61 MnO 0.79 0.90 0.80 0.99 0.97 1.00 MgO 13.07 12.50 13.39 13.68 14.13 14.00 CaO 22.11 22.91 22.76 22.62 22.60 22.39 Na20 0.24 0.30 0.13 0.37 0.40 0.24 Total 98.54 97.03 98.68 99.11 99.10 99.34 Si 1.982 1.972 1.974 1.937 1.935 1.941 Ai™ 0.018 0.028 0.026 0.055 0.056 0.058 Ti 0.003 0.003 0.003 0.005 0.006 0.010 AlVI 0.051 0.037 0.048 0.000 0.000 0.000 Cr 0.003 0.003 0.003 0.001 0.001 0.001 Fe3+ 0.000 0.003 0.000 0.071 0.072 0.054 Fe2+ 0.284 0.284 0.255 0.209 0.188 0.214 Mn 0.025 0.029 0.025 0.031 0.031 0.032 Mg 0.729 0.699 0.745 0.761 0.783 0.778 Ca 0.887 0.921 0.911 0.904 0.900 0.895 Na 0.017 0.022 0.009 0.027 0.029 0.017 Total 3.992 4.000 3.993 4.011 4.011 4.007 Wo 46.05 47.65 47.05 47.14 47.03 46.21 En 37.88 36.16 38.51 39.65 40.89 40.18 Fs 16.08 16.19 14.44 13.22 12.08 13.62 444 CN i-H oo ON CN so oo CN CN CO oo SO T3 OO © to O -d CO rr ON I-H CN u © O cC ON to' vd CO IO* to to ON OO d ©' d d ON CO ON d rT CO vo OO & ON rt CO ON WO CO o oo ON 4—• -d T3 oo r-H r-» CO © oo vq oo CN T-H oo vq t-; rT 13 o rf CO d NO ON in ON d rf to rf d d CO rT ON ON rT in _ o to CN rH to CN to rT CN OO *d -d to 00 •d TJ T-H oo ON © OO WO r—< o rr Pi i—i X OH I-H r-* ©' © rf ON' CS od ON d rf d d rT o r- ON co rT ON UJ UH T-H •o CN to CN to oo rT ON CN r-H o rT ON CN -d CO o oo i-H CN OO to CN u o © CO p ON od d rf d d NO ON d d d rT ON to* ON CO to Xi CJ r^ i—i CO CN CN CN o o NO rT rT rH ON i-H "d r—* ON to CO o CN o vq oo _ PH © d to d IO* © CN* d to* CoN od ON rf ON u ON ON rT CO CO to NO CN o ON CO oo rH t*- oo to co NO © CO CO T3 oo I CN vq rr to CO cs KC Pi o to NO CN* ON d d © d d to* r-" ON CO* U ON CO ON CO r-H "J3 x a ro "o. C 4-* 1 T1 '„ c? O 13 3 6 13 PH' I-i O O O c co O- •i-H «rH 9, co co H PH 8 Pi BH lu UJ o co S 1 ZJ OH 3 O, < 445 «o CN to 00 O I-H to CN oo oo o to NO o CN to TJ CO CO © CO vq CN ON CN CN r- PH vd i—i d rf © i-H © rf wo rf ON od CO u d 00 ON to CO ON oo CN r» oo CN IO r- CN ON CN T-H TJ ON co TJ o o C-; TJ co rT rr rT IO r? PH u d T-H rf d NO ©* rH d to 1—1 ON ON d r~ ON rT co ON CO NO oo oo i-H to CO rH oo to CO ro r- T-H o IO oq TJ ON oo rt TJ t> o o ON to o CN* 1-H PH © r-" d © © CN* d rf CN rf ON CN ON oo ON to CO ON CN T-H r^ r- CN rt o to 00 r» t> rt vo CO CN CN CO CO T—1 rt co TJ* oq rt to O o ON u © CO* © i-* © © © CO* © CO ON © d oo ON SO CO ON OO o © o © 00 CN © so »o >o r- NO CJ © T-H rH •d CO NO CN rH r-; rT oo vq r-- oCNo § rf CN* J> © r-H © to ON T-H ON T-H o d 1-H d t> ON CO rT ON rT OO rt r- CO rH VO r- NO 1—1 © rT CO NO T3 ON CO © to t-» ON vq CN o rT CN o r-; S O d d rf d r^ © T-H © WO CO* od d CO OO rH r» ON rT CO o co o l-H 1 a CO 3 CO T-H co o Q 13 13 PH' '_ o 5 # CS O 9a 13 o o 4—i CO Q 15 1a o. • rH E2 lu r D CO p 3 0 HH ri J? lu E2 CO a CO s a 8 pi 446 to CO OO r- ON CN to rT O OO ,_, TJ CO © © !-H O CO r-H CO 1-H CN oo oq r-; PH pi d od CO* © © r-H © rf ON* NO ON to* 60 rT oo ON rT CO ON CN C 3 to CN CU o o CO o o CN OO rt ON OO to O to rt o CO ON i-H OO wo r-; TJ WO © o ON rt © CO* © d d to CO* ON ON* rf - ON rT CO ON rO in UJ T3 O ON oo CO ON oo I-H oo o CO OO CO I-H to •-H NO ON ON ON C-; • ^H •o , TJ NO wo •d t-; 13 CN PH Pi CN CO r-" T-H to* r-H ON* ON* NO d d d d ON CO ON CO in rt r^ rt J-J in OJ o CO o ON to CN rT ON © IO NO © r- © © NO © © oo rT ON i> IO TJ CN vq rr r» o PH u d r-* rf d ON' © CN* d rf ON rf ON CO* o OO t-- ON rt CO ON CN _ o CO CO to rr ro to ON r- o O t^- O © 1-H t~~; to t^- TJ CN CN t^ OO CN o o o oo PH Pi d t-* rf d ON d CN* d rf ON to* ON CO* oo ON rT CO ON CN • I-H S o r- to © oo o CN © CO NO r-; OO ON •3 CN I-H OO u © © CN* ON © to* WO* ON* I—I rH d d oo* _ o r-~ ON rT ro ON CO c CN oo o © rT ON CO CN o rT f- ON T-H i—t ,— I-H CO NO I-H i-H CO ON I CN o ! TJ vq o oq u I-H U ON © rr CN iZ © d to* ON T-H ON i-H 1—1 d ON ON •>S s r- 1 ro rT rt c3 T3 a ro ro 3O ro C "o- c 13 PH* UJ O O Q 13 .1-1s & o Q> Q 1 o o 4—> •a r*> DH co o. CO HH E2 oP co o p 32> 6 6 PcHs lu .2 OH CO f Pi 13 < 1 447 E o £ 4uH • —* to rs ON I-H CN T-H r~- CO to in -d CN ON CN HJ © to CO oq rt CN vq rT ON TJ CO o CO to' CN* PU © C-* CN* © © CN od C rT d ON CO CN „ 00 >o ON c> 4-» 1tn3 © T-H rt wo rt CO ON o O ON rt i-H JOa ON T-H p I-H CN CN vq © ON rT rT CO c CN u IO* CO ON od • • rH CU © rf CO © ro © I-H in oo © oo ON to ro ON U TJ • i-H X o ON to CO I-H rT CN CO CO NO CO WO CO .<—• to T-H rt CN TJ* tO so ON T-H vq ON r-; H i-H oo to* rT •ca OO TJ ON © I-H rT © rt ^•H O oq oo NO o CN to* ON ON 1-H PH © © 1-H © © © vd \—o' u d d ON ro ON CO CN rt 1-H 00 rT CO U '3 X . T3 r3 4> s o PH' OH DO •a o o 3 CS O CO OH G o o to to ON O rT o ON o CO rT © to CJ T-H CN o NO NO vq © CN I—I r- CN © I—H ON i-H © rf od ON vd CN rT © d ON ro ON rt CO WO o rT to ro OO rT oo rt o 00 00 T-H rT © CO © O rT vq o CO o ro r-H oo CN cu CJ © CN l-H ON rH ©' rf rf ON ON* to' rT T-H d d ON rT CO ON CO oo OO OO to CO VO oo rT r- I—H oo rT TJ to oq TJ t> oo rT i-H O CN ON rT CN PH* CJ d r-* CN d CN* © rf CN CO ON* CN ON d d ON to CO ON CN oo NO CN © to ON oo rt ON - o NO rt © oo OO © CN t> CN TJ © i-H ON rT CN ri © od CN ©' r—i © d to ON ON* vd ON u oo ON rT ro ON CN o ON i-H © o to © © o rT CN ON OO rT T—H CO s V © vq © vq IO CN CO P-; to i-H CN ON © d ro © od © CN* © to* to" © o r^ ON rT CO CO i-H o r-H 00 SO CO CN WO O NO rT OO © TJ ro to O rr IO CO TJ CO to i-H oo CO O to CU d T-H rf d © CN* to* CN od ON rf ON T-H d d r-» ON rT ro ON CO © © to oo oo © © r-- ON CO rT r~- CO © I-H CN CN © NO © CN oo CN rT CO CO Pi i-H cu © rf d © CN* to od ON rf ON l-H d d r- ON *_ g CO ON CO a ro ro O to c 4—* "o. o Q 3 13 O 13 PH' •a 6 6 9,o o CO 6 t-H O- • ^H "i-H PH 18 O cS PH co H £ D cd o CO 3 o P 4/ CO Pi vu 449 oo OO CN T-H CN © © OO © rT I-H oo S © ON ON ON to d NO vq ro .rOH u © o t~~; © <+H © t> © © rf © d d wo' d od ©' rf (1) 5 o oo ON to ro o CN •l-H in TJ i-H ON CO CO o CU u r-* CN* © CN rf NO ON" ro' PH d OO d d d ON dWO CO ON CN HH 5 o £ tn vo NO rt r~ to ON ro wo NO o '3 © CN © •o IO WO TJ* CO wo © C4 *d T-H _ OH CN* © ON* © © d rf CO* © ON* wo J! ON ON CO O 5 d rt rT 13 DHJ c CN oo to CO © T-H rT o WO oo r- OO o OO CO ON CO CO § o i-H rt CN rt © oo co oq wo CN PH CJ © © CO* © rf T-H T-H CN* rf CO* wo* od CN /"-\ T-H TJ rt r- ON rt CO ON CO 3_ •s C OO NO r^ o to CO W, I-H CN oo rr © CO i-H TJ oo © ON oo oo © Co) CN Pi o r^ r>; vq wo r- w PH © r^ 1-H d CO* © © © rf rH vd ON CO CO CO 00 ON WN. CO ON CN CO U 1 i 9 34H c 13 4—- PH* OH 60 6 Q 13 <5 13 0) 1 •a CS o 9a O o OH O S 8 Q 4^ co fi p* 1C3J < D CO CO P 3 S PH % S t2 Pi PH PH £ D 6 £ a o 450 Appendix C-4.1. Mineral chemistry of amphiboles in basalt from Ungaran. Sample 929 929 929 929 822 822 917 Grain PI PI P2 P2 PI PI PI Spot R C R M C R R Si02 39.70 37.75 38.34 39.95 40.86 41.88 40.73 TO2 2.81 2.96 2.65 2.86 3.19 3.10 2.62 AI2O3 12.26 12.08 12.03 12.50 12.58 12.44 12.54 Cr203 0.10 0.10 0.10 0.10 0.10 0.10 0.04 FeO* 11.83 11.42 11.25 11.40 12.13 12.32 13.21 MnO 0.25 0.34 0.18 0.19 0.22 0.28 0.32 MgO 12.08 11.90 11.29 12.63 13.10 13.45 13.03 CaO 11.08 10.83 10.79 11.45 11.65 11.84 11.10 Na20 2.76 2.60 3.03 2.48 2.02 2.10 2.44 K20 1.24 1.23 1.29 1.22 1.24 1.22 1.21 Total 94.00 91.12 90.85 94.67 97.00 98.62 97.20 Si 6.111 5.994 6.155 6.079 6.035 6.080 6.000 A.™ 1.889 2.006 1.845 1.921 1.965 1.920 2.000 Ti 0.325 0.353 0.320 0.327 0.354 0.338 0.290 AlVI 0.336 0.256 0.431 0.321 0.225 0.210 0.177 Cr 0.012 0.013 0.013 0.012 0.012 0.011 0.005 Fe3+ 0.163 0.278 0.219 0.481 0.481 0.735 Fe2+ 1.360 1.239 1.510 1.232 1.017 1.015 0.892 Mn 0.033 0.046 0.024 0.024 0.028 0.034 0.040 Mg 2.771 2.816 2.701 2.864 2.883 2.910 2.860 Ca 1.834 1.855 1.850 1.876 1.865 1.863 1.783 (Na)B 0.166 0.145 0.150 0.124 0.135 0.137 0.217 (Na)A 0.661 0.660 0.790 0.612 0.450 0.461 0.493 K 0.244 0.251 0.263 0.238 0.236 0.229 0.231 451 Appendix C-4.1 (continued). Mineral chemistry of amphiboles in basalt from Ungaran. Sample 917 326 326 326 438 438 438 Grain PI PI PI P2 PI P2 P2 Spot C C R C C C C SiO_ 39.54 38.00 40.15 39.27 36.89 44.92 45.77 Ti02 2.86 2.16 2.41 2.56 4.62 2.16 2.09 AI2O3 12.08 14.89 14.74 14.11 14.46 13.16 13.49 Cr203 0.04 0.04 0.04 0.04 0.11 0.10 0.10 FeO* 12.70 14.39 11.93 11.61 15.11 13.31 13.04 MnO 0.28 0.17 0.14 0.14 0.19 0.37 0.10 MgO 12.67 11.74 14.43 13.84 13.92 13.29 13.09 CaO 11.17 12.32 12.02 12.17 12.08 12.58 13.59 Na20 2.29 2.32 2.43 2.34 1.81 2.22 2.65 K20 1.16 1.16 1.14 1.04 0.94 1.09 0.39 Total 94.83 97.15 99.40 97.06 94.64 98.10 94.02 Si 5.998 5.686 5.737 5.780 5.268 6.253 6.342 Al™ 2.002 2.314 2.263 2.220 2.434 1.747 1.658 Ti 0.326 0.243 0.259 0.283 0.496 0.226 0.218 AlVI 0.158 0.312 0.221 0.229 0.413 0.545 Cr 0.005 0.005 0.005 0.005 0.012 0.011 0.011 Fe3+ 0.598 0.608 0.865 0.647 0.910 0.304 Fe2+ 1.014 1.192 0.561 0.782 0.895 1.245 1.511 Mn 0.036 0.022 0.017 0.017 0.023 0.044 0.012 Mg 2.864 2.618 3.073 3.036 2.962 2.757 2.703 Ca 1.842 2.000 1.880 1.950 1.917 1.890 2.000 0.120 0.050 0.083 0.110 (Na)B 0.158 0.567 0.628 0.437 0.493 0.710 (Na)A 0.525 0.683 K 0.228 0.225 0.212 0.198 0.178 0.195 0.069 452 Appendix C-4.1 (continued). Mineral chemistry of amphiboles in basalt from Ungaran. Sample 320 320 320 320 320 320 320 Grain PI P2 P3 P4 P4 P5 P5 Spot C C C C R C R Si02 38.82 39.82 38.52 39.86 40.77 41.72 37.67 TO2 2.17 2.21 2.46 2.06 2.18 2.02 1.61 AI2O3 14.35 13.19 13.84 14.88 13.96 13.78 10.06 &2O3 0.05 0.06 0.04 0.10 0.12 0.10 0.10 FeO* 10.18 10.12 11.62 11.14 10.20 9.80 12.97 MnO 0.11 0.10 0.14 0.15 0.14 0.10 0.60 MgO 14.53 15.10 13.85 13.34 14.55 15.10 10.86 CaO 12.51 12.19 12.31 12.28 12.19 12.28 11.98 Na20 2.26 2.21 2.21 2.08 2.17 2.02 1.56 K20 1.25 1.14 1.10 1.13 1.12 1.21 0.90 Total 96.25 96.13 96.86 96.91 97.40 97.94 88.20 Si 5.756 5.874 5.743 5.865 5.935 6.003 6.249 Al™ 2.244 2.126 2.257 2.135 2.065 1.997 1.751 Ti 0.242 0.245 0.276 0.228 0.239 0.219 0.201 AlVl 0.265 0.167 0.176 0.446 0.331 0.341 0.217 Cr 0.006 0.007 0.005 0.012 0.014 0.011 0.013 3+ Fe 0.596 0.689 0.670 0.500 0.569 0.583 0.437 2+ Fe 0.666 0.559 0.779 0.871 0.673 0.596 1.363 Mn 0.014 0.012 0.018 0.019 0.017 0.012 0.084 Mg 3.211 3.319 3.077 2.925 3.157 3.238 2.685 Ca 2.000 1.959 1.999 1.959 1.927 1.920 2.000 (Na)B 0.041 0.001 0.041 0.073 0.080 (Na)A 0.659 0.602 0.648 0.56 0.548 0.491 0.504 K 0.240 0.218 0.213 0.215 0.211 0.225 0.191 453 Appendix C-4.2. Mineral chemistry of amphiboles in basaltic andesite from Ungaran. Sample 922 922 428 428 825 827 Grain PI PI PI PI PI PI Spot R C R C C C SiO_ 38.77 39.20 39.70 40.18 36.38 39.04 Ti02 2.42 2.06 1.73 1.67 2.27 2.59 AI2O3 14.18 14.78 14.02 13.98 9.90 14.79 €r203 0.04 0.04 0.04 0.04 0.07 0.04 FeO* 12.01 10.67 13.36 13.39 11.78 11.79 MnO 0.13 0.08 0.31 0.26 0.30 0.12 MgO 13.42 13.86 12.85 13.36 12.02 13.45 CaO 12.64 12.73 11.90 11.95 11.15 12.20 Na20 2.17 2.09 2.25 2.37 2.13 2.18 jc2o 1.34 1.57 1.02 1.03 1.20 1.25 Total 97.13 97.04 97.15 98.18 87.20 97.46 Si 5.761 5.801 5.855 5.851 6.076 5.737 Al™ 2.239 2.199 2.145 2.149 1.924 2.263 Ti 0.270 0.229 0.192 0.183 0.285 0.286 A1VI 0.244 0.379 0.293 0.251 0.026 0.299 Cr 0.005 0.005 0.005 0.005 0.009 0.005 Fe3+ 0.564 0.457 0.784 0.848 0.374 0.622 Fe2+ 0.928 0.863 0.864 0.783 1.271 0.827 Mn 0.016 0.010 0.039 0.032 0.042 0.015 Mg 2.972 3.057 2.824 2.899 2.992 2.946 Ca 2.000 2.000 1.917 1.903 2.000 1.950 0.083 0.097 0.050 (Na)B 0.572 0.586 0.696 0.581 (Na)A 0.633 0.605 K 0.257 0.299 0.196 0.195 0.258 0.238 454 Appendix C-4.3. Mineral chemistry of amphiboles in andesite from Ungaran. Sample 924 924 424 424 424 429 429 Grain PI PI PI PI PI PI PI Spot R C R C M C R Si02 41.57 41.66 39.44 38.93 38.71 39.28 41.07 TO2 2.76 2.80 2.99 3.09 3.03 2.70 2.64 AI2O3 11.82 11.58 14.56 14.52 14.45 14.91 13.55 Cr203 0.04 0.04 0.04 0.04 0.04 0.10 0.11 FeO* 12.53 12.49 10.94 10.79 10.74 11.41 11.44 MnO 0.42 0.37 0.12 0.13 0.10 0.20 0.10 MgO 14.23 14.30 14.07 13.98 14.04 12.65 13.29 CaO 11.63 11.71 12.58 12.70 12.50 12.15 12.14 Na20 2.40 2.48 2.34 2.29 2.65 2.37 1.91 K20 1.14 1.17 1.27 1.28 1.31 1.28 1.21 Total 98.51 98.56 98.32 97.71 97.53 96.94 97.25 1 Si 6.028 6.050 5.754 5.727 5.715 5.834 6.028 Al™ 1.972 1.950 2.246 2.273 2.285 2.166 1.972 Ti 0.301 0.306 0.328 0.342 0.336 0.302 0.291 AlVI 0.048 0.032 0.258 0.245 0.231 0.444 0.372 Cr 0.005 0.005 0.005 0.005 0.005 0.012 0.013 Fe3+ 0.741 0.672 0.447 0.442 0.375 0.294 0.387 Fe2+ 0.778 0.845 0.888 0.885 0.951 1.124 1.017 Mn 0.052 0.046 0.015 0.016 0.013 0.025 0.012 Mg 3.075 3.095 3.059 3.065 3.089 2.800 2.907 Ca 1.840 1.852 1.988 2.000 1.996 1.947 1.927 (Na)B 0.160 0.148 0.012 0.004 0.053 0.073 (Na)A 0.527 0.562 0.657 0.660 0.761 0.634 0.475 K 0.215 0.220 0.239 0.243 0.249 0.244 0.229 455 Appendix C-4.3 (continued). Mineral chemistry of amphiboles in andesite from Ungaran. Sample 320 320 320 320 320 320 420 Grain PI PI P2 P2 P3 P3 PI Spot R C R C C C C SiC_ 41.38 42.14 41.45 38.43 38.48 38.99 40.91 Ti02 2.17 1.96 2.16 2.18 2.23 2.47 2.03 AI2O3 10.41 9.85 10.10 14.87 14.67 14.06 15.46 CT2O3 0.05 0.04 0.04 0.04 0.04 0.04 0.10 FeO* 15.25 13.73 15.16 11.06 11.24 12.33 10.84 >MnO 0.55 0.52 0.66 0.14 0.14 0.16 0.15 MgO 12.13 13.02 12.02 14.08 13.91 13.24 13.92 CaO 11.76 11.51 11.70 12.28 12.40 12.27 11.95 Na20 1.79 1.91 1.74 2.24 2.26 2.23 2.20 2.00 K20 1.18 0.96 1.15 1.18 1.22 1.12 Total 96.67 95.60 96.14 96.46 96.55 96.89 98.47 Si 6.210 6.327 6.254 5.678 5.702 5.784 5.865 rAl™ 1.790 1.673 1.746 2.322 2.298 2.216 2.135 Ti 0.245 0.221 0.245 0.242 0.249 0.276 0.219 1 A™ 0.052 0.070 0.050 0.268 0.265 0.243 0.478 CT 0.006 0.005 0.005 0.005 0.005 0.005 0.011 Fe3+ 0.647 0.647 0.624 0.731 0.643 0.598 0.680 -Fe2+ 1.267 1.077 1.289 0.636 0.750 0.931 0.619 Mn 0.070 0.066 0.084 0.018 0.018 0.020 0.018 Mg 2.713 2.913 2.703 3.100 3.072 2.927 2.974 Ca 1.921 1.881 1.920 1.979 2.000 1.979 1.866 0.080 0.021 0.000 0.021 0.134 (Na)B 0.079 0.119 0.446 0.437 0.632 0.659 0.630 0.487 (Na)A 0.450 K 0.229 0.187 0.225 0.226 0.234 0.215 0.186 456 Appendix C-4.3 (continued). Mineral of amphiboles in andesite from Ungaran. Sample 420 323 440 440 440 440 440 Grain PI PI PI PI PI P2 P2 Spot R C R C R R C SiC_ 40.68 36.03 42.25 41.97 42.08 40.46 42.11 TO2 2.12 4.46 1.78 2.24 2.21 2.22 1.90 AI2O3 14.82 14.09 9.38 11.19 10.66 10.75 10.57 Cr203 0.10 0.11 0.04 0.04 0.04 0.04 0.04 FeO* 10.91 14.78 14.41 12.75 14.05 15.00 14.45 MnO 0.12 0.26 0.68 0.39 0.55 0.52 0.56 MgO 13.71 13.16 12.87 13.35 12.70 11.37 12.56 CaO 12.04 0.08 11.38 11.71 11.44 11.37 11.38 Na20 2.20 0.66 1.84 2.07 2.06 1.79 1.99 K20 0.99 8.83 1.01 1.14 1.14 1.25 1.03 Total 97.59 92.27 95.58 96.89 96.88 94.73 96.56 Si 5.910 5.306 6.351 6.217 6.253 6.205 6.270 Al™ 2.090 2.446 1.649 1.783 1.747 1.795 1.730 Ti 0.232 0.494 0.201 0.250 0.247 0.256 0.213 A1VI 0.448 0.013 0.171 0.120 0.149 0.125 Cr 0.011 0.013 0.005 0.005 0.005 0.005 0.005 Fe3+ 0.565 0.757 0.529 0.614 0.559 0.702 2+ Fe 0.760 1.820 1.054 1.050 1.133 1.365 1.097 Mn 0.015 0.032 0.087 0.049 0.069 0.068 0.071 Mg 2.968 2.888 2.883 2.947 2.813 2.599 2.787 Ca 1.900 0.014 1.867 1.882 1.849 1.894 1.847 (Na)B 0.100 0.207 0.133 0.118 0.151 0.106 0.153 (Na)A 0.528 0.413 0.484 0.451 0.433 0.431 k 0.186 1.820 0.197 0.218 0.219 0.248 0.199 457 CO wo oo cN I—I wo ON rr r- o co ON r-» © '—I O © i—i rT © oo ©© p .-j co to r-~ i-i wo CN CN O O vq © ro p ON oq cS od © tZ © co* d ON* OO r-H CO PH U I-H © © ©' I-H © CN CO CN CO ON NO ro oo r-ootn-iiorn © . 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"^" ^ "O P "-. p © CN © r-; © ON © ON rt "" —'©©©r-'do' •-H © © d i—' d CN* ON* d OO T rt T-H rt ON ^ . rt rt CN ON CO rt NO OO CS r-- rH r-. -H- rH © © ON I-H r-. © ON ON T CN PH Pi ONI—irroort'-^r-- ©©O©CN©ON [-; CN CN rf wo* ON O ©* O © n' ©' ON i-i © © © I-H © CN* VO CO CO CO CO ON rT © CN ON vo ON CO VO . ON CO ON CN Th CN ON © WO T-H cN © © wo wo PH ON T3 oq OO ON CO vo CN ON© NO ©copp © ON NO* d od © cs © ON ON © © d © <-* © co C-* CN* CO CN CO ON NO CO I—i rT I-H NO CN rT oo CN NO CN CO © NO CO CN r-H ON CN © © NO —* CO © ON U CN I-H wo r-- CN I-H cs IO rT ON © CO © ON r-' © od © co' d ON* ^H' ©* © © t--* CN* ©' CN CO CN CO ON O CO a c •1-H o "o. cd o. o9.9^^9| •rH —J <_> O cd l-H E co CO< PH gal PHPH cd o co 461 Appendix C-6. Mineral chemistry of micas in andesite from Ungaran Sample 930 930 919 323 323 Grain 1 1 1 1 1 1 Spot C R C R C Si02 36.58 38.53 37.34 34.56 35.60 T1O2 4.72 4.43 4.88 4.70 4.77 AI2O3 16.52 16.33 15.13 14.25 14.91 FeO 12.76 13.33 12.81 16.06 16.38 MnO 0.14 0.13 0.34 0.26 0.29 MgO 15.39 16.28 14.60 13.77 14.35 CaO 0.02 0.05 0.02 0.02 0.02 Na20 0.78 0.81 0.62 0.76 0.76 K20 8.40 8.57 9.64 9.33 9.21 Total 95.31 98.46 95.38 93.71 96.29 Mg/Mg+Fe2+ 0.68 0.60 0.67 0.60 0.61 Appendix C-7. Glass compositions from Ungaran. Sample 921 326 326 326 Grain 11 11 Spot C C C C Si02 44.14 38.00 71.95 39.29 Ti02 0.03 2.09 0.73 2.21 A1203 7.47 14.96 17.06 20.91 FeO 4.60 13.00 4.47 12.52 MnO 0.12 0.21 0.06 0.24 MgO 9.33 12.64 .30 12.25 CaO 0.46 12.54 1.79 11.00 Na20 2.50 1.68 2.44 0.30 K20 1.32 4.85 1.15 1.24 462 APPENDIX D TOTAL-ROCK GEOCHEMISTRY Appendix D-l. Oldest Ungaran Appendix D-2. Old Ungaran Appendix D-3. Parasitic Cones Appendix D-4. Young Ungaran 463 Appendix D-l Major and trace element data for samples from Oldest Ungaran. | Sample 921 925 926 929 930 Si02 49.39 51.36 51.38 50.28 60.80 TiC_ 1.08 0.88 0.97 0.98 0.65 A1203 19.25 20.12 18.73 18.39 18.69 FeO* 10.32 9.51 9.55 9.46 6.24 MgO 4.59 3.52 3.94 4.35 1.57 MnO 0.20 0.13 0.20 0.17 0.15 CaO 9.59 8.41 8.87 9.20 5.14 Na20 2.12 2.54 2.56 2.71 2.93 K20 2.02 2.43 2.62 2.74 3.08 P2O5 0.34 0.34 0.35 0.39 0.27 LOI 1.10 0.76 0.83 1.33 0.48 Total 99.49 100.35 99.55 99.41 100.22 Fe203/FeO 1.15 1.14 0.96 1.09 2.03 K20/Na20 0.95 0.96 1.02 1.01 1.05 Mg-number 0.49 0.45 0.48 0.50 0.36 D.I 29.90 35.90 37.20 39.10 58.70 Rb 51 55 78 73 103 Sr 464 424 512 523 408 Zr 115 105 149 154 165 Nb 12 10 12 12 15 Pb 14 14 25 14 23 Th 6 7 8 11 15 Y 25 24 31 31 39 Cr 13 - - . 9 V 286 - - - 124 Sc 22 - - - 10 Co 35 - - - 39 La 24 - _ - 39.20 Ce 48.80 - - - 56 Sm 4.84 - - - 4.83 Eu 1.48 - - - 1.36 Yb 2.19 - - - 2.69 Lu 0.32 - - - 0.42 Hf 2.6 - - - 3.90 Ba 420 - - - 590 Zn 101 - - - 77 Ta 0.41 - - - 0.70 87Sr/86Sr 0.70508 - - 0.70497 464 Appendix D-2. Major and trace element data for samples from Old Ungaran. Sample 918 822 927 928 826 832 Si02 51.92 51.53 51.69 52.91 50.12 49.73 Ti02 0.97 1.02 0.81 0.80 0.98 1.06 A1203 9.88 18.98 18.80 19.17 19.27 20.80 FeO* 9.44 9.34 8.61 8.19 9.61 9.47 MgO 2.98 4.00 4.15 3.45 4.07 3.30 MnO 0.19 0.18 0.18 0.18 0.20 0.18 CaO 7.63 8.74 8.82 8.40 9.11 9.08 Na20 3.15 2.65 3.35 3.50 2.97 2.98 K2Q 2.79 2.31 2.58 2.64 2.22 2.06 P2O5 0.39 0.29 0.29 0.31 0.40 0.35 LOI 0.66 0.96 0.72 0.45 1.05 0.99 Total 99.72 99.54 99.85 100.21 99.56 99.51 Fe203/FeO 2.87 1.31 0.97 1.68 1.58 1.17 K20/Na20 0.89 0.87 0.77 0.75 0.75 0.69 Mg-number 0.41 0.50 0.53 0.49 0.49 0.44 D.I 43.10 36.10 43.60 46.20 47.00 42.20 Rb 81 64 73 69 56 40 Sr 445 448 563 551 678 415 Zr 155 133 139 130 154 105 1 Nb 14 10 11 11 12 8 Pb 19 18 13 15 17 31 Th 14 7 13 8 14 2 . Y 32 31 26 35 35 25 Cr 7 - - - 16 11 V 262 - - - 225 256 Sc 18 - - - 19 20 Co 29 - - - 33 40 La 40.90 - - - 48.60 17.90 Ce 72.80 - - - 85.40 37.80 Sm 6.44 - - - 7.40 4.63 Eu 1.86 - - - 2.28 1.48 Yb 2.68 - - - 2.85 2.45 Lu 0.46 - - - 0.44 0.37 Hf 3.20 - - - 2.90 2.80 Ba 598 - - - 530 534 Zn 185 - - - 148 105 Ta - - - _ 0.53 0.24 8?Sr/86Sr - - - - 0.70519 465 Appendix D-2 (continued). Major and trace element data for samples from Old Ungaran. Sample 823 820 922 923 924 Si02 51.47 53.95 53.18 53.65 58.43 Ti02 0.87 0.72 0.80 0.79 0.67 AI2O3 19.22 19.30 18.90 19.21 20.16 FeO* 9.08 7.73 8.85 8.37 7.24 MgO 4.10 2.88 3.52 3.17 1.92 MnO 0.17 0.18 0.20 0.15 0.15 CaO 8.73 8.51 8.48 8.56 5.15 Na20 3.32 2.87 2.39 2.72 2.27 K20 1.64 2.65 2.44 2.58 3.11 P2O5 0.35 0.35 0.27 0.31 0.31 LOI 1.05 0.86 0.97 0.49 0.59 Total 99.52 99.58 99.71 99.72 99.78 Fe_O_JFc0 1.32 1.29 1.18 2.57 1.17 K20/Na20 0.49 0.92 1.02 0.95 1.37 Mg-number 0.50 0.45 0.47 0.46 0.37 D.I 37.80 42.60 38.10 40.80 53.60 Rb 65 71 58 66 94 Sr 551 645 458 494 421 Zr 135 158 124 127 181 Nb 14 16 10.50 9 14 Pb 10 13 15 16 14 Th 7 8 7 9 13 Y 25 26 28 27 42 Cr 10 36 9 - 4 V 240 188 215 - 143 Sc 23 17 16 . 11 Co 32 25 29 . 26 La 34.40 41.10 23.20 - 40.50 Ce 63.10 78.80 44 - 74.50 Sm 6.43 6.17 4.49 - 6.50 Eu 1.84 1.76 1.37 - 1.77 ! Yb 2.46 1.47 2.13 - 3.83 Lu 0.40 0.36 0.35 - 0.60 Hf 3.10 3.60 2.40 - 4.40 Ba 533 590 460 - 629 Zn 135 102 131 - 100 Ta 0.78 0.54 0.34 - 0.60 87Sr/86Sr - 0.70467 - - 0.70477 466 Appendix D-3. Major and trace element data for samples from Parasitic Cones. Sample 429 202 426 428 427 425 Si0 57.32 54.47 53.93 54.25 56.16 52.85 2 0.78 0.69 0.90 Ti0 0.60 0.67 0.79 2 17.69 19.50 18.21 18.63 20.00 18.56 AI2O3 6.36 7.86 8.71 8.23 7.01 7.96 FeOMgO* 2.86 2.67 2.60 3.02 2.79 4.04 MnO 0.18 0.19 0.25 0.18 0.17 0.15 CaO 6.57 7.48 7.56 8.15 7.35 8.12 Na20 3.32 3.28 3.55 3.06 3.06 3.12 3.25 2.47 2.30 2.26 2.50 m 2.95 K2-• *__^-O* P2O5 0.22 0.28 0.43 0.52 0.27 0.26 LOI 1.93 0.35 1.50 0.88 0.24 1.54 1 Total 99.58 100.11 99.49 100.18 99.77 99.43 Fe203/FeO 3.04 3.75 3.85 0.99 1.02 1.47 K20/Na20 0.89 0.99 0.70 0.75 0.74 0.80 Mg-number 0.50 0.43 0.39 0.44 0.46 0.52 D.I 52.10 47.30 46.10 43.20 45.80 41.20 Rb 97 54 67 44 87 73 Sr 436 622 586 643 509 462 ; Zr 161 104 114 112 175 142 Nb 13 6 8 8 18 10 Pb 25 23 13 16 17 20 Th 16 2 8 5 11 14 Y 23 27 35 24 26 23 Cr 8 - - 7 - 17 V 125 - - 235 - 219 Sc 11 _ - 23 - 18 Co 21 - - 26 - 32 La 30.80 - - 29.20 - 30.10 Ce 54.70 _ - 55.30 - 58.40 Sm 4.26 - - 4.80 - 5 Eu 1.15 - - 1.58 - 1.48 Yb 2.24 - - 2.26 - 2.21 Lu 0.31 - - 0.39 - 0.31 Hf 3.90 _ - 3 - 3.60 Ba 489 - - 570 - 430 Zn 109 - - 182 - 100 Ta 0.77 - - 0.29 - - 87Sr/86Sr 0.70497 - - - 0.70527 467 Appendix D-3 (continued). Major and trace element data for samples from Parasitic Cones. Sample 4241 424 423 919 917 SiC_ 53.33 56.51 56.11 56.68 49.04 Ti02 0.91 0.70 0.73 0.65 1.06 A1203 18.62 18.32 18.14 18.37 18.52 FeO* 8.19 7.14 7.01 6.99 10.06 MgO 3.79 2.93 2.85 2.43 4.76 MnO 0.15 0.17 0.15 0.17 0.18 CaO 8.18 6.98 7.11 6.85 9.99 Na20 3.18 3.59 3.43 3.25 3.12 K20 2.56 2.91 3.09 2.62 2.27 P2O5 0.25 0.25 0.27 0.28 0.29 LOI 0.84 0.98 0.63 1.71 0.71 Total 99.52 99.96 99.88 99.65 99.73 Fe203/FeO 0.83 1.01 1.58 3.01 1.63 K20/Na20 0.81 0.81 0.90 0.81 0.73 Mg-number 0.50 0.48 0.47 0.43 0.51 D.I 42.00 51.00 50.50 50.00 34.40 Rb 74 72 92 75 62 Sr 460 439.50 417 421 468 Zr 142 135 152 156.50 132 Nb 12 10 11 9 11 Pb 16 12 17 17 21 Th 11 7 16 15 14 Y 22 24 27 28 52 Cr - - - 6 8 V _ . - 155 231 Sc _ - - 18 10 Co _ . - 22 19 La _ _ - 18.70 28.90 Ce _. _ - 53.80 41.90 Sm _ - - 3.58 5.47 Eu _ - - 1.33 1.60 Yb . _ - 2.41 2.72 Lu _ . 0.40 0.44 Hf _ - 3.60 2.40 Ba _ - 550 377 Zn .. - 132 86 Ta . _ - 0.45 0.39 - - 0.70505 87Sr/86Sr - 468 Appendix D-4. Major and trace element data for samples from Young Ungaran. Sample 821 824 825 830 827 828 _ Si02 55.82 50.91 54.96 53.84 55.20 53.82 Ti02 0.76 0.95 0.87 0.89 0.67 0.84 — — *—* _, 20.36 18.54 19.50 18.53 19.66 18.22 _• ~> AI2OFeO*3 7.33 9.20 7.92 8.65 6.79 8.03 MgO 3.40 4.50 2.53 3.14 2.61 3.33 0 0.19 0.18 0.15 0.15 0.20 0.18 MnCaOO 5.19 8.96 7.55 8.07 7.37 7.84 Na20 2.72 3.07 2.82 2.76 3.30 3.65 K2O 2.73 2.57 2.75 2.84 2.30 2.81 P2O5 0.28 0.28 0.33 0.36 0.27 0.28 LOI 1.22 0.84 0.62 0.77 1.63 1.00 Total 100.03 99.46 100.82 99.61 100.02 99.97 Fe203/FeO 5.37 1.78 0.96 1.79 1.51 5.11 K20/Na20 1.00 0.84 0.98 1.03 0.70 0.77 Mg-number 0.50 0.51 0.41 0.44 0.46 0.48 D.I 49.00 41.20 45.10 42.70 46.30 47.50 Rb 46 66 58 80 72 81 Sr 366 455 547 440 602 541 Zr 198 142 160 152 179 154 Nb 14 10. 13 11 14 12 Pb 27 21 18 19 23 17 Th 26 8 11 11 14 12 Y 34. 28 29 27 27 28 Cr 4 24 4 - - - V 118 264 192 - - - Sc 12 36 18 - - Co 16 37 24 - - - La 51.30 33.80 35 - - - Ce 74.70 65 16.2 - - - Sm 6.09 5.97 5.80 - - - Eu 1.69 1.87 1.59 - - - Yb 2.96 2.55 2.48 - - - Lu 0.50 0.45 0.36 - - - Hf 4.50 3.60 3.90 - - - Ba 767 530 537 - - - Zn 151 - 97 - - - Ta 0.77 0.34 0.61 - - - 87Sr/86Sr - - 0.70474 - - 469 Appendix D-4 (continued). Major and trace element data for samples from Young Ungaran. Sample 829 415 833 326 320A 438 SiO_ 55.60 54.36 50.88 48.95 49.06 51.04 Ti02 0.81 0.72 1.03 0.99 0.93 0.97 ^Al203 18.93 18.73 20.08 18.34 18.45 19.12 FeO* 7.94 8.24 9.21 9.73 9.87 9.40 MgO 2.65 2.69 4.07 5.03 5.56 4.44 MnO 0.15 0.20 0.19 0.18 0.20 0.18 CaO 7.33 7.92 9.03 9.49 9.37 9.19 Na20 2.89 3.36 2.51 3.60 3.30 2.60 K20 2.85 2.62 1.40 1.87 1.87 1.83 P2O5 0.26 0.37 0.29 0.60 0.49 0.39 LOI 0.59 0.79 1.31 1.22 0.90 0.84 Total 99.85 99.87 99.87 99.60 99.57 99.73 Fe203/FeO 1.21 1.46 6.74 1.11 1.80 1.71 K20/Na20 0.99 0.78 0.56 0.52 0.57 0.70 Mg-number 0.43 0.41 0.50 0.53 0.55 0.51 D.I 46.50 45.70 31.20 38.70 37.30 32.80 Rb 82 67 13 40 51 44 Sr 512 488 380 597 574 489 Zr 147 159 154 163 165 135 Nb 9 14 11 12 14 11 Pb 15 23 33 16 17 18 Th 9 15 10 8 11 5 Y 26 28 26 28 29 26 Cr - - 18 62 - 8 V . - 212 193 - 234 Sc _ - 24 27 - 22 Co _ _ 29 36 - 31 La _, . 30.80 51 - 26.90 Ce _. _ 52.50 97.80 - 50.30 Sm _. _ 4.80 9.40 - 4.43 Eu _ _ 1.34 2.61 - 1.46 Yb _, _ 2.26 2.59 - 2.03 Lu _ - 0.39 0.47 - 0.35 Hf __ _ 3.30 3.35 - 3.02 Ba _, _ 581 5.30 - 412 Zn _ _ 107 117 - 113 Ta - - 0.37 - - 0.52 87Sr/86Sr - 0.7051C> 0.70498 470 Appendix D-4 (continued). Major and trace element data for samples from Young Ungaran. Sample 320 323 419 420 440 417 Si02 56.67 58.86 55.98 58.31 58.59 51.98 Ti02 0.64 0.57 0.75 0.56 0.65 1.00 AI2O3 18.42 18.84 18.93 18.29 19.28 18.26 FeO* 7.00 5.96 8.00 6.16 6.71 8.92 MgO 3.01 1.98 2.48 2.25 2.15 3.43 MnO 0.17 0.17 0.18 0.18 0.19 0.13 CaO 7.12 5.63 6.22 6.29 5.39 8.86 Na20 3.30 3.90 3.00 3.08 2.85 3.20 K20 2.74 3.04 3.15 3.03 2.88 2.76 P2O5 0.33 0.22 0.31 0.30 0.27 0.26 LOI 0.70 0.89 1.00 1.45 0.84 1.20 Total 99.68 99.75 99.97 99.98 99.94 99.55 Fe203/FeO 1.53 1.78 1.92 1.88 1.32 2.26 K20/Na20 0.83 0.78 1.05 0.98 1.01 0.86 Mg-number 0.49 0.42 0.41 0.45 0.41 0.46 D.I 49.30 41.30 49.60 53.50 54.10 43.40 Rb 84.50 79 91 104 93 62 Sr 494 411 450 498 399 499 Zr 172 168 166 182 179 139 Nb 14 13 14 16 11 9 Pb 20 23 20 20 21 19 Th 18 18 18 20 16 13 Y 28 24 29 31 27 24 | Cr - - 9 8 6 12 V - - 168 116 96 290 Sc - - 14 9 10 30 Co - - 23 18 18 39 La - - 39.90 41.80 32.70 28.60 Ce - - 71.80 70.80 59.40 53.20 S0 m - - 5.27 5.63 4.70 4.90 Eu - - 1.49 1.42 1.32 1.53 "\ 7~\ Yb - - 2.32 2.48 2.21 2.14 Lu - - 0.38 0.41 0.41 0.35 HT T_f* - - 3.72 4.20 3.54 4 BT-Nia - - 520 570 650 590 Zr_?n - - 120 148 122 Ta 0.45 0.81 0.87 0.68 87Sr/86Sr - - 0.70487 471 Appendix D-4 (continued). Major and trace element data for samples from Young Ungaran. Sample 418 416 422 328 432 435 S1O2 50.00 55.02 56.65 56.88 54.44 54.22 ; Ti02 0.96 0.73 0.65 0.69 0.74 0.84 AI2O3 18.42 18.64 19.61 18.42 18.42 19.62 FeO* 9.39 7.62 7.20 6.61 7.38 7.50 MgO 3.83 2.52 2.15 2.92 3.55 3.16 MnO 0.18 0.18 0.17 0.15 0.18 0.16 ' ^ • - CaO 9.19 7.36 6.03 7.00 8.11 8.10 • Na20 3.93 3.31 3.04 3.36 3.55 3.19 • K20 2.83 2.43 2.84 2.80 2.88 2.59 P2O5 0.46 0.22 0.40 0.33 0.39 0.23 LOI 0.81 1.97 1.26 0.44 0.36 0.39 • m Total 99.50 99.65 99.52 100.41 99.96 99.97 Fe203/FeO 2.94 1.91 0.83 0.93 1.33 1.51 K20/Na20 0.72 0.73 0.93 0.83 0.81 0.81 Mg-number 0.47 0.42 0.40 0.49 0.51 0.48 D.I 44.30 46.70 51.30 50.50 47.10 43.80 Rb 50 59 89 84 86 58 i Sr 625 408 468 491 554 475 Zr 162 148 175 176 175 151 Nb 13 12 17 13 15 14 Pb 18 16 20 25 17 20 Th 15 6 11 17 17 13 Y 29 27 27 26 25 28 Cr 11 - 21 - - - V 289 - 80 - - - Sc 25 - 8 - - - Co 32 - 10 - - - La 21 - 44.60 - - - Ce 113 - 77.10 - - - Sm 6.27 - 5.63 - - - Eu 2.19 - 1.42 - - - Yb 2 - 2 - - - Lu 0.34 - 0.41 - - - Hf 3.75 - 3.40 - - Ba 413 - 684 - - - Zn 99 - 142 - - - Ta 0.74 - 0.87 - - - 87Sr/86Sr - - " 472 Appendix D-4 (continued). Major and trace element data for samples from Young Ungaran. Sample 325 834 433 439 438A 437 Si02 53.03 56.66 57.21 54.42 56.10 56.00 Ti02 0.70 0.68 0.71 0.72 0.73 0.78 AI2O3 19.77 19.02 18.66 19.52 18.66 18.51 FeO* 7.94 6.71 7.16 7.83 7.39 7.61 MgO 3.33 2.34 2.59 2.87 3.16 3.24 MnO 0.17 0.15 0.16 0.17 0.16 0.18 CaO 8.46 6.88 7.13 7.33 7.06 7.49 Na20 3.34 3.04 3.23 3.26 2.81 2.76 K20 2.53 2.64 2.69 2.74 2.54 2.62 P205 0.37 0.31 0.28 0.40 0.30 0.28 LOI 0.29 1.57 0.18 0.74 1.09 0.53 Total 99.52 99.66 100.26 99.77 99.96 99.95 Fe203/FeO 2.99 1.46 4.88 2.70 1.50 2.43 K20/Na20 0.76 0.87 0.83 0.84 0.90 0.95 Mg-number 0.48 0.43 0.44 0.45 0.49 0.49 D.I 43.20 49.20 49.90 45.90 45.90 45.20 Rb 47 76 80 61 77 76 Sr 475 552 430 580 453 450 Zr 132 174 149 190 161 141 Nb 10 14 9 11 12 10 Pb 17 18 18 19 17 20 Th 11 15 12 14 14 5 Y 28 27 24 27 24 26 Cr - 11 4 - 10 11 V - 149 155 _ 167 195 Sc - 14 12.50 - 16 18 Co - 20 28 - 28 31 La - 39.20 28.90 - 37.50 31.50 Ce - 71 52.90 - 62.80 61.80 Sm - 5.38 4.73 - 4.85 5.22 Eu - 1.53 1.37 - 1.45 1.51 Yb - 2.87 2.51 - 2.66 2.65 Lu - 0.44 0.37 _ 0.40 0.40 Hf - 4.81 4.13 - 4.34 3.63 Ba - 600 553 _ 570 390 Zn - 71 96 . 114 8 Ta 0.66 0.76 0.83 0.43 87Sr/86Sr - - 473 APPENDIX E CIPW NORMATIVE MINERALOGY Appendix E-l. Oldest Ungaran Appendix E-2. Old Ungaran Appendix E-3. Parasitic Cones Appendix E-4. Young Ungaran Appendix E-l. CIPW normative mineralogy (in wt.%) from Oldest Ungaran. Sample 921 925 926 929 930 Q - 0.05 - - 15.69 Or 11.94 14.36 15.49 16.19 18.20 Ab 17.94 21.49 21.66 22.93 24.79 An 37.05 36.33 31.88 29.93 23.74 Ne - - - - - Dy 6.91 2.66 8.20 10.94 - Hy 16.05 19.76 14.46 3.07 11.99 a 3.85 - 2.68 10.69 - Ml 2.49 2.30 2.31 2.29 1.51 D 2.05 1.67 1.84 1.86 1.23 Ap 0.81 0.81 0.83 0.92 1.51 C - - - - 1.84 Appendix E-2. CIPW normative mineralogy (in wt.%) from Old Ungaran. Sample 918 822 927 928 826 832 Q ------Or 16.49 13.65 15.25 15.60 13.12 12.18 Ab 26.65 22.42 28.34 29.61 25.13 25.21 An 31.87 33.08 28.65 28.81 32.70 37.30 Ne ------ Dy 2.89 6.99 10.97 9.04 8.24 4.58 Hy 11.94 17.55 0.07 5.74 4.45 5.54 a 4.63 0.65 11.86 6.67 10.37 9.24 M 2.28 2.26 2.08 1.98 2.32 2.29 11 1.84 1.94 1.54 1.52 1.86 2.01 Ap 0.92 0.69 0.69 0.73 0.95 0.83 C . . _ 475 Appendix E-2 (continued). CIPW normative mineralogy (in wt.%) from Old Ungaran. Sample 823 820 922 923 924 Q - 2.67 3.42 2.50 15.98 Or 9.69 15.66 14.42 15.25 18.38 Ab 28.09 24.28 20.22 23.03 19.21 An 32.70 31.96 33.64 32.59 23.53 Ne - - - - - Dy 6.92 6.68 5.57 6.57 - Hy 12.71 13.97 17.62 15.49 14.26 a 4.33 - - - - Mt 2.19 1.87 2.14 2.02 1.75 n 1.65 1.37 1.52 1.50 1.27 Ap 0.83 0.83 0.64 0.73 0.73 c - - - - 4.44 Appendix E-3. CIPW normative mineralogy (in wt.%) from Parasitic Cones. Sample 429 202 426 428 427 425 Q 6.58 0.36 1.48 3.70 6.51 - Or 17.44 19.21 14.60 13.59 13.36 14.78 Ab 28.09 27.75 30.04 25.89 25.89 26.40 An 24.66 28.89 26.46 30.31 34.17 29.26 Ne ------ Dy 5.41 5.37 6.95 5.63 0.45 7.72 Hy 12.82 14.38 14.52 15.45 15.88 15.78 a - - - - - 0.43 Mt 1.54 1.90 2.10 1.99 1.69 1.92 n 1.14 1.27 1.50 1.48 1.31 1.71 Ap 0.52 0.66 1.02 1.23 0.64 0.62 c ------476 Appendix E-3 (continued). CIPW normative mineralogy (in wt.%) from Parasitic Cones. Sample 424A 424 423 919 917 Q 3.37 - 3.24 6.99 - Or 17.20 15.13 18.26 15.49 13.41 Ab 30.37 26.91 29.02 27.50 20.99 An 25.28 28.98 24.98 27.80 29.83 Ne - - - - 2.93 Dy 6.43 8.28 7.12 3.65 14.71 Hy 13.22 15.61 12.77 13.41 - 01 - - 0.10 - 11.34 Mt 1.69 1.98 1.73 1.69 2.73 11 1.33 1.73 1.39 1.23 2.01 Ap 0.59 0.59 0.64 0.66 0.67 C - - - - - Appendix E-4. CIPW normative mineralogy (in wt.%) from Young Ungaran. | Sample 821 824 825 827 830 828 Q 9.81 - 5.02 4.81 2.60 - Or 16.14 15.19 16.25 13.59 16.79 16.61 Ab 23.01 25.97 23.86 27.92 23.35 30.88 An 23.92 29.22 32.43 32.04 29.79 25.04 Ne ------ Dy - 11.11 2.41 2.31 6.61 10.03 Hy 18.00 0.75 15.20 14.27 15.62 8.77 Ol - 12.39 - - - 3.62 Mt 1.77 2.22 1.91 1.64 2.09 1.94 n 1.44 1.80 16.50 1.27 1.69 1.60 Ap 0.66 0.66 0.78 0.64 0.85 0.66 c 4.17 - - _ - - 477 Appendix E-4 (continued). CIPW normative mineralogy (in wt%) from Young Ungaran. Sample 829 415 833 326 320A 438 Q 5.24 1.73 1.72 - - . Or 16.84 15.49 8.27 11.05 11.05 10.82 Ab 24.45 28.43 21.24 24.35 24.35 22.00 An 30.27 28.29 39.39 28.37 30.01 35.10 Ne - - - 3.31 1.93 - Dy 3.70 7.22 2.92 12.24 10.96 6.59 Hy 14.98 13.97 20.44 - - 19.51 a - - - 14.00 15.67 0.28 Mt 1.92 1.99 2.23 2.35 2.39 2.27 n 1.54 1.37 1.96 1.88 1.77 1.84 Ap 0.62 0.88 0.69 1.42 1.16 0.92 C ------ Sample 320 323 419 420 440 417 Q 5.23 6.94 5.55 9.54 12.97 - Or 16.19 17.97 18.62 17.91 17.02 16.31 Ab 27.92 33.00 25.38 26.06 24.11 27.07 An 27.36 24.93 28.83 27.14 24.98 27.31 Ne ------ Dy 4.84 1.32 - 1.77 - 12.48 Hy 14.30 12.04 16.66 12.89 14.18 4.01 Ol - - - - - 7.10 Mt 1.69 1.43 1.93 1.49 1.62 2.16 Hm - - - - - 0.74 n 1.22 1.08 1.42 1.06 1.23 1.92 Ap 0.78 0.52 0.73 0.71 0.64 0.60 C - - 0.02 - 2.32 478 Appendix E-4 (continued). CIPW normative mineralogy (in wt.%) from Young Ungaran. Sample 418 416 422 328 432 435 Q - 4.36 8.78 5.53 - 1.50 a 16.73 14.36 16.79 16.55 17.02 15.31 Ab 20.76 28.01 25.72 28.43 30.04 26.99 An 24.27 28.83 27.30 26.91 25.83 31.57 Ne 6.76 - - - - - Dy 15.28 5.25 - 4.71 9.84 5.92 Hy - 13.61 14.84 13.47 11.19 14.50 a 10.38 - - - 1.75 - Mt 2.27 1.84 1.74 1.60 1.78 1.81 n 1.82 1.39 1.23 1.31 1.41 1.60 Ap 1.09 0.52 0.95 0.78 0.90 0.54 C - - 1.53 - - - Sample 325 834 433 439 438A 437 Q - 7.91 6.63 2.13 7.15 6.40 Or 14.95 15.60 15.90 16.19 15.01 15.49 Ab 28.26 25.72 27.33 27.58 23.78 23.35 An 31.49 30.42 28.48 30.54 30.81 30.38 Ne ------ Dy 6.73 1.38 4.25 2.69 1.88 4.12 Hy 10.95 13.84 13.63 16.07 16.54 15.89 a 3.29 - - - - - Mt 1.92 1.62 1.73 1.89 1.79 1.84 n 1.33 1.29 1.35 1.37 1.39 1.48 Ap 0.88 0.73 0.66 0.95 0.71 0.66 c ------479 APPENDIX F Program to calculate primary magma compositions by adding olivine of composition Fo90, and using KD = 0.3. The program was written by R. Sukhjar and the author. 480 Appendix F. Program to calculate primary magma compositions by adding olivine Fo90, and using KD = 0.3. Examples of results are also listed. 4 C1 = 0 5 INPUT "sample no. ";N$ 6 INPUT "enter filename";F$ 7 LPRINT" Filename:";F$ 8 OPEN" I'M, F$ 9 INPUT#1,S;T.A,FE.F,MN,MG.C.N,K,P 20 LET MPMG=MG/40.32 30 LET MPF=F/71.85 40 LET I=.3*MPF/MPMG 50 LET FEO=(I/(l+I))*71.85 60 LET MGO-(1/(1+I))*40.32 61 LET SIO=.5*60.05 62 LET TOT= FEO+MGO+SI0 63 LET FEOOL=FEO*100/TOT 64 LET MGOL=MGO*100/TOT 65 LET SIOOL=SIO*100/TOT 70 LET MIXMG=.005*MGOL+MG 80 LET MIXF=.005*FEOOL+F 81 LET MIXSI=.005*SIOOL+S 82 LET MTXT=T 83 LET MIXAL=A 84 LET MIXFEO=FE 85 LET MIXMN=MN 86 LET MIXCA=C 87 LET MIXNA=N 88 LET MTXK=K 89 LET MIXP=P 91 LET T=MIXP+MIXK+MIXNA+MIXCA+MIXMN+MIXFEO+MIXAL+MIXS I+MIXMG+MIXF+MIXT 92 LET SIO2=MIXSI*100/T 93 LET TIO2=MTXT*100/T 94 LET 4\L2O3=MIXAL*100/T 95 LET FE2O3=MIXFEO*100/T 96 LET FEON=MIXF*100/T 97 LET MNO=MIXMN*100/T 98 LET MGON=MIXMG*100/T 99 LET CAO=MIXCA*100/T 100 LET NA2O=MTXNA*100/T 101 LET K2O=MIXK*100/T 102 LET P2O5=MIXP*100/T 110 LET S=SI02 115 LET T=TI02 120 LET A=AL203 125 LET FE=FE203 130 LET F=FE0N 135 LET MN=MN0 140 LET MG=MG0N 145 LET C=CA0 150 LET N=NA20 155 LET K=K20 160 LET P=P205 28262422200 C1=C1+LET MPF=FEMPMG=MGMGN=MGON/40.3FEN=FE0N/71.81 NN 52 481 Appendix F. Program to calculate primary magma compositions by adding olivine Fo90 and using KQ = 0.3. Examples of results are also listed. 281 IF MGN/FEN=>2.699 6 THEN 285 282 GOTO 40 285 LET MD=13/K20 286 LET Cl=Cl/2 289 LPRINT "Program to calculate primary magma compositions 290 by adding olivine (Fo90), and using KD = 0.3." 291 PRINT " C1,SI02,TI02,AL203,FE203 " A1203 Fe203" 292 LPRINT " Fo90 added Si02, Ti02 293 LPRINT C1,SI02,TI02.AL203,FE203 " 294 PRINT C1,SI02,TI02,AL203,FE203 " Na20' 295 PRINT " FEON,MNO,MGON,CAO,NA20" CaO 296 LPRINT " FeO MnO MgO 297 LPRINT FEON,MNO,MGON,CAO,NA20 298 PRINT FEON,MNO.MGON,CAO,NA20 PRINT " K20,P205,MDK20 " Melting degree" 299 K20,P205,MD 300 LPRINT " K20 P205 LPRINPRINT T K20.P205 MD 301 STOP 400 END 420 Example 1 Sample number:s.832 Program to calculate primary magma compositions by adding olivine (Fo90) and using KD 0.3 Fo90 added Si02, Ti02 A1203 Fe203 31.5 47.44072 .7819645 15.34421 1.394258 FeO MnO MgO CaO Na20 9.618446 .1327864 14.61307 6.698337 2.198353 K20 P205 Melting degree 1.519667 .258196 8.554504 Example 2 Sample number:s.326 Program to calculate primary magma compositions by adding olivine (Fo90), and using KD = 0.3. Fo90 added Si02, Ti02 A1203 Fe203 23.5 47.59324 .7927468 14.68584 1.561471 FeO MnO MgO CaO Na20 9.032582 .1441359 13.73025 7.599164 2.882715 K20 P205._ Melting degree 1.497412 .4804529 8.681648 482 APPENDIX G Program to calculate primary magma compositions by adding olivine of composition J':, Fo90 and clinopyroxene, and using KD = 0.3. The program was written by R. Sukhjar ; and the author. 483 Appendix G. Program to calculate primary magma compositions by adding olivine Fo^ and clinopyroxene (Mg-number = 0.83), and using KD = 0.3. The composition of clinopyroxene is taken from Appendix C-2.2.1, sample 922, grain P2. Examples of results are also listed. 4 ci=o 5 INPUT "sample no. ";N$ 6 INPUT "enter filename";F$ 7 LPRINT" Sample number:";F$ 8 OPEN,,I*\l,F$ 9 INPUT#1,S,T,A,FE,F,MN.MG,C,N,K,P 20 LET MPMG=MG/40.32 30 LET MPF=F/71.85 40 LET I=.3*MPF/MPMG 50 LET FEO=(I/(l+D) -71.85 60 LET MGO=(1/(1+D)*40.32 61 LET SIO=.5*60.05 62 LET TOT= FEO+MGO+SIO 63 LET FEOOL=FEO*100/TOT 64 LET MGOL=MGO*100/TOT 65 LET SIOOL=SIO*100/TOT 70 LET MIXMG=.005* (.3*MGOL+.7*14.44)+MG 80 LET MIXF=.005*(.3*FOOL+.7*5.21)+F 81 LET MIXSI=.005* (.3*SIOOL+.7*48.86)+S 82 LET MIXT=T+.005*.7*.71 83 LET MIXAL=A+.005*.7*5.16 84 LET MIXFEO=FE+.005*(1.3*.7) 85 LET MIXMN=MN+.005*.7*.16 86 LET MIXCA=C+.005*.7*23.65 B7 LET MIXNA=N+.005*.7*.3 88 LET MIXK=K qq LKT MIXP=P 91 LET T=MIXP+MIXK+MIXNA+MIXCA+MIXMN+MIXFEO+MIXAL+MIXSI+MIXMG+MIXF+MIXT 92 LET SIO2=MIXSI*100/T 93 LET TIO2=MIXT*100/T 94 LET AL2O3=MIXAL*100/T 95 LET FE2O3=MIXFEO*100/T 96 LET FEON=MIXF*100/T 97 LET MNO=MIXMN*100/T 98 LET MGON=MIXMG*100/T 99 LET CAO=MIXCA*100/T 100 LET NA2O=MIXNA*100/T 101 LET K2O=MIXK*100/T 102 LET P2O5=MIXP*100/T 110 LET S=SI02 115 LET T=TI02 120 LET A=AL203 125 LET FE=FE203 130 LET F=FEON 135 LET MN=MNO 140 LET MG=MGON 145 LET C=CAO 150 LET N=NA20 155 LET K=K20 160 LET P=P205 200 LET MGN=MGON/40.32 220 LET FEN=FEON/71.85 240 LET MPMG=MGN 26280 LEC1=C1+T MPF=FE1 N 484 Appendix G (continued). Program to calculate primary magma compositions by adding olivine Fo90 and clinopyroxene (Mg-number = 0.83), and using Kj} = 0.3. The composition of clinopyroxene is taken from Appendix C-2.2.1, sample 922, grain P2. Examples of results are also listed. 281 IF MGN/FEN=>2.6996 THEN 285 282 GOTO 40 285 LET MD=13/K20 286 LET Cl=Cl/2 289 LPRINT "Program to calculate primary magma compositions by adding olivine (Fo90) + clinopyroxene using KD = 0.3" 290 LPRINPRINT T " "C1,SI02,TI02,AL203,FE20 Fo90+cpx added Si02, 3 " A1203 Fe203' 291 Ti02 292 LPRINT Cl,SIO2,TIO2,AL2O3,FE203 293 PRINT C1,SI02,TI02,AL203,FE203 " 294 PRINT " FEON,MNO,MGON,CAO,NA20" MgO CaO Na20' 295 LPRINT "• FeO MnO 296 LPRINT FEON,MNO,MGON,CAO,NA20 297 PRINT FEON,MNO,MGON,CAO, NA20 298 PRINT " K20,P205,MD" Melting degree" 299 LPRINT " K20 P205 300 LPRINT K20,P205,MD 301 PRINT K20,P205.MD 400 STOP 420 END Example 1 Sample number:s.832 Program to calculate primary magma compositions by adding olivine (Fo90) + clinopyroxene using KD =.0.3 Fo90+cpx added Si02, Ti02 A1203 Fe203 38 49.681 .9041825 15.79098 1.61975 FeO MnO MgO CaO Na20 6.488283 .1623133 9.838627 11.65363 2.164634 K20 P205 Melting degree 1.450221 .2463967 8.964149 Example 2 Sample number:s.326 ^"llSSSSSSnTSS --VrPOSiCi°nS »y adding olivine Fo90+cPx added Si02. Ti02 um pe 2 4 8747 "• iS - S "•«"" *•» CaO Na20 6.803543 .1650014 10.36025 11.62687 2.741994 l 3Q?^« Z205 Melting degree 1.394328 .447378 9.323491 485 cn cn >n >o o ON *_ o o o o T-H o c d d d d d d /-> D- •<* C/_ 00 ON T-H 4— X—• ty VO NO o o o o >N O o q q q o rg o3 d d T-H T-H od ON PH a TJ c a • 1—« j=> o o o o o o KH 'o cs CS oo oo oo oo D- rt B d d d d d d /—\ < O OO T-H oX —N q q q o O q 4-J .—i cd d d d d d d X> o «+H O a> o 3 6 •iS 3 00 1 00 486 APPENDIX I PETMIX CALCULATIONS A computer program of PETMIX calculations written by K.W. Laurent (U.S. Geological Survey) was used to evaluate the possibility of various models linking particular rock types by fractional crystallisation. The program has been used to test the proposition that rocks A and B are related to each other by addition or substraction of fractionating phases and can be formulated as: A = b% B + x% X + y% Y + z% Z. The proportions of fractionating phases are determined by a least squares techniques to obtain a differentiate by minimizing the sum of the squares of differences between the observed composition A and that calculated by mixing B, X, Y and Z. The program utilizes all the major element data provided and calculates a solution from these data. i\lthough lower values for the sum of the squares of differences are generally better than higher values, the magnitude of the sum of squares of differences is not a statistical test of the goodness of the model. As the number of fractionating phases increases, the magnitude of the sum of squares of differences decreases. For example, although a model using mixing B, X, Y and Z will have a lower sum of squares of differences than a model using only B and X, this does not prove that the former model is better than the latter model. Also, when the number of the fractionating phases equals the number of major element oxides used in the analyses, the sum of squares of differences will be zero irrespective of all other factors. This is simply a consequence of the mathematical manipulation of the data. Hence, a sum of squares of differences of zero is not necessarily indicative of a perfect model. The problem of deciding on a maximum value of the sum of squares of differences for a plausible model can be solved by consideration of the possible 487 errors assiociated with the data used for the model (Carr, 1984). If the magnitude of the error in the data is taken at 3% relative, the possible error in SiO_ for samples with 50% Si02 will be 1.5 and the sum of squares of differences due to SiC_ alone will be 2.5. As the squares of errors in other constituents are small compared to the contribution of Si02, the maximum value fort he sum of squares of differences for a plausible model is based mainly on the Si02 content of the modelled components. The mean of a number of analyses of the composition of a mineral should be a better estimate of the composition than any individual analysis (Carr, 1984). Hence, in the Petmix calculations the average mineral analysis of each major unit were used as input data and listed below. Appendix 1-1. Oldest Ungaran Input data: Plagioclase Table 3-2 Clinopyroxene Table 3-3 Fe-Ti oxide Table 3-4 Amphibole Table 3-5 Olivine Table 3-6 Appendix 1-2. Old Ungaran Input data: Plagioclase Table 3-14 Clinopyroxene Table 3-15 Fe-Ti oxide Table 3-16 Amphibole Table 3-17 Olivine Table 3-18 I - ' 488 Appendix 1-3. Parasitic Cones Input data: Plagioclase Table 3-31 Clinopyroxene Table 3-32 Fe-Ti oxide Table 3-33 Amphibole Table 3-34 Olivine Table 3-35 Appendix 1-4. 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