PROVENANCE OF GLACIALLY TRANSPORTED MATERIAL NEAR NIMROD GLACIER, EAST ANTARCTICA: EVIDENCE OF THE ICE- COVERED EAST ANTARCTIC SHIELD
A THESIS SUBMITTED TO THE FACULTY OF THE GRADUATE SCHOOL ·OF THE UNIVERSITY OF MINNESOTA BY
Devon Michele Brecke
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE
May,2007 ACKNOWLEDGEMENTS
I'd like to thank my advisor, John Goodge, for the opportunity to pursue research
in the geological sciences. Thank you for the amazing experience to travel abroad and
explore the beautiful Transantarctic Mountains of Antarctica. Your guidance and support will always be appreciated. Thank you to Kathy Licht, Andy Barth, Emerson Palmer,
Peter Bradock, Kenn Borek Twin Otter flight support, and McMurdo Station personnel.
Without the hard-work and dedication of these individuals and the National Science
Foundation this project would not have been possible. I would like to thank my
committee members, Jim Miller and Paul Siders, for their interest and enthusiasm regarding this project. Thank you to the National Science Foundation, Geological
Society of America, University of Minnesota Duluth (UMD) Department of Geological
Sciences, and UMD College of Science and Engineering for funding to conduct and present this research. I am grateful for the support of many other individuals including
Howard Mooers (UMD), Karl Worth (Macalester College), Jeff Thole (Macalester
College), Ellery Frahm (University of Minnesota-Twin Cities Electron Microprobe
Laboratory), Val Chandler (Minnesota Geologic Survey), and the UMD faculty and staff.
Last, I would like to thank my family and friends for their on-going support, especially my parents who have always provided a loving home to return to after each adventure. ABSTRACT
Evaluation by glacial-clast petrography, igneous whole-rock geochemistry, metamorphic mineral composition, and magnetic susceptibility of glacially eroded, transported, and deposited material near Nimrod Glacier, East Antarctica provide information on the composition of the ice-covered East Antarctic shield. Precambrian basement of East Antarctica is only documented in the Transantarctic Mountains near the polar plateau of Nimrod Glacier, providing an ideal location to look for adjacent sub-ice
Precambrian terrain. Over 100 igneous and metamorphic rock clasts collected from moraines near the head of Nimrod Glacier show both local and transported material.
Physical characteristics of local rock fall show angular edges, whereas distantly transported material exhibits rounded edges, glacial striations, or rock types only seen upstream. Most metamorphic rock types collected show intense deformation fabrics, high-grade mineral assemblages, and high-grade P-T conditions, which are similar to the
Archean and Paleoproterozic Nimrod Group. Many igneous rocks may originate from either the Nimrod Group or from the syn-tectonic and post-tectonic Cambrian-Ordovician
Granite Harbour Intrusive series, and some come from nearby Ferrar dolerite (Jurassic).
These samples are compared to Cambrian-Ordovician rocks in southern Victoria Land, which differ in trace element trends. Although many of the clasts can be explained by local derivation, others appear exotic and may represent more distal origins in the shield interior. Future geochronology will help to refine the relative contributions of local and distal sources to test these conclusions.
11 TABLE OF CONTENTS
SECTION:
Acknowledgements I
Abstract 11
Table of Contents lll
Introduction 1
Background 4
Methods 19
Results 26
Petrography 26
Igneous Whole-Rock Geochemistry 33
Metamorphic Mineral Composition 44
Magnetic Susceptibility 59
Discussion 62
Conclusions 67
References 69
Appendix A: Petrographic Sample Descriptions 77
Appendix B: Igneous Whole-Rock Geochemistry XRF Data 107
Appendix C: Metamorphic Mineral Composition Electron Microprobe Data 112
Appendix D: Magnetic Susceptibility Data 117
lll LIST OF FIGURES: Page
Figure 1. Map of Antarctica 3
Figure 2. Radarsat image of study area 6
Figure 3. Geologic map of study area 7
Figure 4. Ice thickness map of Antarctica 14
Figure 5. Sub-ice topography near McMurdo Station, East Antarctica 17
Figure 6. Flow chart of rock types collected at primary site locations 27
Figure 7. Pie charts of rock types collected near Nimrod Glacier 30
Figure 8. AFM diagram 34
Figure 9. Geochemical data of moraine samples and Dry Valleys area 36
Figure 10. Geochemical data of moraine samples and Darwin Glacier area 37
Figure 11. Nb Harker diagram 39
Figure 12. Geochemical spider diagram normalized to chondrites 41
Figure 13. Ferrar-type geochemical spider diagram normalized to chondrites 42
Figure 14. Tectonic setting discriminant diagram 43
Figure 15. Backscatter images and element composition maps 46
Figure 16. P-T data for samples AGD, MRH, and MRJ 47
Figure 17. P-T data for samples AGE, AGG, and AGH 48
Figure 18. P-T data for samples MRT and TNE 49
Figure 19. P-T data for samples AGF, TNF, and KTF 50
Figure 20. Summary of P-T data 58
Figure 21. Rock type and magnetic susceptibility flow chart 60
IV LIST OF TABLES: Page
Table 1. P-T data of moraine samples 59
Table 2. Mineral composition of biotite 112
Table 3. Mineral composition of garnet 113
Table 4. Mineral composition of garnet continued 114
Table 5. Mineral composition of muscovite 115
Table 6. Mineral composition of staurolite 115
Table 7. Mineral composition of pyroxene 115
Table 8. Mineral composition of amphibole 116
Table 9. An content of plagioclase 116
v INTRODUCTION
The vast majority of Antarctica is ice covered, leaving 98 percent of the continental geology unmapped and unknown. Analysis of rock units exposed along the continental margin and geophysical surveys conducted over ice have enabled earth scientists to begin to understand the history of East Antarctica's major Precambrian shield, but such studies cover only a small area of the continent. The limited TAM basement represents the Pacific margin of the Archean to Neoproterozoic East Antarctic shield (Goodge et al., 2001). Sub-ice rock types in East Antarctica can be examined through analysis of glacially-transported rock material. This approach makes accessible a natural and random assortment of rock types once located under the East Antarctic ice sheet (EAIS). This method is more economical and logistically easier than drilling through the ice sheet and it can provide a more complete record of the sub-ice geology.
In addition, ice-scoured samples may provide material from a large area of ice cover, rather than just a few specific locations.
Glacially transported material can be evaluated in several ways:
1. characterize sediment compositions and accessory mineral suites in
glaciomarine sediment (Domack, 1982; Licht et al., 2005)
2. isotopic study of fine-grained glaciomarine materials (Farmer et al., 2003)
3. detrital-mineral geochronology, especially zircon, to determine age and
provenance signatures (Goodge et al., 2006)
4. petrologic, geochemical and geochronologic study of rock clasts in glacial
moraines (Peucat et al., 2002).
This study takes advantage of the rich record provided by glacial moraine deposits.
1 Moraine deposits are useful because they contain material that has been naturally removed from bedrock beneath the interior of the ice sheet, transported, and deposited on the surface. For example, Peucat et al. (2002) collected exotic rock clasts from moraine deposits along the Terre Adelie margin of Wilkes Land in East Antarctica and compared them petrologically, geochemically, and geochronologically to the Mezoproterozoic
Gawler Range Volcanics of South Australia. Results from this study showed evidence of similar rock types and ages in both areas, providing a more conclusive connection between the two continents prior to rifting. Their study demonstrates the effectiveness of using glacially-transported rock material in order to provide better constraints on subglacial Antarctic geology.
This study focuses on moraine samples collected from the Nimrod Glacier region
(Figure 1). Here the adjacent well-mapped basement outcrops represent the only known exposure of Archean rocks in the Transantarctic Mountains (TAM). Description of petrography, whole-rock igneous geochemistry, metamorphic mineral compositions, and magnetic susceptibility data from over 100 large rock clasts provides a foundation with which to compare moraine samples to mapped rock units.
2 O"
D CJ n Maud Land 0
Weddell Sea /\/\ 80°$ EAST /\ ANTARCTICA Pensacola /\ /\ Gamburtsev /\ Subglacial Mountains Mountains , /\ South 90' W - -+---+-- ---+----+---!- 90' E /\ 85'5 80'5 75°$ 70°5 WEST ANTARCTICA Aurora Subglacial Amundsen Sea Basin \ 'l Wilkes Land .. , f!.ictoria \. Land \ KEY /\ ? I\ t TAM Study D Area 180'
Figure l : Map of Antarctica illustrating geographic and subglacial areas of interest.
3 BACKGROUND
Study area and site locations
Study Area
The TAM mark the paleo-Pacific boundary of East Antarctica. The TAM are
held up by basement rocks of the early Paleozoic Ross orogen, including Neoproterozoic
metasedimentary rocks, a succession of lower Paleozoic sedimentary units, and Cambro-
Ordovician intrusions of a calc-alkaline batholith (Stump, 1995; Goodge et al., 2002).
Locally, in the upper Nimrod Glacier area, older crystalline basement rocks are exposed
that record an Archean and Paleoproterozoic history of the adjacent East Antarctic
cratonic shield (Borg et al., 1990; Goodge and Fanning, 1999; Goodge et al., 2001). All
of the basement units are overlain by a Devonian to Jurassic cover sequence (Beacon
Supergroup), which in tum is host to numerous mafic sills of the Ferrar Group (Barrett,
1986). The present-day physiography of the TAM is supported by differential uplift related to Cenozoic extension along a rift-shoulder flank (Barrett, 1986; Fitzgerald,
1994), accentrated by Holocene glaciation.
Major outlet glaciers within the TAM drain ice from the East Antarctic ice sheet to lower elevations at the Ross Sea. They continue to erode passages through this mountain chain and deposit transported rock in moraines. Among these outlets is Nimrod
Glacier (Figure 1), the second largest glacier to flow from East Antarctica's polar plateau into the Ross Ice Shelf. Nimrod Glacier is approximately 20 km in width and 150 km in length. The glacier drops 2, 100 m in elevation from its plateau threshold to the ice shelf, with a catchment area of about 152,000 km2 (Mcintyre, 1980).
4 This study investigates glacial deposits from the Nimrod Glacier region because this is the only location in the TAM where Precambrian basement is exposed and well studied, providing a clear foundation for petrologic and geochronologic correlations.
Additionally, this area is geologically well mapped (Grindley and Laird, 1969; Laird et al., 1971; Goodge et al., 1993a), allowing for distinction between local rockfall and transported material. Study oflarge clasts collected from Nimrod-area moraine deposits may therefore provide new information about the East Antarctic shield.
Site locations
Eight locations (Figure 2) near Nimrod Glacier comprise the primary and secondary sites for collected moraine material. Primary sites include those located at the head of the glacier, which contain a variety ofrock types, and a nunatak that is centrally located within Nimrod Glacier and hosts a large moraine with various rock types. Based on the variety of rock types and close proximity to the polar plateau, these sites are more likely to contain material transported from the sub-ice East Antarctic shield. Secondary sites include moraines that appeared to contain mainly local rockfall. These are located either at the head or along the side of Nimrod Glacier.
5 Figure 2: Radarsat image of study area (shown in Figure 1) near Nimrod Glacier. Primary moraines include Argo Glacier (AG), Milan Ridge (MR), Turret Nunatak (TN), and Kon-Tiki Nunatak (KD. Secondary moraines include Sanford Cliffs (SC), Quest Cliffs (QC), Gargoyle Ridge (GR), and Cambrian Bluff (CB). Base image from Canadian Space Agency.
Primary site locations for this study include Argo Glacier (AG), Milan Ridge
(MR), Turret Nunatak (TN), and Kon-Tiki Nunatak (KT). Clasts collected at these sites
were used for petrographic, petrologic, and geochemical analysis.
Secondary site locations include Gargoyle Ridge (GR), Cambrian Bluffs (CB),
Sanford Cliffs (SC), and Quest Cliffs (QC). Petrologic analysis was completed on select
clasts that were either representative of the site or showed unusual characteristics.
Geologic setting
Nimrod Glacier geology
Precambrian rocks in the Nimrod Glacier region are found in the Geologists and
Miller ranges (Figure 3) and play a critical role in understanding the history of the East
Antarctic shield.
6 160.E
Polar Plateau
83"5
• Beacon Supergroup (Devonian-Triassic)
• Granite Harbor Intrusives Ordovician) • Byrd Group silicalastic rocks (latest Early to Mlddle Cambrian?);Starshot Formation • Byrd Group carbonate &carbonate-clast rocks {lower Cambrian to Orovician); Shackleton Limestone &Douglas Conglomerate, undivided • Beardmore Group siliciclastic rocks (Neoproterozoic to Cambrian?) 0 TOO km D Nimrod Group metamorphic complex (Archean &Early Proterozoic) ---
Figure 3. Geologic map of study area with site locations from Figure 2 shown as dots. Modified from Goodge et al. (2004).
The Precambrian rocks, collectively called the Nimrod Group, contain banded
quartzofeldspathic to mafic gneiss, schist and quartzite, granitic to gabbroic orthogneiss, calc-silicate gneiss, relict eclogite, and pods of ultramafic rocks (Grindley et al., 1964;
Grindley, 1972; Goodge et al., 1993a; Peacock and Goodge, 1995). Prismatic zircon cores from a banded homblende-biotite gneiss in the Miller Range yielded SHRIMP U-
Pb ages of ca. 3094 and 2927 Ma (Goodge and Fanning, 1999), yet these rocks also experienced later geological activity at ca. 1700 and 500 Ma (Goodge et al., 2001).
Deformation fabrics in these rocks include pervasive well-developed L-S tectonite fabrics and mineral elongation lineation (Goodge, et al., 1992).
7 The Beardmore Group crops out east of the Miller and Geologists ranges and is thought to overlie the Nimrod Group. It is a rift-margin assemblage containing unfossiliferous sandstones, shales, carbonate, diamictite and minor volcanic rocks of Late
Neoproterozic age (Gunn and Walcott, 1962; Laird et al., 1971; Laird, 1981 , 1991;
Stump, 1982, 1995; Myrow et al., 2002). Unconformably overlying the Beardmore
Group is the Byrd Group. This sedimentary sequence consists of a basal marine transition (Holyoake Formation) passing upward to platformal Lower Cambrian
Shackleton Limestone, followed upward by the Douglas Conglomerate and syn-orogenic
Starshot Formation of shale, sandstone, and minor conglomerate (Laird, 1963; Myrow et al., 2002; Goodge et al., 2004a). These formations and the crystalline basement rocks are intruded by Cambrian-Ordovician granitoids of the Granite Harbour Intrusive series, a continental-margin arc suite, called the Hope Granites in the Geologists and Miller ranges
(Gunn and Warren, 1962; Gunner and Mattinson, 1975).
Devonian to Triassic deposits of the Beacon Supergroup, including sandstone, arkose, mudstone, conglomerate, and coal-bearing silt, unconformably overlie the basement rocks and are rich with terrestrial fossils (Barrett, 1986). Intruding the Beacon succession are Ferrar Group dolerite sills, which collectively extend along the entire length of the TAM and individually are up to 400 m thick in some locations (Gunn and
Walcott, 1962).
Rocks exposed in the Geologists and Miller ranges show deformation fabrics as evidence of tectonism attributed to the Nimrod Orogeny at ca. 1720 Ma (Goodge et al.,
2001) and the Ross Orogeny at ca. 540-480 Ma (Goodge and Dallmeyer, 1996; Goodge
8 et al., 1993b ). These events contributed to crustal development and displacement during the early history of the East Antarctic shield.
Although most studies recognize it as a key piece in the Rodinia and Gondwana supercontinents, East Antarctica's paleogeographic position during the Neoproterozoic and early Paleozoic is controversial. The paleogeographic position of East Antarctica differs among several Rodinia reconstructions, including: (1) Southwest United States-
East Antarctica (SWEAT; Moores, 1991), (2) Australia-Laurentia (AUSWUS; Karlstrom et al., 1999; Burrett & Berry, 2000) and (3) Australia-Mexico (AUSMEX; Pisarevsky et al., 2003). Recent evidence from detrital-zircon dating in the TAM supports the SWEAT association (Goodge et al., 2004b ), whereas some geological and paleomagnetic data support the AUSMEX model (Pisarevsky, 2003). These different models arose in part because of the few geologic constraints provided from Antarctica, illustrating the need for a better understanding of East Antarctic geology.
Geology ofprimary site locations
Argo Glacier geology
Argo Glacier (83.5°S 156.TE) is located in the southern Miller Range where outcrops consist primarily of the Precambrian Nimrod Group. This group was subdivided into the Miller Formation, Worsley Formation, Argosy Formation, and
Aurora Orthogneiss (Grindley et al., 1964). According to these workers, the Miller
Formation includes a layered sequence of polydeformed gneisses and schists, with lesser micaceous quartzite, marble, calc-silicate, and amphibolite; the Worsley Formation includes tremolite-bearing marble beds and gamet-biotite schist with contact
9 metamorphism from the Granite Harbour Intrusive series to produce diopside and cummingtonite in the marbles and andalusite-sillimanite in the schists; the Argosy
Formation includes gamet-biotite schists with intermittent layers of pasmmitic gneiss and minor quartzite, calc-silicate schist, marble, and amphibolite; and the Aurora Orthogneiss represents a mylonitized gneiss derived from a 1. 7 Ga granodiorite intrusion into nearby schist (Goodge et al., 1991; 2001). Additional rock types that occur in the Miller Range consist of the Granite Harbour Intrusive series, including granite, granodiorite, adamellite, and diorite (Grindley and Laird, 1969), and large mafic blocks containing eclogitic mineral assemblages (Grindley, 1972; Goodge et al., 1992; Peacock and
Goodge, 1995).
Milan Ridge geology
Milan Ridge (83.3°S 156°E) is located in the central Miller Range, approximately
25 km north of Argo Glacier. The geology at this location is similar to that of the Argo
Glacier region described above.
Turret Nunatak geology
Turret Nunatak (82.4°S 158°E) is located near the polar plateau on the west side of the upper Nimrod Glacier. The geology consists primarily of Beacon Supergroup strata and Ferrar Group dolerite sills. The Beacon succession there contains terrestrial quartz arenite and arkose, minor siltstone, carbonaceous beds, and conglomerate; the
Ferrar sills are tholeiitic quartz dolerite (Grindley and Laird, 1969). This region illustrates extensive intrusion of the Ferrar sills, demonstrated at the Laird Plateau where several sills of750 m thickness are exposed (Laird, 1971).
10 Kon-Tiki Nunatak geology
Kon-Tiki Nunatak (82.5°S 160°E), located in the middle of Nimrod Glacier, consists primarily of the Cobham and Goldie formations from the Beardmore Group.
The Cobham Formation includes regularly bedded marble, quartzite, and schist (Laird et al., 1971). The Goldie Formation lies conformably over the Cobham and includes meta- argillite and graded meta-sandstone with rare schist and marble beds (Laird et al., 1971).
Despite penetrative deformation and metamorphic recrystallization, many primary sedimentary features are preserved. The rock types and relict stratigraphic succession indicate these units represent shallow-water platform deposits of siliciclastic and calcareous origin (Cobham), overlain by deep-water turbidite sandstone and shale
(Goldie) deposited on a rifted margin (Laird et al., 1971; Goodge 1997). Metamorphism of these units produced a penetrative layer-parallel foliation in phyllites and schists, overgrown by poikiloblastic contact metamorphic minerals to form "spotted" textures
(Goodge, 1997).
Geology ofsecondary site locations
Gargoyle Ridge geology
Gargoyle Ridge (82.4°S 159.5°E) is part of the Cobham Range, located approximately 15 km west of Kon-Tiki Nunatak. The geology is comparable to Kon-Tiki
Nunatak and contains both the Goldie and Cobham formations discussed above. Granite
Harbour intrusions and Ferrar Group dolerite sills are found nearby in the Cobham Range and at Half Dome Nunatak (Grindley and Laird, 1969).
11 Cambrian Bluffgeology
Cambrian Bluff (82.4 °S 160.5°E) is located on the north side of Nimrod Glacier in the Holyoake Range. At this location, the geology consists of strongly deformed
Shackleton Limestone and Starshot Formation. The Shackleton Limestone contains primarily grey, white, cream and black limestone and dolomite, with additional thick layers ofbreccia and conglomerate, and minor quartzite, sandstone, and shale (Laird et al., 1971). The Starshot Formation contains graded fine conglomerate, sandstone and mudstone (Myrow et al., 2002).
Sanford Cliffs geology
Sanford Cliffs (83.9°S 158.9°E) is located at the head of Marsh Glacier in the
Queen Elizabeth Range. The geology primarily consists of Beacon Group with Ferrar
Group dolerite sills (Grindley and Laird, 1969).
Quest Cliffs geology
Quest Cliffs (82.5°S 154.8°E) is located in the Geologists Range. Precambrian
Nimrod Group rock types exposed in the Geologists Range include upper-amphibolite to lower-granulite facies interlayered pelitic schist, micaceous quartzite, amphibolite, banded quartzofeldspathic to mafic gneiss, homogeneous (garnet-)biotite-hornblende gneiss, granitic to gabbroic orthogneiss, calc-silicate gneiss and marble, migmatite, and relict eclogite (Goodge et al., 1993a; Goodge and Dallmeyer, 1996). Additionally, the northern Geologists Range contains Beacon Group strata intruded by Ferrar Group dolerite sills, and a small intrusion of the Granite Harbour Intrusive series (Grindley and
Laird, 1969).
12 Glacial geology ofEast Antarctica and Nimrod Glacier
Glacial history
Antarctica contains the largest ice sheet on Earth, which covers an area of 12.6 x
106 km2 with an ice volume of31.0 x 106 km3 (Bennett and Glasser, 1996). The ice is divided by the Transantarctic Mountains into two parts: the East Antarctic Ice Sheet
(EAIS) and smaller West Antarctic Ice Sheet (WAIS). Glaciation of Antarctica began approximately 34 Ma (Zachos et al., 2001) with the initiation of the EAIS. This extensive ice sheet now covers approximately 60% of the continent, contributing to the total continental ice coverage of 98%. Limited exposures of rock are found mainly near continental margins. These outcrops rise above the ice surface tens to hundreds of meters, extending to heights far above sea level. Ice thickness is reported to exceed 4,000 m in some locations (Elliot, 1985). Development of the WAIS did not occur until approximately 6 Ma (Zachos, 2001). This ice sheet is primarily grounded below sea- level and if the ice was melted an island archipelago would form (Elliot, 1985).
Growth of the main Antarctic ice cap during the Eocene is primarily attributed to changes in the Earth's orbital geometry and the reduction of atmospheric C02 (as cited in
DeConto and Pollard, 2003). Additional processes affecting ice cap development include the opening of the Tasmania-Antarctic Passage, followed by the opening of the Drake
Passage in the early Oligocene to create the Antarctic Circumpolar Current (ACC)
(Barker and Thomas, 2004). The opening of these deep ocean passages is commonly considered a secondary process, although debate continues regarding its timing (Barker and Thomas, 2004; as cited in DeConto and Pollard, 2003). In fact, Barker and Thomas
(2004) suggest the ACC may be a result of the glaciation in Antarctica, rather than a
13 cause. Regardless, these combined processes have helped maintain an environment that sustains massive ice sheets.
Moraine clasts are deposited near the TAM after entrainment and transport by ice.
An understanding of these glacial processes is essential for this study but is not the focus; therefore, only a brief discussion of glacial entrainment, transport, and deposition is described below. Clast transport distance is restricted to the size of the catchment area
(Figure 4; Hughes, 1998) and evidence of transport is provided by physical characteristics of clasts such as roundness or glacial striations.
O"
180" Figure 4. Ice thickness map (Lythe, 2000) showing Antarctica's glacier catchment areas (after Hughes, 1998). Origin for moraine clasts collected in this study are constrained to the Nimrod Glacier catchment area.
Glacial entrainment
Moraines may develop in various ways depending on the type of sub-ice material and the entrainment, transportation, and deposition mechanisms (Bennett and Glasser,
1996). Sediment entrainment by ice may occur through shear planes or folds, net freeze- on by conductive cooling, net freeze-on by glaciohydraulic supercooling, regelation
14 across basal obstacles, and regelation into basal sediment. Detailed discussion of these processes is provided by Alley et al. (1997). Of these entrainment processes, glaciotectonic simple shear and regelation are the most likely candidates responsible for the entrainment of basal sediments near Nimrod Glacier, although no studies have been done there to determine the specific mechanisms of sediment entrainment. The other processes are less likely due to the need for large removal of heat (net freeze on by conductive cooling) and water flow beneath the ice (glaciohydraulic supercooling) (Alley et al., 1997).
Glacial transport
The amount of entrained basal debris will directly impact the velocity of a glacier.
A higher concentration of material will increase frictional forces and slow down movement of the glacier (Bennett and Glasser, 1996). Entrained debris is transported in either the zone of traction or the zone of suspension. Material in the zone of traction will experience more abrasion and therefore show more roundness. The degree of roundness depends on the strength of the material and the distance of transport. Material being transported is constantly being worked to become more rounded, but it may also be crushed to form angular edges.
Whillans et al. (1989) describe glacial flow as being, "driven by gravity and ... restrained by forces acting at the bed or sides or by forces transmitted along the flow line." Researchers report the velocity of Nimrod Glacier is 298 m per year at a position 60 km downstream from Kon-Tiki Nunatak where the glacier is 18.3 km wide, with maximum ice depth of 960 m and total ice flux of2.2 km3 per year (Swithinbank,
1963; Harrison, 1970). No conclusive information is available to determine if Nimrod
15 Glacier is frozen to the bed. A study on the nearby Byrd Glacier, which flows 840 m per year (Swithinbank, 1963), predicts a frozen-bed condition, but could not exclude a thawed bed (Scofield et al., 1991).
The basal topography, along with the kind of sub-ice rock types, influences the glacier's entrainment and transport mechanisms. Bedrock topography beneath the EAIS can be constructed from aerogeophysical data. Studinger et al. (2004) constructed a topographic map of the subglacial terrain approximately 500 km north of Nimrod Glacier
(Figure 5). Their survey covered an area from the Ross Ice Shelf farther inland by 1150 km. They discovered that the TAM continue as a sub-ice physiographic feature approximately 400-500 km inland of the last exposed rock. Most likely, this sub-ice mountain profile continues towards the Nimrod Glacier region.
16 Ross Sea Polar Plateau
3 East Antarctic Ice Sheet a· E'2 Resolution Subglacial c Highlands 90"E ·.;:::;0 [;"' 0 iii V.E.= 30:1 -1 1 0 100 200 300 400 500 600 700 800 900 1000 1100 Km Figure 5. Sub-ice topography compiled from ice surface elevations and ice thickness estimates near McMurdo Station, East Antarctica (after Studinger et al., 2004). Sub-ice geology is interpreted from magnetic and gravity data (Studinger et al., 2004; Finn et al., 2006; Anderson et al., 2006). Profile (red line) is - 500 km from study area (star) as depicted in the inset map. Note bedrock surface is exaggerated by 30: 1.
,__...... :i Basal ice velocity and topography are the primary controls of the length of transport, as reported by Clark (1987). His study concludes that high sliding velocities result in long transport distances, whereas low sliding velocities result in short transport distances. Additionally, basal debris is more likely to be transported over longer distances through topographic lows than across intervening obstructions. It is clear from the sub-ice profile by Studinger et al. (2004) that the TAM provide large obstructions, which suggests that moraine deposition in the TAM may come primarily from a nearby source.
Glacial deposition
Glacial material may be brought to the surface by upward flow and thrust faults within the ice. Ablation of the ice surrounding this material allows for the deposition of transported material. In Antarctica sublimation from dry katabatic winds is the primary mechanism for ice removal and maximum net ablation for the nearby Byrd Glacier is predicted to be 0.2 m/yr (Scofield et al., 1991). As Nimrod Glacier encounters sub-ice mountain chains, the entrained debris is forced to the surface under compressional flow and then deposited. Moraines deposited closest to the polar plateau near the Nimrod
Glacier may therefore provide insight to Antarctica's geologic and glacial history.
18 METHODS
Field Methods
This study included the collection of large rock clasts from glacial moraine
deposits near Nimrod Glacier, located in the central Transantarctic Mountains (CTAM)
of East Antarctica. This area is ideal because it hosts the only known exposures of
Archean and Paleoproterozoic crystalline basement rocks in the CTAM. Additionally,
outcrops of Precambrian cratonic basement and adjacent younger Ross Oro gen
assemblages in the CTAM are well-mapped and can be used to establish differences
between distal glacially-transported material and local rock sources. A six-person field
party traveled to Antarctica during October and November of2005, where McMurdo
Station served as the base of operations.
Prior to field work, aerial photographs and topographic maps were studied in
order to identify candidate glacial moraine site locations. Potential sites were identified
on the basis of accessibility, abundance of surface moraine material, and proximity to the
head of the glacier. Priority sites included areas that would yield material derived from
beneath the ice cap, rather than from locally exposed rock units. Final site locations were
determined by in-flight surveys of moraine material, and as permitted by the landing
capability of the Twin Otter aircraft. Six moraine locations were sampled from the
Nimrod Glacier area completed during three day trips leaving from McMurdo Station.
Over 150 large clasts were collected near Nimrod Glacier. These samples were
collected by walking surveys of moraines with the intent of obtaining material not seen in
the surrounding exposed rock units, with the exception of a few site locations which
appeared to only have a local rock contribution. The majority of the rocks collected are I 19 of igneous and metamorphic types. Although statistically large sets of smaller pebbles were counted to determine the overall composition of transported clasts, specific rock types were collected as large clasts for petrologic analysis.
Initial classification of the collected samples was completed at McMurdo Station upon return from the field. Clasts were cataloged on the basis of their site location, individually photographed, and identified based on hand-sample petrologic characteristics. Approximately 50 rock samples were selected for transport to UMD by air in order to immediately begin preparation for thin section study. The remaining samples were returned to UMD by ship and domestic freight.
Petrography
Thin section petrography provides the primary basis for identifying rock compositions and mineral components. Igneous crystallization textures demonstrate the sequence of mineral formation, and mineral associations are used to address crystallization conditions and petrologic setting. Metamorphic recrystallization textures help to determine reaction history and protolith. Metamorphic mineral assemblages are used to estimate the physical (P-T) conditions of metamorphism. Petrography is the first step in identifying candidates for whole-rock geochemistry and geothermobarometry.
The glacially-derived clasts used in this study were sampled from the primary site locations of Argo Glacier, Milan Ridge, Turret Nunatak, and Kon-Tiki Nunatak (Figure
2). The first three sites are located at the head of Nimrod Glacier; due to their close proximity to the polar plateau, they are most likely to represent material derived from underneath the ice sheet. Kon-Tiki Nunatak is located midway along Nimrod Glacier and more likely contains local material. It may, however, contain material transported from
20 upstream areas beneath the polar plateau. Licht et al. (2006) provided evidence from glacial moraines for a non-local origin near the upstream head of the glacier, shown by an abundance of fine sediment, whereas deposition at Kon-Tiki Nunatak is considered to be more local. Thin sections were prepared for each of the large clasts collected at these locations.
The four remaining locations, Quest Cliffs, Sanford Cliffs, Gargoyle Ridge, and
Cambrian Bluff, showed a significant amount of locally-derived material. Therefore, only representative clasts or those with unusual characteristics were chosen for petrography and additional analysis.
Of 156 clasts collected from eight locations, 102 were selected for thin section study. Standard thin sections were made and petrographic descriptions of these are provided in Appendix A.
Whole-Rock Geochemistry
X-ray fluorescence was used to analyze the whole-rock geochemical compositions of selected igneous and meta-igneous clasts. Major and trace-element data obtained by this technique will help relate geochemical signatures to tectonic settings of magmatism. Major elements are used to determine overall magma evolution trends
(Winter, 2001) and trace elements provide information related to tectonic settings in which the magmas formed (Rollinson, 1993). These data are useful when examining possible relationships between the collected glacial samples and exposed basement rock units in order to address proximity to crustal sources.
Thirty-one rock samples were chosen for analysis based on their mineralogical and textural characteristics. These samples include all of the igneous rocks collected
21 from Argo Glacier, Milan Ridge, Turret Nunatak, and Kon-Tiki Nunatak, with the
exception of two clasts from Turret Nunatak due to the limited amount of sample material
available.
Samples were analyzed on the Philips PW 2400 x-ray fluorescence spectrometer
at Macalester College. Analyses of 10 major elements and 19 trace elements were
completed with help from Karl Wirth, Jeff Thole, and Dhiem Patel. The major elements,
reported as oxides, include: Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, and P. Trace elements
include: Sc, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Ba, La, Ce, Pb, Th, and U.
Several steps were completed to prepare samples for analysis. First, all weathered
surfaces were removed to provide a fresh sample. Due to the limited amount of available
sample material, approximately 60 ml of sample was selected to represent the whole-rock
analysis, depending on grain size to ensure that the analyzed sample is representative of
the rock. Second, a Braun chipmunk mill crushed the sample material into 0.5-1.0 cm
chips. Third, a SPEX 8510 shatterbox was used to powder the crushed sample material.
To avoid contamination during powder preparation, a tungsten carbide bowl was used to prepare the major element sample powder, while an iron bowl was used to prepare the
trace element sample powder. Thirty ml ofrock chips were placed in each bowl with 23 ml ofvertrel to aid in the removal of the powder when cleaning the bowls. Dried sample powders were then placed into two labeled sample bottles for major and trace elements.
Major-element analysis was completed on a fused glass bead, while trace-element analysis was completed on a powder pellet. The glass bead provides a homogenous surface for analysis, but it is diluted 5: 1 and the trace elements are unable to be detected; instead they were analyzed from a powder pellet.
22 Glass beads were prepared by measuring approximately 2 grams of powder that was dried overnight at 105 °C to remove surface water from the sample. The sample weight was then recorded and the samples were heated for an additional hour at 1000 °C.
The second heating step volatilizes any structural water and the Loss on Ignition (LOI) was reported as the percent weight change of the two sample weights, the difference reflecting the abundance of water in the sample.
A mixture containing 1.0000 +/- 0.0002 grams of dried sample, 5.0000 +/- 0.0002 grams of flux, and at least 0.01 grams of ammonium nitrate was placed in a platinum crucible to be melted. Two drops of hydrogen bromide was added to each crucible as a non-wetting agent, and then the crucible was heated. After a series of heating stages, the melted sample was poured into a mold. The glass bead was removed, labeled, and ready for analysis.
Powder pellets were made by combining approximately 10 grams of sample powder with 16 drops of polyvinyl alcohol. After mixing thoroughly, the sample was placed in a press at 6 tons pressure for one minute. The pellet was removed, labeled, and ready for analysis.
The major and trace-element analyses for each sample are listed in Appendix B.
The Geochemical Data (GCD) Kit (Janousek, 2006) was used for plotting and interpretation.
Electron Microprobe Analysis
Mineral compositions, determined by electron microprobe, allow for quantitative petrologic analysis of selected metamorphic rocks. Compositional data may be used with thermodynamically calibrated geothermobarometers in order to constrain pressure and
23 temperature conditions during formation, and allow for comparison with the histories of nearby exposed rock units (Goodge et al., 1992; Goodge, 2007).
Quantitative mineral analyses and compositional mapping were completed on a
JEOL 8900 electron probe microanalyzer (EPMA) in the Department of Geology and
Geophysics at the University of Minnesota-Twin Cities with help from Ellery Frahm.
Prior to analysis, photomicrographs of the probe samples were taken to provide sample maps and elemental composition maps were obtained to provide qualitative assessment of element zonation in minerals of interest.
Sample analysis by EPMA was completed by using an electron beam 5 µm in width and an accelerating voltage of 15 kV with 20 nA of current. Energy-dispersive spectrometry (EDS) was used for rapid mineral identification, while wavelength- dispersive spectrometry (WDS) was used for quantitative mineral analysis (Reed, 1996).
Appropriate samples were chosen based on their mineral assemblages for use in geothermobarometers and on evidence that illustrated textural equilibrium. For most samples I obtained qualitative garnet composition maps and quantitative analysis of garnet, biotite, and plagioclase. One sample, KTF, included a quantitative analysis of garnet and hornblende. Data from the 11 analyzed samples are listed in Appendix C.
Magnetic Susceptibility
Magnetic susceptibility was measured on all of the large clasts to record the intensity of remnant magnetization. The measured magnetic susceptibility of glacial clasts can be compared to aeromagnetic anomaly patterns and measured susceptibilities of rock outcrops in the Miller Range, and may help understand more about the origin of the glacially-derived material. Magnetic-anomaly highs, shown by aeromagnetic data
24 (Finn et al., 2006; Anderson et al., 2006), occur beneath the ice sheet and may be represented by the glacially-derived material collected at the head of the Nimrod Glacier.
Magnetic susceptibility was measured on 156 samples using a k-2 magnetic susceptibility meter on loan from the Minnesota Geologic Survey. The values recorded for each sample in Appendix D are an average of 10 measurements taken over the entire rock surface. Separate measurements were also taken for the weathered and non- weathered surfaces. In general, the non-weathered surfaces yielded a higher value, probably due to retention of primary magnetite. The higher value from fresh rock surfaces, when applicable, was used in further analyses because it represents a closer approximation of the actual rock magnetization. Reported values of the rock clasts in cgs units were converted to SI units in order to compare the glacially-transported materials with measured outcrops in the CTAM. The magnetic susceptibility can be used in conjunction with the previous methods to obtain a more complete understating of the rock types transported from the East Antarctic shield to their present occurrence as glacial clasts in the CTAM.
25 RESULTS
Petrography
Petrographic description of rock samples is necessary for rock type identification, classification, and selection of distinctive or representative rocks as candidates for further analysis. In this study, hand-sample identification of the large clasts provided an initial classification scheme; hand-sample classification then led to thin-section petrography for all rocks collected at primary site locations and select clasts, representative or unusual samples, from secondary site locations.
The focus of this study is to collect transported samples from ice-covered
Precambrian basement terrain. I did not make a comprehensive collection of rock types at each moraine, even though statistically-robust pebble sets were collected at each site.
Rather, I focused on rock types that are of particular interest because they are likely to represent basement material of the East Antarctic shield. At primary site moraines, not only did I focus on Precambrian rock types, but I purposely excluded rock types
Devonian or younger in age (Beacon or Ferrar). Samples from primary site moraines are described below and are arranged in Figure 6 by rock type and mineralogy. Secondary site moraines are likely from local origin and will not be focused on below. Sample descriptions from primary and secondary site locations are provided in Appendix A.
26 Rock Type
Gneiss I Amphibolite 11 Quartzite I I Marble! I Eclogitel MRZ TNN KTT MRT Grt-bt±ms Bt±ms Bt-amoh Other MRAA KTP AGE MRL AGQ AGN KTF KTQ AGG MRP MRI AGS AGH MRV MRQ KTE AGI KTS MRR KTV AGJ KTX MRY MRAB KTI Metamorphic MRAC KTY MRG MRO MRW MRX KTL KTM KTN KTO KTU
I Granodioritel I Leucodiorite 11 Monzodiontel I Qtz monzodioritel I Dolerite I MRU KTAA KTAB KTAE AGL Tour-ms-bt,, ···- -- , AGM TNK MRF TNR MRK TNS MRM Igneous KTAC MRN TNH
I Sandstone! I Diamictite ] Sedimentary TNI TND KTD
Figure 6. Rock types collected at primary site locations arranged by petrographic characteristics. Samplesdesig-nated-by location: AG=Argo Glacier; MR=Milan Ridge; TN=Turret Nunatak; KT=Kon-Tiki Nunatak. Mineral abbreviations are as follows: Als=Aluminum silicate polymorph; Grt=Gamet; Bt=Biotite; Ms=Muscovite; Tour-Tourmaline; Amph=Amphibole; Qtz=Quartz. Italics indicate ianeous rock tvoes that show foliation. N --..:i Metamorphic rocks are the most abundant rock type collected. The majority of these are gneisses and schists, similar to lithologies in the Nimrod Group. Several of these rocks contain an aluminum-silicate polymorph, commonly sillimanite, which indicates high temperatures and/or pressures. Garnet and biotite are commonly present in the mineral assemblage.
Additional metamorphic rock types include phyllite, amphibolite, quartzite, marble, and eclogite. Samples unique to the collected suite include sillimanite- muscovite-biotite quartzite (KTQ) and eclogite (MRT). KTQ is a high-grade aluminous quartzite that shows mica-pinning microstructures and has not been documented in the nearby geology.
MRT shows unique physical characteristics in hand-sample as well as in thin- section. The rock's rod-like shape and well-rounded edges are evidence of glacial transport, supported by glacial striations on the surface. It is a dense, dark-colored and fine-grained rock containing garnet porphyroblasts. In thin section, the garnets are broken and surrounded by plagioclase and clinopyroxene symplectites. The globular appearance in the symplectite texture indicates a decrease in pressure during metamorphism (Joanny, 1991), suggesting a retrograde process. It is likely to be a retrogressed eclogite.
Granites and dolerites comprise the most abundant igneous rock types collected.
Granites are subdivided by the presence or absence of macroscopic foliation as seen in hand-sample. However, intrusion of the Granite Harbour rocks occurred both during
(540-520 Ma, Goodge et al, 1993b) and after the Ross Orogeny (500-475 Ma, Gunner and Mattinson, 1975) leading to deformation fabrics in younger rock types. Because the
28 age of the foliated rock types cannot be distinguished in hand-sample, all foliated rocks are associated with the Nimrod Group. In general, foliated rock types are pinkish in color, whereas the non-foliated rock types are light gray and contain a mineral assemblage of muscovite + biotite ± tourmaline, as is common in the Granite Harbour suite. Granodiorite (MRU) and monzodiorite (KTAB) are non-foliated granitoids that may also be associated with the Granite Harbour suite.
A common rock type collected at both primary and secondary site locations is dolerite. These rocks are generally fine-grained dark mafic rocks with a sub-ophitic texture of plagioclase and clinopyroxene. They are compositionally and texturally similar to Ferrar Group dolerite occurring in numerous sills in the area.
Leucodiorite and quartz monzodiorite are distinctly different mineralogically and texturally from all other samples. Biotite leucodiorite (KT AA) has a unique blotchy texture formed by black (biotite) and white (quartz and feldspar). Biotite-hornblende quartz monzodiorite (KTAE) contains large feldspar phenocrysts surrounded by a black fine-grained matrix showing internal foliation. Both clasts have well-rounded edges, suggesting glacial transport.
Sedimentary rock types can be correlated with younger units exposed near the sample sites and, therefore, only a few were collected. Primary site locations yielded the collection of three sedimentary rocks that consist of two sandstones and one diamictite.
A sandstone (KTD) is unique because it is a very dark fine-grained rock that shows weak metamorphism along with relict bedding.
Based on petrographic analysis, the 90 samples collected at primary site locations are divided into five groups. The largest and most diverse includes 49 metamorphic
29 rocks and 11 foliated igneous rocks. These rocks are grouped together because they show deformation fabrics and/or high-grade mineral assemblages. The second largest group contains 11 non-foliated granitoids, followed by the third group with 10 low-grade metamorphic schists, phyllites, a quartzite, and a meta-sandstone. Group four contains 7 dolerites, and group 5 contains two sedimentary rocks.
Rock types collected at each site location are shown in Figure 7. The pie charts
• • Nonioiated granitoids
. Limestones.marbles.shales
Figure 7. Rock types collected near Nimrod Glacier from primary site locations (large pie charts) and secondary site locations (small pie charts). Colors represent different rock types that correspond to geologic units shown in Figure 3, but this does not mean that the clasts were derived by glacial erosion from those units. Byrd Group is all light blue and Ferrar Group is orange. Base image from Canadian Space Agency. do not represent all rock types seen at the moraines. I focused on samples possibly derived from an older Precambrian source, so only those rock types collected are shown
30 in Figure 7. Statistically-representative large populations of pebbles were counted from
multiple grid areas at each site in order to determine the overall rock-clast proportions
(Licht et al., unpublished data). The different colors correlate with rock types which may
be derived from, or are similar to, exposed geology (Figure 3). Primary site locations
contain high-grade metamorphic rocks, non-foliated granitoids, low-grade metamorphic
rocks, dolerite sills, and sedimentary rocks. Secondary site locations contain non-foliated
granitoids, elastic and carbonate sedimentary rocks, and dolerite sills. High-grade
metamorphic rocks are only found at primary site locations and, therefore, only these
sites are described further.
Samples collected at Argo Glacier and Milan Ridge are primarily high-grade
metamorphic rock types with few dolerites and non-foliated granites at Argo Glacier. All
of these rock types are similar to local geology and may or may not have been derived
from under the ice sheet. Several clasts do show rounded edges or glacial striations,
suggesting a sub-ice origin, while few show more angular edges as evidence for a local rock fall source.
Turret Nunatak samples show the largest variety in rock type. Collected samples include high-grade metamorphic rocks, non-foliated granitoids, low-grade metamorphic rocks, dolerite sills, and sedimentary rocks. Local geology does not include the high- grade metamorphic rock types collected at this location. Several samples show evidence for glacial erosion, while others do not.
High-grade metamorphic rocks, foliated igneous rocks, and non-foliated igneous rocks are found in the moraine along Kon-Tiki Nunatak. This moraine extends for more than 4 km along the nunatak margin and contains a wide variety of rock types, allowing
31 for collection of specific rock types that may be Archean or Paleoproterozic in age. The exposed geology at this nunatak consists of low-grade metamorphic schists, phyllites, marbles, and quartzites. Twenty-six of the 31 rocks collected at the Kon-Tiki moraine are not among these rock types and, therefore, must have been transported some distance by the glacier. The Kon-Tiki clasts could represent rock types originating from high- grade Precambrian rocks in the Geologists and Miller ranges (Nimrod Group), or perhaps they are derived from beneath the EAIS.
Evidence of glacial transport in hand-sample includes rounded edges and glacial striations. Material encased in ice is constantly eroded to produce rounded edges, only to be crushed and the process repeated. Rocks that show rounded edges are likely to have been carried by ice, whereas those that show more angular edges may or may not have been contained within ice during transport; angular clasts could represent local rockfall carried on top of or as lateral moraine debris at the margin of outlet glaciers. Rod-shaped clasts provide the least resistance when transported by ice and orient themselves parallel to ice flow. A variety of shapes and degrees of roundness are found at primary site locations, different from secondary site locations that show primarily local angular rock fall. In general, primary moraine sites reflect both erratic rock types and local geology, while secondary moraine sites only show contributions of local geology.
32 Whole-Rock Geochemistry
Igneous whole-rock geochemical data provide a way to compare igneous moraine clasts of unknown origins to known rock types from the TAM. Discrimination diagrams help to identify trends within suites of samples to learn more about magma crystallization and fractionation processes, as well as tectonic settings. Discrimination diagrams are useful, however Rollinson (1993) notes that they are intended for suites of possibly cogenetic samples rather than individual samples or groups of unrelated samples. Due to the natural mixing process in glacial transportation, moraine samples are rock types from multiple unknown sources, limiting interpretations of their sources or origins. It is possible, however, to identify calc-alkaline or tholeiitic trends on AFM (alkalis, iron, magnesium) diagrams, anomalies of major and trace elements on binary plots, and trace- element trends on so-called spider diagrams. Data from collected rock types are compared with known sample suites of granitoids in the TAM to help identify samples derived from the Ma Granite Harbour Intrusive series and Jurassic Ferrar dolerites.
Samples with compositions outside of these two main groups may therefore represent older igneous lithologies of the East Antarctic shield that would be good targets for further study and geochronological analysis. I used the GCD kit (Janousek et al., 2006) to generate plots used in this study; major and trace element data are listed in Appendix
B.
Under hydrothermal and metamorphic conditions certain trace elements may become mobile. In general, low field strength elements such as Cs, Sr, K, Rb, and Ba are mobile, while high field strength elements including Sc, Y, Th, Zr, Hf, Ti, Nb, Ta, and P
33 are immobile (Pearce, 1983). Additionally, mobile transition metals include Mn, Zn, and
Cu, while immobile transition metals include Co, Ni, V, and Cr.
In this study, 27 igneous rocks and 4 metamorphic rocks that show igneous mineralogy, texture, and protolith were examined for their geochemical patterns. All rock types were collected from primary site locations and some samples show foliation and/or lineation. The focus of this study is to make comparisons between collected moraine samples and known outcrops, assuming that geochemical signatures should be consistent among rocks from similar origins.
AFM diagrams are used to distinguish between calc-alkaline and tholeiitic series magmas (Figure 8; Irvine and Baragar, 1971). Both series are represented in this study, with the tholeiitic series likely representing the Ferrar Group (Hanemann and Viereck-
Gotte, 2004). The remainder of the samples are calc-alkaline, with several of alkaline composition.
F
Cale-alkaline Series
A M Figure 8. AFM diagram showing two different trends among the collected clasts (boundary between tholeiitic and calc-alkaline fields from Irvine and Baragar, 1971 ). 34 Harker diagrams are binary plots that show magma chemical evolution within
sample suites. Samples from this study may represent several unrelated magmas and,
therefore, Harker diagrams are used to identify anomalous element concentrations,
compare data with known igneous rocks in the TAM, and perhaps identify rocks from
similar parent magmas. Samples that are chemically similar to Ferrar Group are not
included in the Harker diagrams here because of their distinctly different and known
origin. Sample data of granitic rocks are plotted together with published data from the
Dry Valleys area in southern Victoria Land (Figure 9) and the Darwin Glacier area in
southern Victoria Land (Figure 10). The published data in these figures are enclosed within ellipses. Multiple ellipses are used to better define published data trends. These data are used to evaluate correlation with known Granite Harbour rocks.
35 22 KTAA 3.0 700 A,!'T MRP 21 2.5 1800 . • KTAO Ab03 600 Rb 1600 Sr l MRO 20 2.0 INS . 500 MRY 19 TNR • • • TNK 1400 1.5 18 0 •KTAC 1200 17 1.0 TNG• Q I • KTK 300 1000 16 0.5 KTW 15 0 200 800 14 Na20 Kl)VI 6 I 100 \ . .•/ 600 13 I !ITT - . 0 400 12 AGJ KTAO 5 • 11 35 Cr 200 KTAf; I 4 30 . 6 t I I 0 s t "\. / •.•• I I 3 .. 20 100 4 t / . . / I 2 15 80 •MRY 3500 Ba 10 60 5 40 L/K20 3000 KTAA I 0 20 •MRP •lNQ 2500 KTK• 90 y \...CU 0 6t- I 80 KTAE•n 2000 70 500 60 400 50 1500 40 300 1000 •MRE ! 30 :[ 200 ·'\ 500 (. 20 10 100 0 . 0 0 65 70 75 80 60 65 70 75 80 60 65 70 75 80 60 65 70 75 80 Si02 Si02 Si02 Si02 Figure 9. Whole-rock igneous geochemical data illustrating glacially transported moraine samples (individual points) and granitoid data from Dry Valleys area, southern Victoria Land, East Antarctica (enclosed within ellipses; Allibone et al., 1993). \.>) °' Figure 10. Whole-rock igneous geochemical data illustrating glacially transported moraine samples (individual points) and granitoid data from Darwin Glacier region in southern Victoria Land, East Antarctica (enclosed within ellipses; Simpson and Cooper, 2002).
37 The two published data sets come from nearby areas in southern Victoria Land of
the TAM and show similar results. Both studies show distinct chemical signatures from three different batholiths. The Dry Valleys area study includes more individual rock
analyses, resulting in larger ellipses than the Darwin Glacier suite and, therefore, the Dry
Valleys suites are used in comparisons below, with the exception ofTi02 and Ga values
from the Darwin Glacier suite.
Most of the analyzed granitoid samples show major-element variations that are similar to Granite Harbour-type patterns shown by the Dry Vallyes and Darwin Glacier suites, with exceptions noted here. Biotite leucodiorite (KTAA) and muscovite-biotite monzodiorite (KTAB) consistently plot outside of published data. In general, they lie on the same trend, but with lower silica contents (-60 wt%). This pattern is seen for the following elements: Ti02, Fe20 3, Na20, Ga, Sr, Ah03, K20, CaO, MgO, Ba, Rb, and Sr.
Other samples plot outside of the published data ranges for Ti02, Ga, Ba, Sr, Rb,
Y, and Cr. Biotite-hornblende quartz monzodiorite (KTAE) lies approximately 0.3 ppm
(-50 %) above the Ti02 published data. Tourmaline-muscovite-biotite granite (KTAC) shows an approximate 5 ppm increase (-50 % higher) in Ga over the Darwin Glacier granites.
Biotite-hornblende gneisses (MRQ and MRY) are over 1000 ppm higher in Ba than Dry Valleys granites. These samples are also greater than 400 ppm above, nearly double, the published Sr data. Elevated Sr levels are also observed in muscovite-biotite gneiss (MRP) with a value of 1665 ppm, almost 700 ppm over the published data. High
38 Sr levels were also found in homblende-biotite granites (KTK and MRD) muscovite- biotite granites (AGK and MRE).
Three tourmaline-biotite-muscovite granites (TNR, TNS, and TNK) plot very close to each other, 200 ppm higher Rb than Dry Valleys granites. Tourmaline- biotite-muscovite granite (KTAC) and muscovite-biotite granite (KTAF) plot near each other with smaller, but distinctly elevated Rb levels of ppm and ppm, respectively. Gamet-muscovite pegmatite (AGT) shows very high Rb values nearly 400 ppm greater than published data.
Muscovite-biotite granite (TNQ) and biotite-homblende granite (KTAD) are 25-
50 ppm higher in Y relative to Dry Valleys granites. KTAD also shows elevated levels
ppm) of immobile Nb when compared to the collected moraine suite (Figure 11).
35 e KTAD Nb ,_ 30
25 .... TNQ KTK eMRY •• 20 - eMRQ eMRD e KTAE eTNG 15 - • •KTAS eAGJ • 10 - • MRU• • ••••• 5 eMRP eKTW
•KTAA 0 60 65 70 75 80 Si02
Figure 11. Nb Harker diagram illustrating similarities among moraine samples and the elevated NB value of KTAD.
39 Sillimanite-muscovite-garnet-biotite gneiss (AGJ) is over 10 ppm higher in Cr than published data. One explanation for Cr increase in AGJ is due to substitution of Cr into the crystal lattice of sillimanite, muscovite, or garnet.
Harker diagrams help to identify samples that show differences among the collected moraine suite and published granitoid data. Additionally, these diagrams help to recognize samples that are nearly identical to each other, such as biotite-hornblende gneisses (MRY and MRQ) and tourmaline-biotite-muscovite granites (TNK, TNS and
TNR).
Chondrite-normalized spider diagrams illustrate trace element patterns. Moraine samples are arranged into five groups based on similar trace element pattern and magnitude (Figures 12 and 13). These groups do not necessarily correlate with commonalities or differences seen in Harker diagrams. They are the best fit of similar trace element trends. In general, the moraine samples show enrichment in mobile elements with concentrations up to 1OOOx chondritic and uniform immobile element concentrations and lower (10-1 OOx chondritic ).
40 10000 10000 a ······· .. KTAD KTAE --- TNG t. ..--- ...... MRY - ·-·· KTAC /: -·- ·· MRQ 1000 1000 ./A I..... ·;:: ==- .. - .. _ TNR ·;:: == -g -----· AGT -g 0 100 0 100 .s:: .s:: I ,-\,...... v v . E 10 E 10 ro . ro Vl Vl
0.1 0.1 I I I I I I I I I I I I Ba RbTh K Nb La Ce Sr p Zr Ti y Ba RbTh K Nb La Ce Sr p Zr Ti y 10000 10000 b ••••••••• MRU •••••• •• • AGK --- KTAB --- MRD -·- .. TNQ -·-·· MRE 1000 -- KTZ v _ ,, _ .. _ KTAF 1000 /\ -- MRP v ------KTJ ·;::... ,-';······ _ ,, _ ,, _ KTW "O ·;::... c: "O 0 c: { -----· KTAA 100 0 100 _;- .s:: .s:: u...... v v E 10 10 ro E Vl ro -...... Vl
0.1 I I I I I I I I I I I I 0.1 -t-...---.---.--..----.---..---.----r--.----.-----l Ba Rb Th K Nb La Ce Sr p Zr Ti y Ba RbTh K Nb La Ce Sr p Zr Ti y Figure 12. Whole-rock igneous geochemistry of trace elements normalized to chondrites (Thompson, 1982).
..j::. Samples are grouped by similar trace element magnitudes and patterns. Gaps within sample patterns represent - trace element values below detection levels. 10000 .------;::::===:::;i •·•·•••·• AGL Ferrar-type --- AGM -·- ·· MRF 1000 -- MRK ------MRM - ··- ··- MRN -----· TNH
0.1 Ba Rb Th K Nb La Ce Sr P Zr Ti Y Figure 13. Whole-rock igneous geochemistry of trace elements normalized to chondrites (Thompson, 1982). Samples are from the Ferrar Group.
TNK, TNS, TNR, KTAC, KTAD and muscovite-biotite granite (TNG) are
grouped together based on similar trace element magnitude (Figure 12a). Compared to
one another they show similar trends, but KTAD stands out because of large difference in
concentration.
Muscovite-biotite granites (TNQ, KTZ, KTAF) garnet-muscovite-biotite
granodiorite (MRU) and muscovite-biotite monzodiorite (KTAB) show only slight
changes in trend or magnitude (Figure 12b). TNQ shows elevated values in La, Ce, Zr,
and Y, while KTAF shows a distinct decrease in P and Y.
MRQ, MRY, KTK, KTAE, and AGJ show a very similar pattern with slight
variation in concentration (Figure 12c) while immobile Zr, Ti, and Y values are similar.
In general, AGJ is unique with lower trace element values.
AGK, MRD, MRE, KTAA, muscovite-biotite gneiss (MRP), biotite granite (KTJ) and muscovite-biotite granite (KTW) all show a similar pattern in P, Zr, Ti, and Y, but
42 not in the remaining elements (Figure 12d). Element magnitudes vary in all elements, especially P. The gap seen in KTAA is due to Th concentrations below detection levels.
Rocks that represent the AFM tholeiitic series show a very uniform trace element trend and magnitude (Figure 13). As noted above, these samples are likely from the
Ferrar Group.
Trace element data may also be used to interpret tectonic settings of magmatism.
Pearce et al. (1984) showed that a combination of mobile and immobile elements can be used to discriminate different tectonic settings of granitoid magmatism. Trace-element data from this study are shown on a plot of Rb vs. Nb+Y (Figure 14), which separates fields of volcanic-arc, intraplate, and syn-collisional occurrences.
1000
AGT TNS 0 500 Syn-collisional. TNR• • TNK KTAF Rb • (ppm)200 KTAC
• 100 Intra plate Volcanic arc AGJ KTAA • 50 • 5 10 20 50 120 Nb+Y(ppml Figure 14. Tectonic setting discriminant diagram comparing moraine collected samples with granitoids from the Dry Valleys area (Allibone et al., 1993 ). Fields for tectonic settings from Pearce et al. (1984).
Published data from the Dry Valleys fall primarily into the volcanic-arc setting. These data also extend into the intraplate setting with a few showing affinity to syn-collisional settings. Most data points from this study lie within the volcanic arc setting. Biotite-
43 hornblende granite (KTAD) and muscovite-biotite granite (TNQ) extend into the intraplate setting, just beyond the published data. Both of these samples also show unique spider diagrams.
Samples TNK, TNS, TNR, KTAC, and KT AF show affinities to syn-collisional granites and have elevated Rb levels relative to Dry Valleys granites. Mineralogically and texturally these samples are very similar to the Granite Harbour Intrusive series seen in the central TAM. Petrographic evidence for feldspar alteration to sericite may be an indication of Rb mobilization, although Rb enrichment in these samples is up to 300 ppm greater than Dry Valleys granites.
A few samples are similar to A-type (anorogenic) granites based on geochemical data (Whalen, 1987). Samples that often plot within the A-type granite field include:
MRD, MRQ, MRY TNG, TNQ, KTK, KTW, and KTAD .
Mineral Compositions
Mineral composition data used in conjunction with calibrated geothermobarometers allows for quantitative interpretations of P-T conditions during metamorphism. Geothermobarometers use the temperature and pressure dependence of the equilibrium constant (K) associated with mineral reactions, measured from coexisting minerals in a sample, to determine the metamorphic pressures and temperatures of equilibration (Spear, 1993).
Geothermometer calibrations are based on cation exchange reactions with small volume change, while geobarometer calibrations are based on net transfer reactions with large volume change (Spear, 1993). Geothermobarometers used in this study include garnet-biotite (GB), garnet-hornblende (GH), and garnet-clinopyroxene (GCPX)
44 geothermometers, and the gamet-aluminosilicate-silica-plagioclase (GASP) geobarometer. This study analyzed 11 moraine samples for mineral compositions including 7 gneisses, 2 phyllites, 1 amphibolite, and 1 eclogite.
Most geothermobarometers use garnet because it is a 4-component solid solution and because it may preserve different stages of metamorphic growth by compositional variation from the mineral core to rim, as seen in Figure 15. Mineral composition profiles (Figures 16-18) show zoning or reflect changes in Fe, Mg, Ca, and Mn across the mineral. These relationships provide evidence for changing composition in response to pro grade or retrograde metamorphism. Also, in most cases garnet shows small proportions of Ca and Mn, so that their compositions can generally be treated as simple
Fe-Mg binary solid solution.
45 AGE
TNE
MRT
Figure 15. Backscatter images (a,c,e) and element composition maps (b,d,g) for garnets used in geothennobarometry calculations. Backscatter images show transects of the garnet profiles in Figures 17 and 18. MRT backscatter inset image (f) is a close-up of plagioclase and clinopyroxene symplectite from outlined area. Light areas in the composition maps represent enrichment of the indicated element.
46 AGD garnet MRH garnet MRJ garnet 2.51 a g g a a 2 _t ···...... []n 2t. []n ...... ·- ...... c ...... a 1.5 1.5.t t t t I 0 11- 1 t------1 ------·------n _,,- s __ --·------/ "" a.st - 0.51- - 0.5 ..
I- . • . . ------· -·· ------a..- ----· -- - ·--- - ·------·--··- Rim ...,.....____ -1 mm )ii Core Rim ...ll(i--- -1 mm )ii Core Rim ...II(,..--- -1 mm )l Core
AGD MRH MRJ 10 - 161 b d f 14 8 8 12 p10 k 6 6 ; .... Ky Ky ... ;" J •"' b 8 ,/ I Sil ,,,,,,, \". I...... v•.,. , ,.. a 6 . .,," ·.. ,.... ; ...... r An.)l" .,.. / ,,· .,. ,_;;:: ·- .- ,,,,.,,,,.,. ... ·· ..-;. ( " Core · ·.:-> -- Rim I ,..-"
400 500 600 700 800 900 1000 400 500 600 700 800 900 400 500 600 700 800 900 T·c T'C T'C
Figure 16. Garnet profiles (top row) from rim to core of Fe, Mg, Ca, and Mn cations per formula unit. Small arrows show the location of analyses used in the following calculations. P-T plots (bottom row) generated by GTB software (Spear and Kohn, 2006) show Ferry and Spear (1978) GB geothermometer results and Newton and Hasselton (1981) GASP geobarometer results. Solid lines indicate analyses taken from garnet cores, while dashed lines are from garnet rims. Shaded areas indicate observed mineralogy . ..j:::.. -...) AGE garnet AGG garnet AGH garnet 2.51 a 2.5. c 2.51 e 21- [J···Fe 2 .. 1-----·MgFel ··•\ -- Mg t '. :-... ······. -·-Ca ·····- ••• .. - ·- Ca c 1. 5 :: . '... :' '1 \ ··--·-·······-····-··- +·····Mn 1 5 ...... / · : • - M a . ····+··· :' ...... · ...... t i L ___ ,,...--, 0 1 11- 11- n r ---.... ·--·----, s • ·-..1 \.. ..,. / ...... /.-- ______( - 0 Sr- , • ..- · -·--...... _ 0.5 . ....- .-----,.. .. / 0.51-/ \ '\· --\ . ______•' ·, . ------... . Rim -1.5 mm > Rim Rim -0.5 mm > Core Rim -1.5 mm >Rim A A'
AGE AGG AGH 10 14 I b m I m 1 I 12 f 8 I I p I 10 I k 6 6 I 8 b Ky I 6 a 4 !.....< Sil r 4 2 2
400 500 600 700 800 900 400 500 600 700 800 900 400 500 600 700 800 900 T"C T'C T"C
Figure 17. Garnet profiles (top row) from rim to core or rim to rim of Fe, Mg, Ca, and Mn cations per formula unit. Small arrows show the location of analyses used in the following calculations. P-T plots (bottom row) generated by GTB software (Spear and Kohn, 2006) show Ferry and Spear (1978) GB geothermometer results and Newton and Hasselton (1981) GASP geobarometer results. Solid
..J::>. .__lines______indicate analyses taken from garnet cores, while dashed lines are from garnet rims. Shaded area indicates observed mineralogy__, . 00 MRT small garnet MRT large garnet TNE garnet 3 3 g g 2 .5L c •• ·••••· -- MgFe 2.5La a a ········· ••••••• ·[J···- ·-·Ca [Jn [Jn 2 ------·-- - Mo 2 ...... _. ! ...... / ...... \ .... . c 2 r·····-. ..---- ______·-----· -----·· ...... 1.5 I 1. 5 t ------T 1.5 --r not used in T analyses n 1 s 1 1 1,.- ...... - ... -:: ·J·-·..t.:- · 0 .5 1--:·---·-.. - .--- ·-· ---·-- .--- 0 . 51'"..r ·- · . - - -- 0.5 ------..--: .=--..- .:-_.::-- :::- Rim ii( - 0.5 mm )lo Rim Rim ii( - 1.5 mm )lo Core Rim ii( - 1 mm )ii Core A A' B B' A A' MRT (GB) MRT (GCPX) TNE 10 FCofel 10 Coe 10 / FCofel b I d f I I - 79 I
p 8 VI' 8 8 I I k 6 6 6 I I b Ky I Ky I I 4 4 I r _..-<1'. si1 2 2
I j I I 400 500 600 700 800 900 400 500 600 700 800 900 400 500 600 700 800 900 T·c T'C T'C Figure 18. Garnet profiles (top row) from rim to core or rim to rim of Fe, Mg, Ca, and Mn cations per formula unit. Small arrows show the location of analyses used in the following calculations. P-T plots (bottom row) generated by GTB software (Spear and Kohn, 2006) show Ferry and Spear (1978) GB geothermometer results (band t) and Ellis and Green (1979), Powell (1985), and Pattison and Newton (1989) GCPX geothermometer results (d). MRT small garnet data is used for all MRT calc4lations. Solid +:- lines indicate analyses taken from garnet cores, while dashed lines are from garnet rims. \0 AGF TNF KTF a 10fb 8
6
4L. Sil
400 500 400 500 600 700 800 900 550 650 750 850 950 1050 T °C T"C
Figure 19. No garnet profiles were obtained due to small garnet size (<0.5 mm rim to rim) and very irregular shape. Analyses used in the following calculations are average data points throughout the garnet. P-T plots generated by GTB software (Spear and Kohn, 2006) show Ferry and Spear (1978) GB geothermometer results (a and b), Graham and Powell (1984) and Perchuk, et al., (1985) GH geothermometer results (c), and Newton and Hasselton (1981) GASP geobarometer results (a). Shaded areas indicate observed mineralogy.
Vl 0 Analysis of eleven garnet-bearing samples by electron microprobe generated
elemental oxide data for garnet, plagioclase, biotite, muscovite, amphibole, pyroxene, and
staurolite. These values, along with calculated cation proportions, are reported in
Appendix C. Each reported value is the average of three to nine individual spot analyses,
after elimination of outlier data points. Biotite analyses were obtained from matrix grains
nearby the analyzed garnet or from inclusions in garnet when possible. Generally, matrix
biotite compositions were associated with garnet compositions measured near rims to
obtain "peak" metamorphic conditions; the compositions ofbiotite inclusions were
associated with garnet composition measured in the core region to assess prograde
conditions. Some biotite compositions inside the garnet were not used because of
chlorite alteration. Plagioclase compositions were determined from microprobe data by:
An content= Ca/(Ca +Na+ K).
The GB geothermometer calibration of Perry and Spear (1978) is the original
experimentally-determined GB geothermometer method and includes no correction for
Ca or Mn in garnet and assumes no Fe3 +in biotite, resulting in± 50°C error.
Recalibration by Holdaway (2000) suggests the Fe3 + content is 11.6 % on average in natural reduced biotite and 3 % in natural garnet. The calculated temperature decreases by approximately 38.5° when Fe3 +is accounted for because only the Fe2+ exchanges with
Mg and is used in the calculation. The objective of this study is to obtain general estimates for temperature and pressure in order to deduce possible sample origins.
Therefore, an error of± 50°C does not change the general outcome of this study and is considered a geologically reasonable estimate, though most likely the calculated
51 2 temperatures are too high as a result of assuming that all iron is Fe +. All of the
following temperatures calculated in this study do not correct for the different valence
states of iron.
Calculated GB temperatures for ten samples, based on the Ferry and Spear (1978)
GB geothermometer, are determined by the following equation:
(1) lnK= -2109/T (°K) + 0.782,
where K = (Mg/Fe)gametl(Mg/Fe)biotite. Temperatures calculated from this equation
correlate well with temperatures obtained from GTB (GeoThermoBarometry) software
(Spear and Kohn, 2006) using the same calibration model. All geothermobarometry plots
presented here were generated from this software.
Pressures determined by GASP geobarometry rely on the breakdown of anorthite
to grossular, aluminum-silicate, and quartz. The following equations suggested by
Newton and Hasselton (1981), and calculated by GTB software, are as follows:
(2) P (kbar) = -2.1 + 0.0232 T (°C) with kyanite
P (kbar) = -0.6 + 0.0236 T (°C) with sillimanite
Experimental data estimate errors associated with the GASP geobarometer to be ±1.1 kbar (Newton and Hasselton, 1981).
Pressures and temperatures determined by GB and GASP geothermometry for
five aluminum-silicate gneisses show a wide range of conditions (Figures 16b,d,f, 17f,
and 19a). Sillimanite-bearing samples include AGD, AGF, MRJ, and MRH, while kyanite occurs in AGH and MRH. MRH is the only sample to contain both aluminum-
silicate polyrnorphs, with relict kyanite enclosed in sillimanite. All samples yield metamorphic conditions similar to those seen in schists and gneisses of the Nimrod
52 Group, with the exception of a very high core temperature in AGD and very high
pressures in AGH.
Sillimanite-cordierite-gamet-biotite gneiss (AGD) gives temperatures >900°C in
the garnet core 700°C at the garnet rim (Figure 16b). The garnet core pressure is
very high at > 14 kbar, while the rim 7 .5 kbar. The geothermobarometry results
from this sample are not consistent with the petrographic observations of sillimanite. The
geothermobarometry data suggest metamorphic conditions are within the kyanite stability
field. Uncertainties associated with both GB and GASP, however, allow that the P and T
of equilibrium do overlap the stability field for sillimanite. Cordierite composition, though not determined in this study, may be used to refine metamorphic conditions.
Upper pressure limits of cordierite stability across most Mg/Fe ratios range from 6-10 kbar (Deer et al., 1992) and in rock compositions with excess aluminosilicate and temperatures below 1000°C cordierite breaks down to garnet, sillimanite, and quartz.
Therefore, in the presence of cordierite it is likely that sample AGD equilibrated near the high-P region of sillimanite stability. Furthermore, the difference between core and rim compositions is consistent with garnet growth during cooling and decompression.
Sillimanite-muscovite-gamet-biotite gneiss (AGF) exhibits the lowest temperatures of and pressures just below 4 kbar (Figure 19a), consistent with the sillimanite stability field. Garnets in this sample are very small (<0.5 mm diameter), irregular in shape, and surrounded by green biotite. Analyses are whole-garnet compositions with no rim or core data and no garnet composition profiles were obtained.
Geothermobarometry results exhibit retrograde metamorphism within the sillimanite stability field for sillimanite-gamet-biotite gneiss (MRJ). Gamet core
53 temperatures and pressures are -830°C and -8.5 kbar, while garnet rim conditions are
-660°C and -5 kbar, indicating a late retrograde cooling and decompression.
GB and GASP geothermobarometers show metamorphic conditions in the
sillimanite stability field for kyanite-sillimanite-gamet-biotite gneiss (MRH).
Petrographic observation of sillimanite surrounding kyanite, combined with
geothermobarometry, suggest prograde metamorphic conditions transitioning from the kyanite zone to the sillimanite zone. Gamet core conditions are determined to 780°C
and-6 kbar, while garnet rim conditions are -610°C and-3 kbar.
Kyanite-gamet-biotite gneiss (AGH) exhibits high temperatures and very high pressures, consistent with the kyanite stability zone. Gamet core P-T conditions are
-800°C and -14.5 kbar, whereas garnet rim conditions are -790°C and -11 kbar, indicating nearly isothermal decompression.
Different metamorphic conditions are determined by GB geothermometry in two garnet-bearing gneisses. Gamet-biotite gneiss (AGE) shows a very small temperature change from core, -600°C, to rim, -590°C. The garnet composition map (Figure 15b) and the garnet profile (Figure 17a) show a distinct calcium increase in the core, not due to the presence of fractures which are evident in the backscatter image (Figure 15a).
Compositions used in the calculations were chosen from the area with the calcium increase because it comprises the majority of the crystal with a clear zonation from core to rim.
Gamet-biotite gneiss (AGG) shows the largest temperature decrease during retrograde conditions. Gamet core temperature is -800°C and the rim is -480°C (Figure
17d), although more erratic compositions in the outer domain relative to other samples
54 suggests the possibility of disequilibrium or that the particular rim compositions used are not representative.
Phyllites (TNE and TNF) show low-grade temperatures that are consistent with known metamorphic conditions (greenschist to hornblende-hornfels facies; Goodge,
1997) in the Beardmore Group. Staurolite-garnet-biotite-muscovite phyllite (TNE) is the only prograde sample in this suite ofphyllites and the equant garnet shows uniform element zoning (Figure 15d and 18e). GB temperatures are at the garnet core and at the garnet rim. Staurolite in this sample has XMg = 0.13 and is useful to refine metamorphic conditions. XMg values <0.3 indicate pressures > 1.5 kbar and temperatures of 500-700°C (Deer et al., 1992). This is consistent with the GB temperatures and constrains metamorphic pressures.
Garnets in tourmaline-andalusite-garnet-biotite-muscovite phyllite (TNF) are very small (<0.5 mm diameter), irregular in shape, and surrounded by biotite. Analyses are whole-garnet compositions with no rim or core data and no garnet composition profiles were obtained. A GB temperature of was determined for this sample at pressures lower than 3 kbar because of the presence of andalusite (Figure 19b ).
Temperatures for eclogite (MRT) were determined by the GB geothermometer and three GCPX geothermometers, including Ellis and Green (1979), Powell (1985b), and Pattison and Newton (1989). The GCPX geothermometers use the following relations:
(3) Ellis and Green, 1979: T(K) = 3104 XGt.ca + 3030 + 10.86 P 1n KD + 1.9034
55 (4) Powell, 1985b: T(K) = 3140 X Gt.Ca+ 2790 + 10 P lnKD + 1.735
where P is in kbar and X is the mole fraction of Ca in garnet
3 2 (5) Pattison and Newton, 1989: T(K) = a' X +b'X +c'X+d' +5.5(P-15) ln Kn+aoX3+boX2+coX +do
where P is in kbar and X is the Mg number in garnet.
Equation 4 is a recalibration of equation 3 and produces temperatures that are approximately 20° lower. The authors do not include a margin of error with these calculations, however Powell (1985a) notes that the minerals may continue to equilibrate upon cooling and therefore calculated temperatures may not reflect the high temperature event. Errors associated with equation 5 are stated to be ± 30°C, not including the analytical uncertainty of the measured compositions and solid solution in these natural minerals.
MRT garnets are generally large (- 1.5 mm radius) and fractured with many inclusions. A plagioclase-clinopyroxene symplectite surrounds most garnet edges
(Figure 15e,f). Composition profiles show uniform zoning in the small garnet and irregularity in the large garnet (Figures 15g and 17a,c). Because of this, the small garnet
2 composition is used in all calculations, assuming all Fe is Fe +.
GTB software was used to calculate retrograde changes based on four geothermometers. GB and Pattison and Newton (1989) show similar core temperatures
(Figure 18b,d) of -660°C and 680°C, while the calibrations of Ellis and Green (1979) and
Powell (1985) yielded core temperatures of-770°C and 750°C, respectively. Rim temperatures are around 500°C (Ferry and Spear, 1978; Pattison and Newton, 1989) and
56 600°C (Ellis and Green, 1979; Powell, 1985). Retrograde cooling is consistent with petrographic evidence of symplectite globularization, indicating pressure reduction
(Joanny, 1991). MRT is likely to come from the Nimrod Group, where large mafic blocks contain cores of fine-grained, partially preserved eclogitic mineral assemblages
(Goodge, et al., 1992; Peacock and Goodge, 1995).
Two GH geothermometers, Graham and Powell (1984) and Perchuk et al. (1985), are utilized in this study on amphibolite (KTF). These geothermometers use the following relations:
(6) Graham and Powell, 1984: T(K) = 3280 Xat.ca + 2880 lnKD + 2.426
(7) Perchuk, et al., 1985: T(K) = 3330 lnKD + 2.333
Graham and Powell's (1984) GH geothermometer is useful in Mn-poor garnets that experienced temperatures less than 850°C. They note that, "application to 'eclogitic' garnet amphibolites suggests garnet and hornblende seldom attain Fe-Mg exchange equilibrium in these rocks." Perchuck et al. (1985) suggest temperatures above 550°C are ideal for Fe-Mg exchange. Errors associated with these geothermometers are not clearly stated.
Garnets in KTF are sparse, very small (<0.5 mm diameter), and are irregular in shape. For these reasons, analyses are whole-garnet compositions with no rim or core data and no profiles. GTB software calculated very high GH temperatures of - 1055°C
(Graham and Powell (1984) and-920°C (Perchuk, et al., 1985). KTF is likely from the
Nimrod Group, where amphibolitic rinds are found surrounding mafic blocks and relict
57 eclogite (Goodge, et al., 1992). This eclogitic association suggests Fe-Mg equilibrium was not attained, as stated above; therefore, the determined temperatures are probably not geologically meaningful.
Geothermobarometry on these 11 samples shows a wide range of conditions, clearly showing different rock type origins. Most correlate with conditions from known outcrops, while some remain unique with uncertian origins. P-T conditions from exposed rocks and the moraine samples in this study are summarized in Figure 20 and Table 1, with the exception ofKTF.
20 central Transantarctic Mountains KEY Reactivated basement 18 NG Nimrod Group U-Pb ages (Ma) '-' Ml '\.eclogitei Metasedimentary assemblage igneous zircon 16 ' e BB Byrd and Beardmore groups \ metam. zircon 14 • metam. monazite 40Ar/39Ar ages (Ma) • 12 EJ hornblende muscovite 10 B• Inferred age (Ma) 8 --- - -, ace retlonary belts
_,.---, basement paths 6
.,.- collisional assemblages
...... - -) HP and UHP rocks 4
...... - plutonic/migmatitic and ' contact assemblages 2 - - estimated P. calculated T calculated P-T 300 400 500 600 700 800 Temperature (°C) Figure 20. P-T summary plot of known rocks in the central TAM and moraine rocks from this study (colored lines). Moraine samples with dashed lines are calculated temperatures and estimated pressures, while moraine samples with soild lines are calculated temperatures and pressures. Modified from Goodge, 2007. 58 T (°C) T (°C) P {kbar} P {kbar} garnet core garnet rim garnet core garnet rim AGO >900 -700 >14 -7.5 AGE -600 -590 AGF -550 <4 AGG -800 -480 AGH -800 -790 -14.5 -11 MRH -780 -610 -6 -3 MRJ -830 -660 -8.5 -5 MRT -660 -680 TNE -400 -500 TNF -550 <3
Table 1. Geothermobarometry results for collected moraine samples. Data from GB, GASP, and GH geothermobarometers.
In general, the moraine samples show retrogression patterns similar to rocks found in the
Nimrod Group and the Beardmore Group. In particular, several gneissic rocks have zoned garnets that yield cooling and decompression paths that are similar to changes inferred from Nimrod Group gneisses. Other samples (TNE) show low-T prograde heating paths similar to those inferred for Beardmore Group rocks near granitic plutons.
Yet other samples (MRT and AGH) show decompression paths with a near-isothermal trajectory that is similar to that inferred from Paleoproterozoic eclogitic relics in the
Nimrod Group (Goodge et al., 2001); of particular interest is sample AGH, which is a high-P gneiss not previously known from the Nimrod Group and may be exotic.
Magnetic Susceptibility
Magnetic susceptibility data provide another tool to compare collected rock samples with measured magnetic susceptibilities of outcrops in the TAM and aeromagnetic data of the sub-ice rock types. Arrangement of rock types by magnetic susceptibility yields several similarities, as shown in Figure 21. Samples are sorted with magnetic susceptibility decreasing downward. The majority of metamorphic, igneous, 59 Rock Type & Magnetic Susceptibility
Gneiss I Amphibolite 11 Quartzite 11 Marble II Eclogite I KTF 2.1 TNN 0 KTT 0 MRT 0.1 Grt-bt±ms , , --···- , Other Other MRZ 1.7 KTP 0 MRO 0.05 KTV 1.8 KTAH 0.03 MRAA 0.04 KTQ 0 KTN 0.05 AGN 0.05 AGO 0.02 AGE 0.02 KTE 0.05 KTH 0.02 AGG 0.02 AGS 0.02 TNPO AGH 0.02 AGJ 0.02 Metamorphic MRG 0.02 AGI 0.01 MRAB 0.01 MRAC 0.01 KTL 0.01 KTM 0.01 KTO 0.01 MRWO MRXO KTU 0
I Granodiorite 11 Leucodiorite 11 Monzodiorite monzodiorife] !Dolerite· 1 MRU 0.01 KTAA 0 KTAB 0 KTAE 0.45 MRN 1.1 Ms-bt AGM 1.0 TNQ 0.27 MRF 0.83 Tour-ms-bl TNL 0.15 -, I AGL0.45 TNKO AGKO ··-- - -- MRM 0.43 Igneous TNRO MRE O MRK 0.34 TNSO TNGO TNH 0.11 KTACO TNJ 0 KTJ 0 KTWO KTZO KTAFO
I Sandstone I r Diamictite I Sedimentary KTD 0.01 TND 0 TNIO
Fiaure 21 . Rock tvoes collected at orimarv site locations arranaed b 0\ 0 and sedimentary rock types have susceptibilities <0.1 x 10-3 cgs. Metamorphic rocks generally show higher susceptibility values, although some higher values are seen in igneous rocks.
Metamorphic and igneous rock types that contain amphibole show the largest susceptibilities, with the greatest value of 3.2 x 10-3 cgs from hornblende-biotite gneiss
(KTY). Other high values include 2.1 x 10-3 cgs from biotite-hornblende gneiss (MRQ) and garnet amphibolite (KTF). These high values are comparable with susceptibilities measured in the Miller and Geologist ranges (J.W. Goodge, unpublished data), but do not correspond with the anomalously high susceptibilities measured under the EAIS near
Nimrod Glacier (Finn et al., 2006; Anderson et al., 2006; Goodge et al., 2004c; Goodge et al., 2004d).
61 DISCUSSION
Sampling from eight moraine locations near Nimrod Glacier provided 156 large clasts that show evidence for both glacial transport and local rock fall. Selected rock types chosen on the basis of petrographic observations were analyzed for igneous whole- rock geochemistry (31 samples) and metamorphic mineral composition (11 samples).
Unique samples or those with similarities to other samples in the moraine suite are described below.
Based on geochemical data, the origin of many samples can be predicted for groups of rocks that show similarities to local outcrops. Petrography and geochemical data, with the exception of mobile element Rb, suggest samples TNK, TNS, TNR,
KTAC, TNG, and AGT are from the Granite Harbour Intrusive series. High Rb values in most of these samples contrast with values in the Granite Harbour rocks; however, with altered feldspars in all samples, the high Rb may be caused by hydrothermal alteration.
Other samples likely related to the Granite Harbour suite are MRP, MRU, KTJ,
KTZ, and KT AF, and probably AGK, MRD, and MRE. MRP shows an extremely high
Sr content, possibly as a result of element mobility and the sample's well-developed deformation fabric. AGK, MRD, and MRE are similar and show some elevated trace element values. Element mobility may cause trace element differences, such that these samples may also be derived from the Granite Harbour Intrusives.
Ten samples are likely to originate from a source other than the Granite Harbour suite. These samples show unique characteristics in both petrography and geochemistry when compared with published Granite Harbour data. When compared to other samples in the collected moraine suite, some samples show similarities, while a few are different.
62 For example, MRY and MRQ are similar to each other in mineralogy, deformation fabric, geochemistry, and magnetic susceptibility. Samples KTK and KTAE show similar trace element patterns and magnitudes when compared with patterns obtained from MRY and MRQ (Figure 12c). In general, these four samples lie above published data in the Harker diagrams (Figures 9 and 10) and all contain large poikilitic feldspar, but they show distinct differences in overall appearance when compared to each other. Perhaps the whole-rock samples for these rocks contained a large feldspar concentration, resulting in very similar geochemical data. Alternatively, these rocks may be related as a group or from the same parent magma. As a whole, these samples are unique from the known granitoid data and may represent rocks derived from under the ice sheet.
A few samples are unique petrographically and geochemically from published data and the remainder of the collected moraine suite. These samples include KTAA,
KTAB, AGJ, TNQ, KTW, and KTAD. The low silica contents in KTAA and KTAB are unusual for the Granite Harbour suite and these samples rarely plot within the published data (Figures 9 and 10). Samples AGJ, TNQ, KTW, and KTAD show high values in immobile elements Y, Cr, and Zr. Petrographically these samples are also unique when compared with other moraine samples: AGJ is a light-gray garnet-bearing gneiss, while
TNQ, KTW, and KTAD are distinctive shades of pink and show deformation fabrics.
Geothermobarometry documents low-grade P-T conditions in a few rocks and high P-T conditions in several others. The low-grade samples were metamorphosed under similar conditions as the Beardmore Group, while the high-grade samples are
63 similar to the Nimrod Group (Figure 20). A few samples experienced exceptionally high temperatures (AGD and MRJ).
Phyllites (TNE and TNF) are likely to be part of the Beardmore Group, while the remaining 9 metamorphic samples show similarities to the Nimrod Group. P-T conditions of cooling and decompression are recorded in gneisses (AGD, AGE, AGF,
AGG, AGH, MRH, and MRJ), eclogite (MRT), and amphibolite (KTF), similar to the P-
T paths suggested for Ross Orogen metamorphism of the Nimrod Group (Goodge, 2007).
AGH and AGD show very-high metamorphic conditions not observed in gneisses of the
Miller and Geologist ranges.
MRT metamorphic conditions are consistent with eclogitic rocks in the Nimrod
Group. Nimrod Group eclogites seen in the central TAM are enclosed by large mafic blocks (Grindley and Laird, 1969; Goodge et al., 1992). These eclogites contain pyrope- rich relict garnet with XMg = 0.47 (Goodge et al., 1992), similar to MRT garnet of XMg =
0.57. Symplectite assemblages are found surrounding garnets that experienced P = 12-25 kbar and T = 600°C (Goodge et al., 1992). MRT garnets are surrounded by plagioclase and clinopyroxene symplectites and calculated temperatures extend through 600°C from core to rim (GB and CPX geothermometers). Physical characteristics of the MRT clast
(well-rounded edges, rod-shape, and glacial striations) suggest glacial transport and evidence for eclogitic blocks under the EAIS. The location of these sub-ice eclogites is unknown.
Sillimanite quartzite (KTQ) is unique because of its high temperature mineral assemblage in a quartzite composition. Observed quartzites in the TAM do not contain
64 sillimanite, however they are found in other Antarctic locations such as the Napier
Complex in Enderby Land, East Antarctica (Motoyoshi, 1998).
The majority of collected moraine samples at primary site locations show some
evidence for glacial transport such as rounded edges. Glacially transported rocks collected from sites nearest the Polar Plateau (Argo Glacier, Milan Ridge, and Turret
Nunatak) are likely to be derived from somewhere under the EAIS. The lack of sub-
aerial sources upstream of these moraines, and the presence ofrounded edges, eliminates the possibility of a local rock fall origin. The extent of glacial transport is unknown but is restricted to the catchment area of Nimrod Glacier (Figure 4).
Sub-ice geology and topography can be inferred from magnetic and gravity data
(Figure 5; Studinger et al., 2004; Finn et al, 2006; Anderson et al., 2006, Goodge et al.,
2004c; Goodge et al., 2004d). Although the sub-ice profile shown is km north of the study area, the general morphology of the profile is likely to extend to the Nimrod
Glacier region. Plateau areas in the TAM, as suggested by Studinger et al. (2004), are interpreted to be Ferrar Group overlying Beacon Supergroup. Aeromagnetic data near
Nimrod Glacier show a Ross Oro gen trend which extends -100 km from the exposed rock units underneath the ice sheet. This trend is followed by very high magnetic anomalies (Finn et al, 2006; Anderson et al., 2006, Goodge et al., 2004c; Goodge et al.,
2004d). Although magnetic susceptibilities from collected moraine samples are not high enough to explain the sub-ice magnetic anomalies, they are consistent with values seen in the Miller and Geologists ranges (J.W. Goodge, unpublished data). Either the collected moraine samples have only traveled on order of 100 kilometers in distance or the collected suite simply contains none of these highly-magnetic samples. There is no
65 evidence to rule out either possibility and based on the small number of randomly collected rocks it is more likely that high-magnetic samples are present in the moraines and were just not found.
Additional questions of the sub-ice geology are raised in the controversial reconstructions of supercontinent Rodinia. The paleogeographic position of East
Antarctica differs among the several Rodinia reconstructions discussed earlier. Goodge and Vervoort (2006) suggest that Laurentian 1.4 Ga A-type granites are centrally located within Rodinia. If these granitic rocks are located under the EAIS, perhaps the natural glaciation process of entrainment, transport, and deposition will provide the opportunity to sample these hidden rock types and provide further connections between East
Antarctica and Laurentia. At this time, a few samples may show A-type characteristics, but A-type rocks are also seen in the Granite Harbour series (Allibone et al., 1993). Until geochronology can be completed on these samples, a connection between these two continents can not be determined by this study.
66 CONCLUSIONS
Petrography, igneous whole-rock geochemistry, metamorphic mineral composition, and magnetic susceptibility are used to describe 156 large rock clasts collected from glacial moraines near Nimrod Glacier, East Antarctica. Sample data are compared with known outcrops in order to identify possible origins for the moraine clasts and predict sub-ice contributions from the East Antarctic shield.
Igneous whole-rock geochemistry and geothermobarometry identify many samples derived from known and exposed rock types. A few show unexplained anomalies such as elevated immobile trace element concentrations, when compared to published Granite Harbour suite data or other samples within the moraine suite, or very high-grade metamorphism. Extreme P-T conditions seen in a few samples are not consistent with exposed rock types. Perhaps these rock types only exist in a sub-ice setting, where the glaciers have eroded deep into the TAM.
Most of the moraine suite is likely to originate from a nearby exposed source in the central TAM. This larger group thus indicates that much of the glacial debris captured at the head of a major outlet glacier, such as Nimrod Glacier, may have a provenance within the broadly define Ross Oro gen. Few samples unique in petrography, geochemistry, and/or P-T conditions may be from a source unseen in the Nimrod Glacier region. These rocks have the greatest potential for providing information on the lithologic character of the sub-ice region and, even if in lower abundance, may yield important insight into the character and age of the adjacent East Antarctic shield. They therefore represent the best targets for future geochronology.
67 Base on the results of this study, 20 rocks were selected for geochronology, which will provide information to aid in refining sample history and origin, perhaps leading to further correlations in the Rodinia supercontinent assemblage.
Additional questions remain because of limited information about the glacial flow characteristics of Nimrod Glacier. Ultimately, it is unclear how far samples were carried and their origin. Further investigation on glacial processes in the Nimrod Glacier region can place restrictions on the origin of clasts used in this study.
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76 Appendix A Sample Descriptions
Argo Glacier AGD Sillimanite-cordierite-garnet-biotite gneiss is a white and black medium-grained (1-5 mm) rock with compositional banding and crystalloblastic garnet (1-2 mm). Microtextures consist of anhedral grain shape, mynnekite, anti-perthite, feldspar alteration and zoning, tapered plagioclase twins, undulose extinction in quartz, and equant poikiloblastic garnet. The gneiss contains quartz, plagioclase feldspar, garnet, biotite, muscovite, cordierite, and sillimanite, with accessory sericite, chlorite, apatite, sphene, zircon, and opaque. An unknown yellow isotropic mineral surrounds most of the cordierite. Appendix C lists electron microprobe mineral composition data.
AGE Garnet-biotite gneiss is a white and black medium-grained (1-5 mm) rock with compositional banding, foliation, mineral-alignment lineation, and crystalloblastic garnet (1-4 mm). Microtextures consist of anhedral grain shape that defines wavy sub grain shape preferred orientation (SSPO) and weak lattice preferred orientation (LPO), anti-perthite, feldspar zoning, tapered plagioclase twins, undulose extinction in quartz, and equant poikiloblastic garnet. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, and biotite, with accessory apatite, zircon, and opaque. Appendix C lists electron microprobe mineral composition data.
AGF Sillimanite-muscovite-garnet-biotite gneiss is a dark medium-grained (1-2 mm) rock with compositional banding, foliation, and mineral-alignment lineation. Microtextures consist of anhedral grain shape that defines weak LPO of larger quartz grains, mynnekite, tapered plagioclase twins, and undulose extinction in quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, biotite, muscovite, and sillimanite, with accessory zircon and opaque. Appendix C lists electron microprobe mineral composition data.
77 AGG Garnet-biotite gneiss is a grey fine-grained(< 1 mm) rock with compositional banding, foliation, and crystalloblastic garnet ( 1 mm). Microtextures consist of anhedral grain shape that defines undulose extinction in quartz, feldspar zoning, tapered plagioclase twins, and equant poikiloblastic garnet. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, biotite, and muscovite, with accessory apatite, zircon, and opaque. Appendix C lists electron microprobe mineral composition data.
AGH Kyanite-garnet-biotite gneiss is a dark medium-grained (1-5 mm) rock with compositional banding, foliation, mineral-alignment lineation, and crystalloblastic garnet (1-5 mm). Microtextures consist of anhedral grain shape that defines planar SSPO, anti-perthite, undulose extinction in quartz, feldspar zoning, tapered plagioclase twins, and equant poikiloblastic garnet. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, kyanite, and biotite, with accessory apatite, zircon, and opaque.
AGI Garnet-biotite gneiss is a dark medium-grained (1-5 mm) rock with compositional banding, foliation, mineral-alignment lineation, and crystalloblastic garnet ( 1 mm). Microtextures consist of anhedral grain shape that defines wavy grain-shape preferred orientation (GSPO) and LPO, myrmekite, anti-perthite, feldspar alteration and zoning, undulose extinction in quartz, and equant poikiloblastic garnet. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, and biotite, with accessory sericite, apatite, zircon, and opaque.
AGJ Sillimanite-muscovite-garnet-biotite gneiss is a light grey medium-grained (1-5 mm) rock with weak foliation, weak mineral-alignment lineation, and crystalloblastic garnet (2-10 mm). Microtextures consist of subhedral grain shape, myrmekite, feldspar alteration and zoning, undulose extinction in quartz, radial and/or bent biotite, and pseudomorphs of equant garnet replaced by biotite, plagioclase feldspar, potassium feldspar, and quartz. The gneiss contains
78 quartz, plagioclase feldspar, potassium feldspar, garnet, biotite, muscovite, and sillimanite, with accessory sericite, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
AGK Muscovite-biotite granite is a light grey medium-grained (1-5 mm) rock with weak foliation and mineral-alignment lineation. Microtextures consist of anhedral grain shape that defines wavy GSPO and weak LPO, myrmekite, feldspar alteration and zoning, chlorite replacement of biotite, ribbon quartz, and undulose extinction in quartz. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory sericite, chlorite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
AGL Dolerite is a dark medium-grained (1-5 mm) rock. Microtextures consist of subhedral grain shape, plagioclase feldspar zoning, lath-shaped plagioclase feldspar, and subophitic growth of pyroxene and plagioclase. The dolerite contains plagioclase feldspar and pyroxene, with accessory opaque. Appendix B lists the whole rock geochemical data.
AGM Dolerite is a dark fine-grained(< 1 mm) rock. Microtextures consist of subhedral grain shape, lath-shaped plagioclase feldspar, very fine-grained matrix, plagioclase feldspar zoning, and subophitic growth of pyroxene and plagioclase. The dolerite contains plagioclase feldspar and pyroxene, with accessory opaque. Appendix B lists the whole rock geochemical data.
AGN Biotite-pyroxene gneiss is a black fine to medium-grained ( < 1-5 mm) rock with weak compositional banding, foliation, and mineral-alignment lineation. Microtextures consist of anhedral grain shape, rounded quartz grains, undulose extinction in quartz, recrystallized quartz, and plagioclase feldspar kink bands, tapered twins, and curved twins. The gneiss contains detrital quartz, plagioclase feldspar, biotite, and pyroxene, with accessory apatite, zircon, and opaque.
79 AGO Garnet-biotite schist is a black fine to medium-grained(< 1-3 mm) rock with foliation, mineral-alignment lineation, and crystalloblastic garnet(< 1 mm). Microtextures consist of anhedral grain shape that defines wavy SSPO and LPO, feldspar alteration and zoning, tapered plagioclase twins, undulose extinction in quartz, and ribbon quartz. The schist contains quartz, plagioclase feldspar, potassium feldspar, garnet, and biotite, with accessory sericite, apatite, zircon, and opaque.
AGP Sillimanite-garnet-biotite-muscovite schist is a dark grey medium-grained (1-5 mm) rock with foliation and elongation lineation. Microtextures consist of anhedral grain shape that defines wavy SSPO and LPO, feldspar alteration, undulose extinction in quartz, ribbon quartz, and tapered plagioclase twins. The schist contains quartz, plagioclase feldspar, garnet, biotite, muscovite, and sillimanite, with accessory apatite, zircon, and opaque.
AGQ Biotite-hornblende gneiss is a black fine to medium-grained ( < 1-5 mm) rock with compositional banding, foliation, and elongation lineation. Microtextures consist of anhedral grain shape that defines wavy GSPO and LPO, feldspar alteration and zoning, tapered plagioclase twins, undulose extinction in quartz, ribbon quartz, and poikilitic hornblende. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, biotite, and hornblende, with accessory sericite, apatite, zircon, and opaque.
AGR Kyanite-sillimanite-garnet-biotite gneiss is a dark medium-grained (1-5 mm) rock with compositional banding, foliation, and mineral-alignment lineation. Microtextures consist of anhedral grain shape, anti-perthite, feldspar zoning, tapered plagioclase twins, and undulose extinction in quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, biotite, kyanite, and sillimanite, with accessory zircon and opaque.
AGS Garnet-pyroxene-hornblende-biotite gneiss is a green medium to coarse-grained (1-10 mm) rock with compositional banding, foliation, and crystalloblastic 80 garnet (1 mm). Microtextures consist of anhedral grain shape that defines weak LPO, feldspar alteration and zoning, tapered plagioclase twins, undulose extinction in quartz, and recrystallized quartz veins. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, biotite, hornblende, and pyroxene, with accessory sericite, sphene, zircon, and opaque.
AGT Garnet-muscovite pegmatite is a white medium-grained (1-5 mm) rock with muscovite porphyry (5-10 mm). Microtextures consist of anhedral grain shape including feldspar alteration and zoning, grey-green color replacement in muscovite, undulose extinction in quartz, and poikilitic muscovite and feldspar. Equant crystalloblastic garnet(< 1 mm) is abundant and concentrated in a small area. The pegmatite contains quartz, plagioclase feldspar, potassium feldspar, and muscovite, with accessory sericite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
Milan Ridge MRD Hornblende-biotite granite is a pink medium-grained (1-5 mm) rock with weak foliation and mineral-alignment lineation. Microtextures consist of anhedral grain shape that defines wavy GSPO and LPO, myrmekite, feldspar alteration and zoning, chlorite replacement of biotite, undulose extinction in quartz, ribbon quartz, and recrystallized quartz. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and hornblende, with accessory sericite, chlorite, epidote, sphene, zircon, and opaque. Appendix B lists the whole rock geochemical data.
MRE Muscovite-biotite granite is a white medium-grained (1-5 mm) rock with foliation and mineral-alignment lineation. Microtextures consist of anhedral grain shape that defines weak LPO, feldspar alteration and zoning, undulose extinction in quartz, recrystallized quartz, ribbon quartz, and poikilitic feldspar. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and
81 muscovite, with accessory sericite, chlorite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
MRF Dolerite is a dark grey medium-grained (1-5 mm) rock. Microtextures consist of anhedral grain shape, plagioclase feldspar zoning, undulose extinction in quartz, lath-shaped plagioclase feldspar and pyroxene, and fine-grained matrix. The dolerite contains plagioclase feldspar and pyroxene, with accessory opaque. Appendix B lists the whole rock geochemical data.
MRG Garnet-biotite gneiss is a black and white medium-grained (1-5 mm) rock with compositional banding, foliation, mineral-alignment lineation, and crystalloblastic garnet (-1 mm). Microtextures consist of anhedral grain shape that defines wavy SSPO, myrmekite, perthite, anti-perthite, feldspar zoning, and undulose extinction in quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, biotite, and muscovite, with accessory apatite, zircon, and opaque.
MRH Kyanite-sillimanite-garnet-biotite gneiss is a light medium-grained (1-5 mm) rock with compositional banding, foliation, and crystalloblastic garnet (1-8 mm). Microtextures consist of anhedral grain shape that defines planar SSPO, anti- perthite, undulose extinction in quartz, feldspar alteration and zoning, tapered and bent plagioclase feldspar twins, equant poikiloblastic garnet, and sillimanite surrounding relict kyanite. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, biotite, muscovite, sillimanite, and kyanite, with accessory sericite, zircon, and opaque. Appendix C lists electron microprobe mineral composition data.
MRI Hornblende-biotite gneiss is a pink and black medium-grained (1-5 mm) rock with compositional banding, foliation, elongation lineation, and crystalloblastic hornblende (-2 mm). Microtextures consist of subhedral grain shape that defines wavy SSPO and LPO, feldspar alteration and zoning, ribbon undulose
82 extinction in quartz, and ribbon quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, biotite, and hornblende, with accessory sericite, zircon and opaque.
MRJ Sillimanite-garnet-biotite gneiss is a light medium-grained (1-5 mm) rock with weak compositional banding, foliation, and crystalloblastic garnet (1-5 mm). Microtextures consist of anhedral grain shape, undulose extinction in quartz, plagioclase kink bands, anti-perthite, and equant poikiloblastic garnet. The gneiss contains quartz, plagioclase feldspar, garnet, biotite, and sillimanite, with accessory zircon, and opaque. Appendix C lists electron microprobe mineral composition data.
MRK Dolerite is a dark green medium-grained (1-5 mm) rock. Microtextures consist of anhedral grain shape, plagioclase feldspar zoning, lath-shaped plagioclase feldspar, and subophitic growth of pyroxene and plagioclase. The dolerite contains plagioclase feldspar and pyroxene, with accessory opaque. Appendix B lists the whole rock geochemical data.
MRL Muscovite-biotite gneiss is a white and grey medium-grained (1-5 mm) rock with folding, compositional banding, foliation, and elongation lineation. Microtextures consist of anhedral grain shape that defines weak LPO, anti- perthite, feldspar alteration and zoning, tapered plagioclase twins, and undulose extinction in quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory sericite, apatite, zircon, and opaque.
MRM Dolerite is a grey fine-grained(< 1 mm) rock. Microtextures consist of subhedral grain shape, plagioclase feldspar zoning, lath-shaped plagioclase feldspar, very fine-grained matrix, and subophitic growth of pyroxene and plagioclase. The dolerite contains plagioclase feldspar and pyroxene, with accessory opaque. Appendix B lists the whole rock geochemical data.
83 MRN Dolerite is a grey medium-grained (1-5 mm) rock. Microtextures consist of subhedral grain shape, plagioclase feldspar zoning, lath-shaped plagioclase feldspar, very fine-grained matrix, feldspar alteration, and subophitic growth of pyroxene and plagioclase. The dolerite contains plagioclase feldspar and pyroxene, with accessory opaque. Appendix B lists the whole rock geochemical data.
MRO Garnet-muscovite-biotite gneiss is a light grey medium-grained (1-5 mm) rock with compositional banding, foliation, and crystalloblastic garnet (3-6 mm). Microtextures consist of anhedral grain shape, myrmekite, feldspar alteration and zoning, undulose extinction in quartz, and poikiloblastic garnet. Garnets show parallel sets of fractures and most are surrounded by very fine-grained matrix. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, biotite, and muscovite, with accessory sericite, apatite, zircon, and opaque.
MRP Muscovite-biotite gneiss is a pink and grey, fine to medium-grained ( < 1-5 mm) rock with foliation and elongation lineation. Microtextures consist of anhedral grain shape that defines planar SSPO and LPO, feldspar alteration and zoning, chlorite replacement of biotite, undulose extinction in quartz, ribbon quartz, recrystallized quartz, and poikilitic feldspar. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory sericite, chlorite, sphene, and zircon. Appendix B lists the whole rock geochemical data.
MRQ Biotite-hornblende gneiss is a pink coarse to very coarse-grained (5 - > 10 mm) rock with weak foliation and weak mineral-alignment lineation. Microtextures consist of anhedral grain shape that defines wavy SSPO and LPO, myrmekite, concentric rings of feldspar alteration and zoning, undulose extinction in quartz, ribbon quartz, recrystallized quartz, and equant poikilitic amphibole and feldspar. The gneiss contains quartz, plagioclase feldspar, potassium feldspar,
84 biotite, muscovite, and hornblende, with accessory sericite, sphene, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
MRR Hornblende-biotite gneiss is a pink and grey fine to medium-grained(< 1-5 mm) rock with compositional banding, foliation, and elongation lineation. Microtextures consist of anhedral grain shape that defines planar SSPO and LPO, flame-perthite, feldspar alteration and zoning, tapered plagioclase twins, ribbon quartz, recrystallized quartz, and undulose extinction in quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, biotite, and hornblende, with accessory sericite, sphene, apatite, zircon, and opaque.
MRS Sillimanite-garnet-biotite schist is a medium grey fine-grained(< 1 mm) rock with compositional banding, foliation, and elongation lineation. Microtextures consist of anhedral grain shape that defines wavy SSPO and LPO, perthite, feldspar alteration and zoning, undulose extinction in quartz, and ribbon quartz. The schist contains quartz, plagioclase feldspar, potassium feldspar, biotite, muscovite, and sillimanite, with accessory sericite, apatite, zircon, opaque, and possible spine!. Gamet was not found in thin section, but it is present in very small amounts in hand sample.
MRT Eclogite is a black fine-grained(< 1 mm) rock with foliation, lineation, and garnet porphyroblasts (1-5 mm). Microtextures consist of anhedral grain shape, foliation that wraps around garnet, and quartz veins. The garnet is equant, fractured, and poikiloblastic. Symplectites of plagioclase feldspar and clinopyroxene surround garnet. The eclogite contains quartz, plagioclase feldspar, garnet, biotite, pyroxene, and symplectite, with accessory zircon, and opaque. Appendix C lists electron microprobe mineral composition data.
MRU Garnet-muscovite-biotite granodiorite is a light grey medium-grained (1-5 mm) rock with foliation and mineral-alignment lineation. Microtextures consist of anhedral grain shape, myrmekite, perthite, feldspar alteration and zoning, recrystallized quartz, bent plagioclase feldspar twins, chlorite replacement of 85 biotite, and undulose extinction in quartz. The granodiorite contains quartz, plagioclase feldspar, potassium feldspar, garnet, and biotite, with accessory sericite, chlorite, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
MRV Biotite gneiss is a grayish pink medium-grained (1-5 mm) rock with folding, compositional banding, foliation, and weak mineral-alignment lineation. Microtextures consist of anhedral grain shape that defines wavy GSPO and LPO, feldspar alteration and zoning, tapered plagioclase twins, recrystallized quartz, quartz ribbons, and undulose extinction in quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory sericite, apatite, zircon, and opaque.
MRW Garnet-muscovite-biotite gneiss is a black and white fine to coarse-grained (< 1- 10 mm) rock with compositional banding, foliation, elongation lineation, and crystalloblastic feldspar (2-10 mm). Microtextures consist of anhedral grain shape that defines wavy SSPO and LPO, foliation that wraps around feldspar porphyroclasts, feldspar augen, feldspar alteration and zoning, bent and tapered plagioclase twins, undulose extinction in quartz, ribbon quartz, recrystallized quartz, and poikilitic feldspar. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, biotite, and muscovite, with accessory sericite, zircon, and opaque.
MRX Garnet-muscovite-biotite gneiss is a black and white fine to coarse-grained(< 1- 10 mm) rock with compositional banding, foliation, and weak mineral-alignment lineation. Microtextures consist of anhedral grain shape that defines wavy SSPO and LPO, foliation that wraps around feldspar porphyroclasts, feldspar augen, feldspar alteration and zoning, bent and tapered plagioclase twins, undulose extinction in quartz, ribbon quartz, recrystallized quartz, and poikilitic feldspar. The gneiss contains quartz, plagioclase feldspar, potassium feldspar,
86 garnet, biotite, and muscovite, with accessory sericite, apatite, zircon, and opaque.
MRY Biotite-hornblende gneiss is a pink and black coarse to very coarse-grained (5- > 10 mm) rock with weak foliation and weak mineral-alignment lineation. Microtextures consist of anhedral grain shape that defines wavy SSPO and LPO, concentric rings of feldspar alteration and zoning, chlorite replacement of biotite, undulose extinction in quartz, ribbon quartz, recrystallized quartz, and equant poikilitic hornblende and feldspar. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, biotite, and hornblende, with accessory sericite, chlorite, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
MRZ Epidote amphibolite is a dark fine-grained(< 1 mm) rock and a light medium- grained (1-5 mm) rock. The contact between the two rock types is at a high- angle to compositional banding, foliation, and elongation lineation. A quartz feldspar auge (10 mm) extends between the two rock types. Microtextures from the dark section include subhedral grain shape, wavy bands of variable quartz grain sizes, undulose extinction in quartz, ribbon quartz, feldspar alteration and zoning, tapered plagioclase twins, and poikiloblastic opaque. The amphibolite contains quartz, plagioclase feldspar, potassium feldspar, biotite, epidote, and amphibole, with accessory sericite, apatite, zircon, and opaque.
MRAA Garnet amphibolite is a very dark medium-grained (1-5 mm) rock with compositional banding, foliation, and elongation lineation. Microtextures consist of anhedral grain shape that defines wavy GSPO and LPO, feldspar alteration and zoning, tapered plagioclase twins, undulose extinction in quartz, ribbon quartz, and poikiloblastic amphibole. The amphibolite contains quartz, plagioclase feldspar, potassium feldspar, garnet, biotite, and hornblende, with accessory sericite, apatite, zircon, and opaque.
87 MRAB Garnet-biotite gneiss is a grey medium-grained (1-5 mm) rock with compositional banding, foliation, and crystalloblastic garnet (l-15mm). Microtextures consist of anhedral grain shape that defines wavy SSPO and LPO, mynnekite, flame-perthite, feldspar alteration and zoning, undulose extinction in quartz, and equant poikiloblastic garnet. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, and biotite, with accessory sericite, apatite, zircon, and opaque.
MRAC Muscovite-biotite gneiss is a dark grey medium-grained (1-5 mm) rock with compositional banding, foliation, and elongation lineation. Microtextures consist of anhedral grain shape that defines wavy SSPO and LPO, foliation that wraps around feldspar porphyroclasts, myrmekite, feldspar alteration and zoning, tapered plagioclase twins, undulose extinction in quartz, and ribbon quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory sericite, apatite, zircon, and opaque.
Turret Nunatak TND Diamictite is a green fine-grained ( < 1 mm) rock with angular elastic fragments (1-30 mm). Supported by fine-grained matrix are mostly uniform rounded quartz grains with few angular fragments of various sizes. Microtextures consist of anhedral grain shape, feldspar alteration and zoning, tapered plagioclase twins, and undulose extinction in quartz. The diamictite contains quartz, plagioclase feldspar, and potassium feldspar, with accessory garnet, sericite, chlorite, sphene, zircon, and opaque.
TNE Staurolite-garnet-biotite-muscovite phyllite is a dark silver fine-grained (< 1 mm) rock with folded laminations, foliation, elongation and mineral-alignment lineations, and porphyroblasts of garnet and biotite (1-5 mm). Microtextures consist of subhedral grain shape that defines planar SSPO and LPO of fine- grained muscovite, crenulation cleavage, recrystallized quartz, chlorite replacement of biotite, and equant poikiloblastic garnet, staurolite, and biotite
88 with relict wavy foliation. The phyllite contains quartz, garnet, biotite, muscovite, and staurolite, with accessory chlorite, zircon, and opaque. Appendix C lists electron microprobe mineral composition data.
TNF Tourmaline-andalusite-garnet-biotite-muscovite phyllite is a black and silver fine-grained(< 1 mm) rock with folded laminations, compositional banding, foliation, elongation lineation, and garnet and biotite porphyroblasts (1-2 mm). Microtextures consist of subhedral grain shape that defines wavy SSPO and LPO of fine-grained muscovite, crenulation cleavage, recrystallized quartz boundaries, and poikiloblastic garnet, andalusite, staurolite, and biotite. The phyllite contains quartz, garnet, biotite, muscovite, tourmaline, andalusite, and staurolite, with accessory apatite, zircon, and opaque. Appendix C lists electron microprobe mineral composition data.
TNG Muscovite-biotite granite is a tan coarse-grained (5-10 mm) rock. Microtextures consist of anhedral grain shape, feldspar alteration and zoning, prehnite replacement of biotite, undulose extinction in quartz, and poikilitic feldspar. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory sericite, prehnite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
TNH Dolerite is a dark fine to medium-grained ( < 1-2 mm) rock. Microtextures consist of euhedral grain shape, ophitic growth of pyroxene and plagioclase. The dolerite contains plagioclase feldspar, potassium feldspar, biotite, and pyroxene, with accessory sericite, chlorite, and opaque. Appendix B lists the whole rock geochemical data.
TNI Sandstone is a tan fine-grained (< 1 mm) rock. Microtextures consist of rounded grain shape, feldspar alteration and zoning, and undulose extinction in quartz grains. The sandstone contains detrital quartz, plagioclase feldspar, and potassium feldspar, with accessory garnet, sericite, and opaque.
89 TNJ Biotite-muscovite granite is a white medium-grained (1-5 mm) rock. Microtextures consist of subhedral grain shape, feldspar alteration and zoning, chlorite replacement ofbiotite, undulose extinction in quartz, and poikilitic feldspar. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory sericite, chlorite, apatite, zircon, and opaque.
TNK Tourmaline-biotite-muscovite granite is a white medium-grained (1-5 mm) rock. Microtextures consist of subhedral grain shape, feldspar alteration and zoning, chlorite replacement of biotite, undulose extinction in quartz, and poikilitic feldspar and muscovite. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, muscovite, and tourmaline with accessory sericite, chlorite, sphene, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
TNL Muscovite-biotite granite is a pink coarse-grained (5-10 mm) rock with foliation. Microtextures consist of anhedral grain shape, feldspar alteration and zoning, prehnite replacement ofbiotite, undulose extinction in quartz, recrystallized quartz, wavy zones of different quartz sizes, and poikilitic feldspar. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory prehnite, sericite, chlorite, sphene, apatite, zircon, and opaque.
TNM Biotite-muscovite phyllite is a dark grey fine-grained(< 1 mm) rock with foliation and elongation lineation. Microtextures consist of anhedral grain shape that defines planar SSPO and weak LPO, crenulation cleavage, feldspar alteration and zoning, recrystallized quartz, undulose extinction in quartz, and quartz veins. The phyllite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory sericite, zircon, and opaque.
90 TNN Muscovite-biotite phyllitic quartzite is a dark grey fine-grained (< 1 mm) rock with foliation and elongation lineation. Microtextures consist of rounded grain- shape, relict graded bedding, feldspar alteration, chlorite replacement of biotite, grain and matrix supported quartz, and recrystallized quartz. The quartzite contains quartz, feldspar, biotite, and muscovite, with accessory garnet, sericite, chlorite, apatite, zircon, and opaque.
TNO Staurolite-garnet-muscovite-biotite schist is a silver fine-grained ( < 1 mm) rock with compositional banding, foliation, elongation lineation, and garnet and biotite porphyroblasts (1-2 mm). Microtextures consist of subhedral grain shape that defines planar SSPO and LPO of fine-grained muscovite, crenulation cleavage, feldspar alteration and zoning, chlorite replacement ofbiotite, undulose extinction in quartz, recrystallized quartz, ribbon quartz, and poikiloblastic biotite. The schist contains quartz, potassium feldspar, garnet, biotite, muscovite, and staurolite, with accessory sericite, chlorite, sphene, apatite, zircon, and opaque.
TNP Tourmaline-biotite-muscovite schist is a shiny black fine to medium-grained (1- 5 mm) rock with foliation and elongation lineation. Microtextures consist of subhedral grain shape that defines planar SSPO and LPO of fine-grained muscovite, undulose extinction in quartz, recrystallized quartz, ribbon quartz, quartz vein, and poikiloblastic muscovite. The schist contains quartz, potassium feldspar, biotite, muscovite, and tourmaline, with accessory epidote, zircon, and opaque.
TNQ Muscovite-biotite granite is a pink very coarse-grained(> 10 mm) rock with foliation. Microtextures consist of subhedral grain shape that defines weak LPO, feldspar alteration and zoning, prehnite and chlorite replacement ofbiotite, undulose extinction in quartz, recrystallized quartz, and poikilitic feldspar. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and
91 muscovite, with accessory sericite, chlorite, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
TNR Tourmaline-biotite-muscovite granite is a white medium-grained (1-5 mm) rock. Microtextures consist of anhedral grain shape, feldspar alteration and zoning, chlorite replacement of biotite, undulose extinction in quartz, and poikilitic feldspar. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, muscovite, and tourmaline with accessory sericite, chlorite, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
TNS Tourmaline-biotite-muscovite granite is a white medium-grained (1-5 mm) rock. Microtextures consist of anhedral grain shape, feldspar alteration and zoning, chlorite replacement of biotite, undulose extinction in quartz, and poikilitic feldspar. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, muscovite, and tourmaline, with accessory chlorite, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
Kon-Tiki Nunatak KTD Biotite-muscovite meta-sandstone is a dark grey fine-grained(< 1 mm) rock with compositional banding. Microtextures consist of anhedral grain shape, rounded and recrystallized quartz, feldspar alteration and zoning, undulose extinction in quartz, and a calc-silicate vein. The meta-sandstone contains quartz, potassium feldspar, biotite, and muscovite; with accessory sericite, apatite, sphene, zircon, and opaque. The vein contains calcite, actinolite, diopside, and quartz.
KTE Chlorite-hornblende gneiss is a dark fine-grained ( < 1 mm) rock with compositional banding, foliation, and mineral-alignment lineation. Microtextures consist of subhedral grain shape, feldspar alteration and zoning and undulose extinction in quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, chlorite, and hornblende, with accessory sericite, apatite, zircon, and opaque.
92 KTF Garnet amphibo/ite is a dark medium-grained (1-5 mm) rock with crystalloblastic garnet (- 1 mm). Microtextures consist of subhedral grain shape, undulose extinction in quartz, feldspar alteration and zoning, tapered plagioclase twins, and poikiloblastic hornblende. The amphibolite contains quartz, plagioclase feldspar, garnet, and hornblende, with accessory chlorite and apatite. Appendix C lists electron microprobe mineral composition data.
KTG Muscovite-biotite spotted phyllite is a black fine-grained ( < 1 mm) rock with foliation, elongation lineation, and biotite porphyroblasts (2 mm). Microtextures consist of anhedral grain shape that defines planar SSPO and LPO of fine- grained muscovite, undulose extinction in quartz, quartz veins, and poikiloblastic biotite with relict foliation. The phyllite contains quartz, biotite, and muscovite, with accessory zircon, and opaque.
KTH Calcite-biotite schist is a dark grey and tan fine-grained(< 1 mm) rock with compositional banding, foliation, elongation lineation, and biotite porphyroblasts (-1 mm). Microtextures consist of subhedral grain shape, rounded quartz, recrystallized quartz, ribbon quartz, prehnite replacement of biotite, undulose extinction in quartz, and a calcite layer. It contains quartz, biotite, and pyroxene, with accessory prehnite, calcite, apatite, zircon, and opaque.
KTI Hornblende-biotite gneiss is a dark fine-grained ( < 1 mm) rock with compositional banding and potassium feldspar porphyroblasts (> 5 mm). Microtextures consist of subhedral grain shape that defines planar SSPO and weak LPO, feldspar alteration and zoning, tapered plagioclase twins, myrmekite, and undulose extinction in quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, green biotite, and hornblende, with accessory sericite, apatite, zircon, and opaque.
93 KTJ Biotite granite is a pink and grey coarse-grained (5-10 mm) rock with compositional banding, foliation, and mineral alignment lineation. Microtextures consist of anhedral grain shape, myrmekite, perthite, feldspar alteration and zoning, and undulose extinction in quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, biotite, and secondary muscovite, with accessory sericite, chlorite, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
KTK Hornblende-biotite granite is a pink medium-grained (1-5 mm) rock with weak foliation, weak mineral-alignment lineation, and feldspar porphyroblasts (10-20 mm). Microtextures consist of subhedral grain shape, myrmekite, alteration of feldspar and zoning, chlorite replacement ofbiotite, undulose extinction in quartz, ribbon quartz, and poikilitic feldspar. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and hornblende, with accessory sericite, chlorite, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
KTL Garnet-biotite gneiss is a dark medium-grained (1-5 mm) rock with weak foliation and garnet porphyroblasts ( mm). Microtextures consist of subhedral grain shape, myrmekite, feldspar alteration and zoning, tapered plagioclase twins, undulose extinction in quartz and equant poikiloblastic garnet. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, and biotite, with accessory sericite, apatite, zircon, and opaque.
KTM Muscovite-garnet-biotite gneiss is a light grey fine-grained ( < 1 mm) rock with weak foliation, weak mineral-alignment lineation, and garnet porphyroblasts (1- 5 mm). Microtextures consist of anhedral grain shape that defines weak LPO, feldspar alteration and zoning, undulose extinction in quartz, ribbon quartz, and equant poikiloblastic garnet. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, biotite, and muscovite, with accessory sericite, zircon, and opaque.
94 KTN Muscovite-garnet-biotite gneiss is a light grey medium-grained (1-5 mm) rock with weak compositional banding, weak foliation, and crystalloblastic garnet (1- 5 mm). Microtextures consist of anhedral grain shape that defines weak LPO, feldspar alteration and zoning, interlobate recrystallized quartz, undulose extinction in quartz, and equant poikiloblastic garnet. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, biotite, and muscovite, with accessory sericite, apatite, zircon, and opaque.
KTO Muscovite-garnet-biotite gneiss is a grey fine-grained ( < 1 mm) rock with weak foliation, weak mineral-alignment lineation, and garnet porphyroblasts (1-6 mm). Microtextures consist of anhedral grain shape, feldspar alteration and zoning, undulose extinction in quartz, ribbon quartz, and equant poikiloblastic garnet. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, and biotite, with accessory sericite, apatite, zircon, and opaque.
KTP Muscovite quartzite is a white fine-grained ( < 1 mm) rock with foliation and mineral-alignment lineation. Microtextures consist of anhedral grain shape that defines planar SSPO and LPO, feldspar alteration and zoning, undulose extinction in quartz, recrystallized quartz, and pinning microstructure. The quartzite contains quartz, potassium feldspar, and muscovite, with accessory sericite, zircon, and opaque.
KTQ Sillimanite-muscovite-biotite quartzite is a purple fine to medium-grained(< 1-5 mm) rock with grain size variation in hand sample. Microtextures consist of anhedral grain shape that defines weak LPO including undulose extinction in quartz, pinning microstructure, recrystallized quartz, and poikiloblastic quartz. The quartzite contains quartz, biotite, muscovite, sillimanite, and tourmaline, with accessory zircon and opaque.
KTR Tourmaline-sillimanite-biotite-muscovite schist is a silver fine-grained(< 1 mm) rock with foliation and elongation lineation. Microtextures consist of subhedral
95 grain shape that defines wavy SSPO and LPO of fine-grained muscovite, feldspar alteration and zoning, undulose extinction in quartz, recrystallized quartz, and ribbon quartz. The schist contains quartz, plagioclase feldspar, biotite, muscovite, sillimanite, and tourmaline, with accessory sericite, apatite, zircon, and opaque.
KTS Biotite gneiss is a grey fine-grained(< 1 mm) rock with compositional banding, foliation, elongation lineation, and feldspar porphyroblasts (2-5 mm). Microtextures consist of anhedral grain shape that defines planar SSPO and LPO, feldspar alteration and zoning, chlorite replacement of biotite, quartz ribbons, and undulose extinction in quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory sericite, chlorite, apatite, and opaque.
KTT Talc-amphibole marble is a white and grey fine-grained ( < 1 mm) rock with compositional banding, foliation, and mineral-alignment lineation. Microtextures consist of subhedral grain shape, equant calcite, fibrous bent talc, and compositional calcite/talc layering. The marble contains calcite and talc, with accessory amphibole, apatite, opaque, and possible corundum.
KTU Garnet-muscovite-biotite gneiss is a grey fine-grained(< 1 mm) rock with compositional banding, foliation, elongation lineation, and feldspar porphyroblasts (2-10 mm). Microtextures consist of subhedral grain shape that defines wavy SSPO and LPO, myrmekite, foliation that wraps around feldspar porphyroclasts, feldspar augen, feldspar alteration and zoning, chlorite replacement ofbiotite, quartz ribbons, and undulose extinction in quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, biotite, and muscovite, with accessory sericite, chlorite, apatite, and zircon.
KTV Garnet-muscovite-hornblende-biotite gneiss is a grey medium-grained (1-5 mm) rock with compositional banding, foliation, mineral-alignment lineation, and crystalloblastic feldspar (2-5 mm). Microtextures consist of anhedral grain 96 shape that defines planar SSPO and LPO, feldspar alteration and zoning, biotite replacement of chlorite, ribbon quartz, and undulose extinction in quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, garnet, biotite, muscovite, and hornblende, with accessory sericite, chlorite, apatite, zircon, and opaque.
KTW Muscovite-biotite granite is an orange-red medium to coarse-grained (1-10 mm) rock with weak compositional banding and foliation. Microtextures consist of anhedral grain shape that defines wavy SSPO, perthite, feldspar alteration and zoning, chlorite replacement ofbiotite, recrystallized quartz, and undulose extinction in quartz. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory chlorite, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
KTX Biotite-muscovite gneiss is a pink fine-grained(< 1 mm) rock with compositional banding, foliation, mineral-alignment lineation, and microcline porphyroblasts mm). Microtextures consist of anhedral grain shape that defines weak LPO, feldspar alteration and zoning, ribbon quartz, and undulose extinction in quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory sericite, chlorite, apatite, zircon, and opaque.
KTY Hornblende-biotite gneiss is a peach and grey fine-grained ( < 1 mm) rock with compositional banding, foliation, and mineral-alignment lineation. Microtextures consist of anhedral grain shape that defines LPO, feldspar alteration and zoning, tapered plagioclase twins, quartz ribbons, and undulose extinction in quartz. The gneiss contains quartz, plagioclase feldspar, potassium feldspar, biotite, muscovite, and hornblende, with accessory sericite, chlorite, apatite, sphene, zircon, and opaque.
KTZ Muscovite-biotite granite is a light grey coarse-grained (> 10 mm) rock with crystalloblastic potassium feldspar (10-25 mm). Microtextures consist of 97 anhedral grain shape, myrmekite, feldspar alteration and zoning, chlorite replacement ofbiotite, undulose extinction in quartz, bent and tapered plagioclase twins, and poikiloblastic feldspar. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory sericite, chlorite, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
KTAA Biotite leucodiorite is a black and white coarse-grained (5-10 mm) rock with weak foliation. Microtextures consist of anhedral grain shape, feldspar alteration and zoning, undulose extinction in quartz, and rounded plagioclase feldspar grains. The leucodiorite contains quartz, plagioclase feldspar, potassium feldspar, and biotite, with accessory sericite, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
KT AB Muscovite-biotite monzodiorite is a grey medium-grained (1-5 mm) rock. Microtextures consist of anhedral grain shape, feldspar alteration and zoning, chlorite replacement ofbiotite, undulose extinction in quartz, and poikiloblastic feldspar. The monzodiorite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory sericite, chlorite, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
KTAC Tourmaline-muscovite-biotite granite is a white medium-grained (1-5 mm) rock. Microtextures consist of anhedral grain shape, feldspar alteration and zoning, chlorite replacement of biotite, undulose extinction in quartz, and poikiloblastic feldspar. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, muscovite, and tourmaline, with accessory sericite, chlorite, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
KTAD Biotite-hornblende granite is a pink medium-grained (1-5 mm) rock with weak foliation and weak mineral-aligninent lineation. Microtextures consist of anhedral grain shape, myrmekite, feldspar alteration and zoning, recrystallized quartz, and undulose extinction in quartz. The granite contains quartz, 98 plagioclase feldspar, potassium feldspar, biotite, and hornblende, with accessory sericite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
KTAE Biotite-hornblende quartz monzodiorite is a black and pink fine-grained(< 1 mm) rock with internal foliation and feldspar porphyroblasts (2-15 mm). Microtextures consist of anhedral grain shape, myrmekite, feldspar alteration and zoning, chlorite replacement of biotite, undulose extinction in quartz, tapered plagioclase twins, recrystallized quartz, and equant poikiloblastic feldspar. The quartz monzodiorite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and hornblende, with accessory sericite, chlorite, sphene, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
KTAF Muscovite-biotite granite is a grey fine-grained{< 1 mm) rock. Microtextures consist of anhedral grain shape, feldspar alteration and zoning, chlorite replacement ofbiotite, and undulose extinction in quartz. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory sericite, chlorite, apatite, zircon, and opaque. Appendix B lists the whole rock geochemical data.
KTAG Garnet-biotite-muscovite phyllite is a grey fine-grained ( < 1 mm) rock with foliation, elongation and mineral-alignment lineation, and garnet and biotite porphyroblasts (1-5 mm). Microtextures consist of anhedral grain shape that defines wavy SSPO and LPO of very fine-grained muscovite, crenulation cleavage, grey-green color replacement in biotite porphyroblasts, undulose extinction in quartz, folded quartz veins, recrystallized quartz, and poikiloblastic garnet and biotite with relict foliation. The phyllite contains quartz, garnet, biotite, and muscovite with accessory zircon and opaque.
KTAH Hornblende-muscovite-talc schist is a dark grey fine-grained(< 1 mm) rock with foliation and elongation lineation. Microtextures consist of anhedral grain shape that defines wavy SSPO and LPO of talc, folding, radiating and poikiloblastic 99 amphibole. The schist contains muscovite, talc, and hornblende, with accessory calcite, apatite, opaque, and possible corundum.
Quest Cliffs QCD Dolerite is a dark fine-grained(< 1 mm) rock.
QCE Dolerite is a dark medium-grained (1-5 mm) rock.
QCF Dolerite is a dark medium-grained (1-5 mm) rock. Microtextures consist of subhedral grain shape, plagioclase feldspar zoning, lath-shaped plagioclase feldspar, and subophitic growth of pyroxene and plagioclase. The dolerite contains plagioclase feldspar and pyroxene, with accessory opaque.
QCG Dolerite is a dark medium-grained (1-5 mm) rock. Microtextures consist of subhedral grain shape, plagioclase feldspar zoning, lath-shaped plagioclase feldspar, and subophitic growth of pyroxene and plagioclase. The dolerite contains plagioclase feldspar and pyroxene, with accessory opaque.
Sanford Cliffs SCD Dolerite is a dark medium-grained (1-5 mm) rock.
SCE Dolerite is a dark fine-grained(< 1 mm) rock. Microtextures consist of subhedral grain shape, plagioclase feldspar zoning, lath-shaped plagioclase feldspar, and subophitic growth of pyroxene and plagioclase. The dolerite contains plagioclase feldspar and pyroxene, with accessory opaque.
SCF Dolerite is a dark fine-grained (< 1 mm) rock.
SCG Sandstone is a light grey fine-grained(< 1 mm) rock with cross-bedding. Microtextures consist of anhedral grain shape, feldspar alteration and zoning and very fine-grained matrix. The sandstone contains quartz, plagioclase feldspar, potassium feldspar, and biotite, with accessory sericite, apatite, zircon, and opaque.
100 SCH Shale is a dark grey fine-grained (< 1 mm) rock.
Gargoyle Ridge GR-1 Calcareous spotted phyllite is a dark fine-grained(< 1 mm) rock with foliation, mineral-alignment lineation, folding, and dark porphyroblasts (1-2 mm).
GR-2 Sandstone is a grey fine-grained(< 1 mm) massive rock.
GR-3 Limestone is a dark fine-grained(< 1 mm) recrystallized rock with calcite veins.
GR-4 Calcite vein is a white fine-grained(< 1 mm) vein.
GR-5 Calcareous spotted phyllite is a silver fine-grained(< 1 mm) rock with foliation, elongation lineation, folding, and black porphyroblasts ( 1 mm).
GR-6 Limestone is a tan fine-grained(< 1 mm) rock.
GR-7 Sandstone is a purple fine-grained(< 1 mm) massive rock.
GR-8 Limestone is a dark fine-grained ( < 1 mm) recrystallized rock.
GR-9 Micritic limestone is a grey to buff fine-grained(< 1 mm) rock.
GR-10 Limestone is a dark fine-grained ( < 1 mm) crystalline rock with carbonate and silicate veins.
GR-11 Quartz vein is a white quartz vein.
GR-12 Quartz vein is a white quartz vein.
GR-13 Calcareous spotted phyllite is a silver fine-grained(< 1 mm) rock with foliation, elongation and mineral-alignment lineation, and black porphyroblasts (1-10 mm).
101 GR-14 Calcareous spotted phyllite is a silver fine-grained(< 1 mm) rock with foliation, elongation lineation, and black porphyroblasts (1-3 mm).
GR-15 Calcareous spotted phyllite is a silver fine-grained(< 1 mm) rock with foliation, elongation and mineral-alignment lineation, and black porphyroblasts ( 1-10 mm).
GR-16 Muscovite-biotite phyllite is a dark fine-grained(< 1 mm) non-calcareous rock with foliation, elongation lineation, and biotite porphyroblasts (1 mm). Microtextures consist of subhedral grain shape that defines planar SSPO and LPO of very fine-grained muscovite, undulose extinction in quartz and poikiloblastic biotite and opaque with relict foliation. The phyllite contains quartz, biotite, muscovite, and possible feldspar, with accessory zircon and opaque.
GR-17 Limestone is a dark fine-grained(< 1 mm) recrystallized rock.
GR-18 Muscovite-biotite meta-sandstone is a dark fine-grained(< 1 mm) rock with weak foliation, weak mineral-alignment lineation, and biotite porphyroblasts (1 mm). Microtextures consist of anhedral grain shape, feldspar alteration and zoning, chlorite replacement of biotite, and poikiloblastic biotite. The meta- sandstone contains quartz, feldspar, biotite, and muscovite, with accessory sericite, chlorite, apatite, zircon, and opaque.
GR-19 Muscovite-biotite phyllite is a silver fine-grained(< 1 mm) rock with foliation, elongation lineation, and biotite porphyroblasts (1-10 mm). Microtextures consist of anhedral grain shape that defines wavy SSPO and LPO of very fine- grained muscovite, crenulation cleavage, chlorite replacement ofbiotite, and poikiloblastic biotite with relict foliation. The phyllite contains quartz, potassium feldspar, biotite, and muscovite, with accessory chlorite, zircon, and opaque.
102 GR-20 Limestone is a grey fine-grained(< 1 mm) rock.
GR-21 Limestone is a buff fine-grained(< 1 mm) rock.
GR-22 Limestone is a dark fine-grained ( < 1 mm) recrystallized rock with calcite veins.
GR-23 Limestone is a dark fine-grained(< 1 mm) recrystallized rock with calcite veins.
GR-24 Calcite vein is a buff calcite vein.
Cambrian Bluff CB-1 Plagioclase porphyritic leucogabbro norite is a black and white medium- grained (1-5 mm).
CB-2 Dolerite is a grey and black medium to coarse-grained (1-10 mm) rock. Microtextures consist of anhedral grain shape, feldspar alteration and zoning, chlorite replacement of biotite, and tapered plagioclase twins. The dolerite contains plagioclase feldspar, potassium feldspar, biotite, and pyroxene, with accessory chlorite, apatite, zircon, and opaque.
CB-3 Granite is a pink medium-coarse-grained (1-10 mm) rock. CB-4 Gabbro is a dark grey medium-grained (1-5 mm) rock rich in plagioclase feldspar and biotite.
CB-5 Muscovite-biotite granite is a white medium to coarse-grained (1-10 mm) rock. Microtextures consist of anhedral grain shape, myrmekite, feldspar alteration and zoning, prehnite and chlorite replacement ofbiotite, undulose extinction in quartz, poikilitic feldspar. The granite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and muscovite, with accessory prehnite, sericite, chlorite, zircon, and opaque.
CB-6 Dolerite is a dark brown fine-grained(< 1 mm) rock with vesicles(< 1 mm).
103 CB-7 Limestone is a dark brown fine-grained(< 1 mm) rock with calcite clasts (1-15 mm).
CB-8 Limestone is a dark brown fine-grained ( < 1 mm) rock with calcite clasts (1-70 mm).
CB-9 Plagioclase porphyritic leucogabbro norite is a light grey medium-coarse- grained (1-10 mm) rock.
CB-10 Limestone is a dark fine-grained(< 1 mm) rock with calcite vein.
CB-11 Limestone is a dark fine-grained(< 1 mm) rock with calcite vein.
CB-12 Oolitic limestone is a light grey fine-grained(< Imm) calcareous rock.
CB-13 Plagioclase porphyritic leucogabbro norite is a black and white medium- grained (1-5 mm) rock. Microtextures consist of anhedral grain shape, feldspar alteration and zoning, tapered and bent plagioclase feldspar twins, replacement, and a calcite vein. The leucogabbro norite contains quartz, plagioclase feldspar, biotite, and pyroxene, with accessory sericite, chlorite, calcite, apatite, and opaque.
CB-14 Limestone is a dark fine-grained(< 1 mm) rock with minor calcite veins.
CB-15 Gabbro is a black-brown medium-grained (1-5 mm) rock rich in plagioclase feldspar.
CB-16 Gabbro is a black-brown medium-grained (1-5 mm) rock rich in plagioclase feldspar.
CB-17 Plagioclase porphyritic leucogabbro norite is a dark green and peach medium- grained (1-5 mm) rock. Microtextures consist of anhedral grain shape, feldspar alteration and zoning, myrmekite, and chlorite replacement of biotite. The
104 leucogabbro norite contains quartz, plagioclase feldspar, biotite, muscovite, and pyroxene, with accessory sericite, chlorite, apatite, zircon, and opaque.
CB-18 Marble tectonite is a buff and black fine-grained(< 1 mm) foliated rock.
CB-19 Marble tectonite is a rose fine-grained(< 1 mm) rock with strong foliation.
CB-20 Limestone is a buff and dark mottled fine-grained(< 1 mm) rock.
CB-21 Limestone is an orange-red fine-grained(< 1 mm) rock.
CB-22 Limestone is a buff and dark fine-grained(< 1 mm) rock.
CB-23 Gabbro is a grey medium-grained (2-4 mm) rock rich in plagioclase feldspar and biotite.
CB-24 Marble is a massive grey and buff fine-grained(< 1 mm) rock.
CB-25 Limestone is a dark fine-grained(< 1 mm) rock with minor calcite veins and weak foliation.
CB-26 Limestone is a buff fine-grained(< 1 mm) rock.
CB-27 Marble tectonite is a grey and white fine-grained(< 1 mm) rock. CB-28 Limestone is a peach fine-grained(< 1 mm) rock with calcite veins.
CB-29 Limestone is a black fine-grained(< 1 mm) rock.
CB-30 Hornblende-biotite granodiorite is a dark brown and peach medium-grained (1- 5 mm) rock. Microtextures consist of anhedral grain shape, feldspar alteration, zoning of feldspars, undulose extinction in quartz, and poikiloblastic amphibole. The granodiorite contains quartz, plagioclase feldspar, potassium feldspar, biotite, and hornblende, with accessory sericite, sphene, apatite, zircon, and opaque.
105 CB-31 Shale is a dark brown fine-grained(< 1 mm) rock with vesicles (1-4 mm).
CB-32 Calcareous conglomerate is a dark fine-grained ( < 1 mm) rock with quartz and carbonate pebbles (1-30 mm).
CB-33 Granodiorite is a dark brown fine-grained ( < 1 mm) rock with medium-grained phenocrysts (2-4 mm).
106 Appendix B Whole-Rock Geochemical Data AGJ AGK AGL AGM AGT AGT* Gneiss Granite Dolerite Dolerite Pegmatite Pegmatite Si02 65.33 75.07 54.13 55.04 74.66 74.51 Ti02 0.73 0.19 0.67 0.81 bd bd Al203 17.04 13.34 14.71 14.38 14.83 14.81 Fe203 4.92 1.53 10.07 11.50 0.58 0.58 MnO 0.04 0.03 0.17 0.17 0.13 0.13 MgO 1.83 0.36 6.62 5.66 bd bd Cao 4.29 1.02 10.56 9.10 0.18 0.18 Na20 3.03 3.25 1.92 1.99 5.10 5.14 K20 1.91 4.82 0.86 1.14 5.02 5.03 P20s 0.24 0.07 0.10 0.13 0.09 0.09 LOI 0.59 0.26 0.48 0.74 0.16 0.16 Sum 99.95 99.93 100.29 100.68 100.75 100.62
Sc 13 2 45 45 bd v 53 15 239 253 1 Cr 40 8 143 104 4 Co 8 3 45 45 1 Ni 18 8 89 80 bd Cu 13 5 89 91 12 Zn 42 31 77 87 12 Ga 20 15 16 18 18 Rb 60 172 34 42 657 Sr 269 676 128 129 3 y 19 5 22 24 bd Zr 235 166 92 129 6 Nb 11 9 6 7 8 Ba 640 1952 208 268 9 La 35 29 9 12 5 Ce 62 71 20 28 13 Pb 9 78 9 10 37 Th 13 18 4 6 bd u 3 bd 3 4 4
Major elements are in weight percent of oxides and trace elements are in ppm concentration *Re-fused bead; bd =below detection levels LOI = Loss on Ignition
107 MRD MRE MRF MRK MRM MRN MRP Granite Granite Dolerite Dolerite Dolerite Dolerite Gneiss Si02 73.26 73.98 55.41 54.49 53.40 56.95 70.44 Ti02 0.21 0.09 0.81 0.61 0.61 1.00 0.23 Al203 14.10 14.50 14.53 14.78 14.70 12.99 15.39 Fe20 3 1.80 1.05 11.21 9.90 10.56 12.37 1.91 MnO 0.04 0.01 0.18 0.17 0.18 0.19 0.03 MgO 0.35 0.16 5.10 7.64 6.48 4.30 0.42 cao 1.49 1.22 9.88 10.56 10.80 8.41 1.29 Na20 . 4.13 4.37 2.21 1.81 2.04 2.20 5.10 K20 4.68 4.76 1.05 0.76 0.78 1.33 3.85 P20s 0.06 0.02 0.12 0.09 0.09 0.15 0.06 LOI 0.21 0.36 0.44 0.10 0.13 0.84 0.49 Sum 100.32 100.53 100.92 100.92 99.76 100.72 99.21
Sc 2 3 45 42 47 46 2 v 19 7 254 234 253 279 16 Cr 7 5 27 218 126 10 4 Co 2 2 46 48 48 46 2 Ni 7 6 57 109 85 44 7 Cu 6 9 101 76 101 146 6 Zn 18 17 86 76 81 100 53 Ga 16 20 17 15 16 17 19 Rb 160 113 40 29 29 51 98 Sr 750 641 121 121 130 113 1665 y 15 20 26 20 20 31 6 Zr 215 96 112 87 81 148 186 Nb 20 13 7 6 5 9 4 Ba 1667 971 250 186 186 311 2554 La 75 10 12 7 8 16 62 Ce 146 37 27 17 17 28 128 Pb 43 55 9 6 9 13 22 Th 56 8 6 4 4 6 3 u 6 4 1 bd
108 MRQ MRU MRY TNG TNG-A TNH TNK Gneiss Granodiorite Gneiss Granite Granite Dolerite Granite Si02 64.42 70.38 63.75 73.76 54.61 74.29 Ti02 0.55 0.52 0.59 0.20 0.60 0.18 Al203 15.56 15.29 15.46 13.08 14.65 14.07 Fe203 4.66 3.60 4.75 1.73 9.33 1.05 MnO 0.08 0.04 0.08 0.03 0.17 0.03 MgO 1.55 1.08 1.62 0.37 6.53 0.19 Cao 3.15 2.59 3.27 0.84 10.80 0.66 Na20 4.39 3.65 4.19 2.63 1.77 2.92 K20 4.75 3.10 5.02 6.41 0.84 6.34 P20s 0.38 0.15 0.44 0.06 0.09 0.23 LOI 0.59 0.22 0.37 0.58 0.53 0.45 Sum 100.06 100.60 99.55 99.68 99.92 100.40
Sc 5 8 7 3 3 45 3 v 58 38 65 6 5 251 5 Cr 11 25 14 4 4 89 4 Co 6 7 8 2 2 47 2 Ni 12 14 13 5 5 78 1 Cu 8 16 8 11 10 63 3 Zn 44 78 53 44 45 74 38 Ga 18 20 18 17 18 16 18 Rb 160 95 160 341 342 34 478 Sr 1511 169 1467 126 126 122 33 y 25 24 28 33 33 21 28 Zr 335 147 363 148 149 95 59 Nb 20 10 23 18 18 7 9 Ba 4102 460 3738 352 354 197 123 La 204 18 198 52 52 8 23 Ce 361 43 356 127 127 19 56 Pb 49 28 50 67 65 7 50 Th 63 7 64 52 53 4 8 u bd 2 bd 10 9 14
109 Samele TNQ TNR TNS KTJ KTK KTK-A KTW Granite Granite Granite Granite Granite Granite Granite Si02 67.01 73.21 73.95 74.54 68.21 76.79 Ti02 0.64 0.20 0.24 0.11 0.35 0.14 Al203 14.97 14.21 14.33 14.32 15.54 12.24 Fe203 4.51 1.16 1.33 0.98 2.92 0.93 MnO 0.08 0.03 0.05 0.02 0.06 0.01 MgO 0.85 0.24 0.28 0.23 0.97 0.22 Cao 1.67 0.78 0.69 1.10 2.22 0.57 Na20 3.87 2.85 2.62 3.86 4.60 3.05 K20 4.98 5.96 5.86 5.10 4.72 5.29 P20s 0.19 0.18 0.18 0.04 0.14 0.01 LOI 0.98 0.71 0.87 0.06 0.23 0.30 Sum 99.73 99.54 100.41 100.35 99.96 99.55
Sc 9 4 4 2 4 4 1 v 22 7 6 9 36 35 8 Cr 5 4 5 7 18 18 3 Co 10 bd 2 2 4 4 2 Ni 11 1 1 6 13 12 8 Cu 11 4 5 16 5 6 16 Zn 91 51 59 17 27 27 13 Ga 19 20 21 16 19 18 16 Rb 160 475 490 188 101 101 87 Sr 260 35 30 272 1062 1062 181 y 90 22 22 10 26 26 10 Zr 440 90 110 81 289 288 328 Nb 23 11 13 10 23 23 4 Ba 1029 143 132 1257 2437 2443 1212 La 86 30 29 16 86 89 73 Ce 180 77 77 43 159 161 155 Pb 33 48 45 46 32 35 16 Th 24 12 17 5 39 39 11 u 5 10 11 7 bd bd 2
110 KTZ KTAA KTAB KTAC KTAD KTAE KTAF Quartz Granite Leucodiorite Monzodiorite Granite Granite monzodiorite Granite Si02 72.31 60.07 60.23 73.62 75.13 62.66 73.07 Ti02 0.32 0.50 0.61 0.12 0.20 0.88 0.31 Al203 14.15 21.96 20.73 14.94 11 .61 16.24 14.62 Fe203 2.41 2.49 5.04 0.98 3.22 5.82 1.39 MnO 0.04 0.02 0.05 0.02 0.04 0.07 0.01 MgO 0.65 1.20 1.70 0.21 0.04 2.20 0.37 cao 2.30 4.93 4.78 0.96 0.98 3.58 1.29 Na20 3.16 6.91 4.75 3.41 2.57 4.41 3.62 K20 3.89 1.48 2.26 5.35 5.64 3.61 4.93 P20s 0.10 0.11 0.18 0.12 0.01 0.43 0.06 LOI 0.36 0.53 0.59 0.59 0.13 0.32 0.46 Sum 99.70 100.21 100.91 100.32 99.57 100.23 100.13
Sc 5 3 12 3 8 9 v 18 42 33 4 4 85 7 Cr 13 9 24 6 3 30 4 Co 5 8 6 3 11 2 Ni 6 17 12 2 4 22 5 Cu 4 9 5 5 4 29 6 Zn 53 44 112 49 72 75 52 Ga 21 29 23 25 21 21 21 Rb 238 54 136 374 164 150 264 Sr 145 876 309 87 16 810 252 y 18 6 27 14 70 39 4 Zr 137 284 180 57 331 310 206 Nb 12 2 11 8 34 18 8 Ba 343 648 465 253 46 2041 822 La 21 9 32 12 145 136 31 Ce 47 28 59 40 326 228 58 Pb 56 20 29 86 29 22 42 Th 13 bd 7 3 36 26 20 u 4 4 3 6 5 bd 2
111 Appendix C Mineral Composition Data Table 2. Average analyses of biotite.
Samele AGO AGE AGE* AGF AGG AGG* AGH MRH MRJ MRT TNE TNF Si02 36.29 37.34 37.43 35.50 38.16 37.28 36.84 37.14 36.52 36.61 33.85 34.81 Ti02 4.75 4.87 3.96 0.52 3.10 3.37 5.41 3.30 4.08 2.34 1.21 1.98 Al203 18.11 17.83 17.34 22.52 18.60 18.63 15.92 18.57 17.98 16.53 20.53 20.63 MgO 11.56 15.60 17.27 9.65 17.29 14.63 12.74 14.08 14.10 13.52 7.71 7.24 FeO 16.20 11 .21 9.64 18.31 9.28 12.56 16.39 12.56 13.05 18.18 23.59 23.36 MnO 0.02 0.00 0.04 0.12 0.00 0.01 0.03 0.01 0.03 0.04 0.03 0.13 Cao 0.01 0.03 0.01 0.05 0.02 0.01 0.01 0.01 0.02 0.11 0.02 0.03 Na20 0.09 0.12 0.36 0.14 0.10 0.09 0.08 0.11 0.05 0.23 0.32 0.35 K20 10.06 9.82 9.44 9.62 9.88 9.96 10.03 9.99 10.00 8.57 7.76 8.73 total 97.07 96.82 95.50 96.43 96.44 96.54 97.45 95.76 95.82 96.14 95.02 97.25
Cations {calculated on the basis of 11 OX}'.gens all Fe as Si 2.678 2.692 2.714 2.643 2.729 2.709 2.716 2.722 2.689 2.736 2.616 2.633 Ti 0.264 0.264 0.216 0.029 0.167 0.184 0.300 0.182 0.226 0.132 0.070 0.112 Al 1.575 1.515 1.482 1.977 1.568 1.596 1.384 1.604 1.561 1.456 1.870 1.839 Mg 1.272 1.677 1.867 1.071 1.843 1.585 1.401 1.539 1.548 1.506 0.888 0.816 Fe 1.000 0.676 0.585 1.140 0.555 0.763 1.011 0.770 0.803 1.136 1.525 1.478 Mn 0.001 0.000 0.002 0.008 0.000 0.000 0.002 0.000 0.002 0.003 0.002 0.008 Ca 0.000 0.002 0.001 0.004 0.001 0.001 0.001 0.001 0.002 0.009 0.002 0.002 Na 0.013 0.016 0.051 0.020 0.013 0.013 0.011 0.015 0.008 0.034 0.048 0.051 K 0.947 0.904 0.873 0.914 0.901 0.924 0.944 0.934 0.939 0.817 0.765 0.842 total 7.750 7.746 7.791 7.806 7.778 7.777 7.769 7.768 7.778 7.830 7.785 7.782
100 Mg/(Mg +Fe) 56.0 71.3 76.2 48.4 76.9 67.5 58.1 66.6 65.8 57.0 36.8 35.6
...... * mineral composition inside garnet; all other mineral compositions are outside garnet ...... N Table 3: Average analyses of garnet.
SamE!le AGO AGO* AGE AGE* AGF AGG AGG* AGH AGH* MRH MRH* MRH**
Si02 37.88 38.48 38.37 39.08 37.26 38.63 39.24 38.26 38.46 38.70 39.12 39.24
Ti02 0.01 0.01 0.04 0.06 0.00 0.02 0.02 0.01 0.05 0.00 0.02 0.03
Al20 3 22.13 22.95 22.81 22.68 22.16 23.11 23.07 22.33 22.60 22.66 23.18 22.93 MgO 5.46 7.74 7.73 8.44 2.91 7.41 9.45 6.30 5.75 6.81 9.07 9.10 FeO 31.81 28.49 29.54 23.93 31 .90 30.26 26.46 29.03 25.92 30.85 27.65 27.19 MnO 0.69 0.39 0.45 0.32 5.22 0.50 0.33 0.77 0.56 0.39 0.27 0.25 cao 2.53 2.48 1.26 5.91 1.48 1.34 2.61 4.01 7.56 1.18 0.95 1.37
Na20 0.00 0.01 0.01 0.02 0.03 0.02 0.02 0.02 0.00 0.03 0.03 0.00
K20 0.03 0.02 0.03 0.01 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.02
Cr20 3 0.01 0.03 0.10 0.21 0.01 0.03 0.03 0.02 0.02 0.02 0.03 0.00 total 100.56 100.62 100.34 100.68 101 .01 101 .35 101.24 100.77 100.95 100.66 100.35 100.14
Cations (calculated on the basis of 12 assuming all Fe as FeO) Si 2.971 2.960 2.966 2.971 2.965 2.963 2.968 2.968 2.962 2.995 2.986 2.998 Ti 0.001 0.000 0.002 0.004 0.000 0.001 0.001 0.001 0.003 0.000 0.001 0.001 Al 2.046 2.081 2.078 2.033 2.079 2.090 2.056 2.042 2.051 2.067 2.085 2.065 Mg 0.639 0.888 0.891 0.957 0.345 0.845 1.066 0.728 0.660 0.786 1.032 1.037 Fe 2.087 1.833 1.910 1.522 2.123 1.943 1.674 1.884 1.669 1.997 1.765 1.737 Mn 0.046 0.026 0.030 0.020 0.352 0.032 0.021 0.051 0.037 0.025 0.018 0.016 Ca 0.213 0.205 0.105 0.481 0.127 0.110 0.212 0.333 0.624 0.097 0.078 0.112 Na 0.000 0.002 0.001 0.003 0.004 0.003 0.003 0.004 0.000 0.004 0.004 0.001 K 0.003 0.002 0.003 0.001 0.003 0.003 0.002 0.002 0.002 0.002 0.002 0.002 Cr 0.001 0.002 0.006 0.013 0.000 0.002 0.002 0.001 0.001 0.001 0.002 0.000 total 8.007 8.000 7.992 8.005 7.999 7.993 8.004 8.012 8.010 7.974 7.973 7.969
mol%Alm 0.699 0.621 0.651 0.511 0.727 0.635 0.563 0.629 0.558 0.687 0.610 0.599 molo/o Pyr 0.214 0.301 0.304 0.321 0.121 0.318 0.360 0.243 0.221 0.270 0.357 0.357 molo/o Grs 0.071 0.069 0.036 0.161 0.036 0.037 0.070 0.111 0.209 0.034 0.027 0.039 molo/o S[:!s 0.015 0.009 0.010 0.007 0.116 0.010 0.007 0.017 0.012 0.009 0.006 0.005
1 OOMg/{Mg+Fe) 23.4 32.6 31.8 38.6 14.0 30.3 38.9 27.9 28.3 28.2 36.9 37.4
,__. all compositions are from rims unless noted otherwise; * garnet core composition; **garnet composition near plagioclase ,__. w Table 4: Average analyses of garnet continued.
Samele MRJ MRJ* MRT MRT* TNE TNE* TNF KTF Si02 38.73 39.19 37.88 38.27 36.86 36.79 37.34 38.48 Ti02 0.00 0.01 0.02 0.03 0.09 0.16 0.02 0.04 Al203 22.94 23.10 22.26 22.52 21 .75 21.78 21.96 22.01 MgO 7.47 9.48 3.28 4.74 1.88 1.00 1.88 4.96 FeO 30.02 26.95 30.17 27.46 38.97 32.77 35.10 22.02 MnO 0.47 0.36 1.22 0.63 0.35 5.24 3.46 2.13 Cao 1.26 1.56 6.36 7.19 1.33 2.90 1.71 10.94 Na20 0.01 0.01 0.01 0.02 0.03 0.03 0.05 0.02 K20 0.02 0.02 0.03 0.02 0.02 0.02 0.02 0.00 Cr20 3 0.05 0.01 0.01 0.01 0.00 0.02 0.01 0.02 total 100.976 100.69 101.24 100.88 101.28 100.70 101.55 100.63
Cations (calculated on the basis of 12 assuming all Fe as FeO) Si 2.977 2.978 2.968 2.969 2.960 2.966 2.977 2.973 Ti 0.000 0.000 0.001 0.002 0.005 0.010 0.001 0.003 Al 2.079 2.069 2.056 2.059 2.058 2.069 2.063 2.005 Mg 0.856 1.074 0.384 0.548 0.225 0.120 0.223 0.571 Fe 1.930 1.713 1.977 1.781 2.616 2.210 2.340 1.423 Mn 0.031 0.023 0.081 0.041 0.023 0.358 0.234 0.140 Ca 0.104 0.127 0.534 0.597 0.114 0.250 0.146 0.905 Na 0.002 0.002 0.001 0.003 0.004 0.004 0.007 0.003 K 0.002 0.002 0.003 0.002 0.003 0.002 0.002 0.000 Cr 0.003 0.001 0.001 0.001 0.000 0.001 0.001 0.001 total 7.984 7.989 8.005 8.002 8.009 7.992 7.995 8.023
mol%Alm 0.661 0.583 0.666 0.600 0.878 0.752 0.795 0.468 mol% Pyr 0.293 0.366 0.129 0.184 0.075 0.041 0.076 0.188 mol% Grs 0.035 0.043 0.178 0.202 0.038 0.085 0.050 0.298 mol% S_e.s 0.011 0.008 0.027 0.014 0.008 0.122 0.079 0.046
100Mg/(Mg+Fe) 30.7 38.5 16.3 23.5 7.9 5.2 8.7 28.6
...... all compositions are from rims unless noted otherwise; *garnet core composition; **garnet composition near plagioc ...... +:>. Table 5. Average analyses of muscovite. Table 6. Average analyses of staurolite. Table 7. Average analyses of pyroxene.
Sample TNE Sample TNE Sample MRT Si02 45.99 Si02 27.05 Si02 51.04 Ti02 0.25 Ti02 0.48 Ti02 0.20 Al20 3 36.97 Al203 56.38 Al20 3 2.57 MgO 0.41 MgO 1.31 MgO 11 .79 FeO 0.77 FeO 14.72 FeO 13.67 MnO 0.01 MnO 0.03 MnO 0.18 Cao 0.02 Cao 0.00 Cao 20.59 Na20 1.50 Na20 0.05 Na20 0.19 K20 9.11 K20 0.03 K20 0.05 total 95.03 Cr20 3 0.01 Cr20 3 0 total 100.07 total 100.27
Cations (calculated on the basis of Cations (calculated on the basis of Cations (calculated on the basis of 11 oxygens assuming all Fe as FeO) 48 oxygens assuming all Fe as FeO) 6 oxl'.gens assuming all Fe as FeO) Si 3.042 Si 7.689 Si 1.934 Ti 0.012 Ti 0.104 Ti 0.006 Al 2.883 Al 18.886 Al 0.115 Mg 0.041 Mg 0.556 Mg 0.666 Fe 0.042 Fe 3.499 Fe 0.433 Mn 0.001 Mn 0.006 Mn 0.006 Ca 0.002 Ca 0.000 Ca 0.836 Na 0.192 Na 0.029 Na 0.014 K 0.769 K 0.011 K 0.002 total 6.984 Cr 0.003 Cr 0.000 total 30.783 total 4.011
100 Mg/(Mg + Fe) 96.0 100 Mg/(Mg +Fe) 13.7 100 Mg/(Mg +Fe) 60.6
,_. ,_. VI Table 8. Average analyses of amphibole. Table 9. Average An content of plagioclase.
Sample KTF Sample An content Si02 42.64 AGO 0.32 Ti02 1.12 AGO* 0.31 Al203 12.60 AGE 0.32 MgO 10.58 AGF 0.30 FeO 16.61 AGG 0.32 MnO 0.32 AGG* 0.40 Cao 11.94 AGH 0.46 Na20 1.70 AGH* 0.49 K20 0.75 MRH 0.24 total 98.27 MRH* 0.36 MRJ 0.28 Cations (calculated on the basis of MRT 0.96 23 oxygens assuming all Fe as FeO) TNF 0.10 Si 6.362 KTF 0.53 Ti 1.879 Al 0.167 Mg 1.578 * mineral composition inside garnet Fe 2.478 all other mineral compositions are outside garnet Mn 0.048 Ca 1.782 Na 0.254 K 0.112 total 14.661
100 Mg/(Mg +Fe) 0.4
0\- Appendix D Rock Magnetic Susceptibility Data All values are reported in 10-3 cgs units
Non- Rock Weathered Sample Rock Name weathered Type Surface* Surface* AGO Sil-crd-grt-bt gneiss M 0.06 AGE Grt-bt gneiss M 0.02 0.03 AGF Sil-grt-bt gneiss M 0.02 0.02 AGG Grt-bt gneiss M 0.02 0.02 AGH Ky-grt-bt gneiss M 0.02 AGI Grt-bt gneiss M 0.01 0.01 AGJ Sil-ms-grt-bt gneiss M 0.02 AGK Ms-bt granite 0.00 AGL Dolerite 0.45 0.38 AGM Dolerite 1.00 0.81 AGN Bt-px gneiss M 0.05 0.04 AGO Grt-bt schist M 0.00 0.02 AGP Sil-grt-bt-ms schist M 0.10 0.03 AGQ Bt-hbl gneiss M 0.02 AGR Ky-sil-grt-bt gneiss M 0.03 AGS Grt-px-hbl-bt gneiss M 0.02 0.03 AGT Grt-ms pegmatite 0.00
MRD Hbl-bt granite 0.89 0.78 MRE Ms-bt granite 0.00 MRF Dolerite 0.83 0.72 MRG Grt-bt gneiss M 0.02 MRH Ky-sil-grt-bt gneiss M 0.02 MRI Hbl-bt gneiss M 0.71 MRJ Sil-grt-bt gneiss M 0.01 MRK Dolerite I 0.34 0.30 MRL Ms-bt gneiss M 0.01 MRM Dolerite I 0.43 MRN Dolerite I 1.10 MRO Grt-ms-bt gneiss M 0.05 MRP Ms-bt gneiss M 0.00 MRQ Bt-hbl gneiss M 2.10 MRR Hbl-bt gneiss M 1.10 MRS Sil-grt-bt schist M 0.00 MRT Eclogite M 0.10 0.08 MRU Grt-ms-bt granodiorite 0.01 0.02
I =Igneous Rock M =Metamorphic Rock S =Sedimentary Rock
* reported values are the average of 10 measurements (see text). 117 Non- Rock Weathered Sample Rock Name weathered Type Surface Surface MRV Bt gneiss M 0.64 MRW Grt-ms-bt gneiss M 0.00 MRX Grt-ms-bt gneiss M 0.00 MRY Bt-hbl gneiss M 1.50 1.90 MRZ Ep amphibolite M 1.70 1.70 MRAA Grt amphibolite M 0.04 MRAB Grt-bt gneiss M 0.01 0.00 MRAC Ms-bt gneiss M 0.01 0.01
TND Diamictite s 0.00 0.01 TNE St-grt-bt-ms phyllite M 0.01 0.02 TNF Tour-and-grt-bt-ms phyllite M 0.02 0.02 TNG Ms-bt granite I 0.00 0.00 TNH Dolerite I 0.11 0.08 TNI Sandstone s 0.00 0.00 TNJ Bt-ms granite 0.00 0.00 TNK Tour-bt-ms granite I 0.00 0.00 TNL Ms-bt granite I 0.15 0.08 TNM Bt-ms phyllite M 0.01 0.00 TNN Ms-bt phyllitic quartzite M 0.00 0.00 TNO St-grt-ms-bt schist M 0.02 0.00 TNP Tour-bt-ms schist M 0.00 0.00 TNQ Ms-bt granite 0.27 0.30 TNR Tour-bt-ms granite 0.00 0.00 TNS Tour-bt-ms granite 0.00 0.00
KTD Bt-ms meta-sandstone M 0.00 0.01 KTE Chl-hbl gneiss M 0.05 0.03 KTF Grt amphibolite M 2.10 1.80 KTG Ms-bt spotted phyllite M 0.08 0.07 KTH Cal-bt schist M 0.02 0.01 KTI Hbl-bt gneiss M 0.36 0.25 KTJ Bt granite 0.00 0.00 KTK Hbl-bt granite 0.74 0.69 KTL Grt-bt gneiss M 0.01 0.00 KTM Ms-grt-bt gneiss M 0.01 0.00 KTN Ms-grt-bt gneiss M 0.05 0.03 KTO Ms-grt-bt gneiss M 0.01 0.02 KTP Ms quartzite M 0.00 KTQ Sil-ms-bt quartzite M 0.00 KTR Tour-sil-bt-ms schist M 0.01 KTS Bt gneiss M 0.00 KTT Talc-amph marble M 0.00 KTU Grt-ms-bt gneiss M 0.00 0.00 KTV Grt-ms-hbl-bt gneiss M 1.80 1.50 KTW Ms-bt granite I 0.00 0.00 KTX Bt-ms gneiss M 0.54 0.56 118 Non- Rock Weathered Sample Rock Name weathered Type Surface Surface KTY Hbl-bt gneiss M 3.20 2.10 KTZ Ms-bt granite I 0.00 0.00 KTAA Bt leucodiorite 0.00 0.00 KTAB Ms-bt monzodiorite 0.00 0.00 KTAC Tour-ms-bt granite 0.00 0.00 KTAD Bt-hbl granite I 0.14 0.12 KTAE Bt-hbl qtz monzodiorite I 0.45 0.52 KTAF Ms-bt granite I 0.00 0.00 KTAG Grt-bt-ms phyllite M 0.00 0.00 KTAH Hbl-ms-tlc schist M 0.03 0.02
QCD Dolerite 0.57 0.49 QCE Dolerite 0.44 QCF Dolerite 0.40 0.35 QCG Dolerite 0.48 0.45
SCD Dolerite 0.16 SCE Dolerite 0.13 0.11 SCF Dolerite I 0.11 SCG Sandstone s 0.01 SCH Shale s 0.03 0.02
GR-1 Cal spotted phyllite M 0.01 GR-2 Sandstone s 0.00 GR-3 Limestone s 0.00 GR-4 Cal vein 0.00 GR-5 Cal spotted phyllite M 1.80 GR-6 Limestone s 0.00 GR-7 Sandstone s 0.00 GR-8 Limestone s 0.01 GR-9 Micritic limestone s 0.00 GR-10 Limestone s 0.03 GR-11 Qtz vein 0.00 GR-12 Qtz vein 0.00 GR-13 Cal spotted phyllite M 2.40 GR-14 Cal spotted phyllite M 0.42 GR-15 Cal spotted phyllite M 1.40 GR-16 Ms-bt phyllite M 0.02 GR-17 Limestone s 0.71 GR-18 Ms-bt meta-sandstone 0.02 0.01 GR-19 Ms-bt phyllite M 1.60 1.60 GR-20 Limestone s 0.00 GR-21 Limestone s 0.01 GR-22 Limestone s 0.02 GR-23 Limestone s 0.00 GR-24 Cal vein I 0.00
119 Non- Rock Weathered Sample Rock Name weathered Type Surface Surface CB-1 Plag porphyry leucogabbro norite I 0.02 CB-2 Dolerite I 0.03 CB-3 Granite I 0.02 CB-4 Gabbro I 0.31 CB-5 Ms-bt granite 0.00 CB-6 Dolerite I 0.02 CB-7 Limestone s 0.01 CB-8 Limestone s 0.00 CB-9 Plag porphyry leucogabbro norite I 0.01 CB-10 Limestone s 0.00 CB-11 Limestone s 0.01 CB-12 Oolitic limestone s 0.00 CB-13 Plag porphyry leucogabbro norite I 0.03 0.03 CB-14 Limestone s 0.00 CB-15 Gabbro I 0.04 CB-16 Gabbro 0.86 CB-17 Plag porphyry leucogabbro norite I 0.03 0.03 CB-18 Marble tectonite M 0.01 CB-19 Marble tectonite M 0.02 CB-20 Limestone s 0.00 CB-21 Limestone s 0.00 CB-22 Limestone s 0.00 CB-23 Gabbro I 0.04 CB-24 Marble M 0.00 CB-25 Limestone s 0.01 CB-26 Limestone s 0.00 CB-27 Marble tectonite M 0.00 CB-28 Limestone s 0.03 CB-29 Limestone s 0.00 CB-30 Hbl-bt granodiorite 0.04 0.04 CB-31 Slate I 0.02 CB-32 Cal conglomerate s 0.01 CB-33 Granodiorite I 0.05
120