DOCSLIB.ORG

Differentiation and Alkali Metasomatism in Dike Swarm Complex and Related Igneous Rocks Near Capitan, Lincoln County, New Mexico Wolfgang E

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Differentiation and Alkali Metasomatism in Dike Swarm Complex and Related Igneous Rocks Near Capitan, Lincoln County, New Mexico Wolfgang E New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/15 Differentiation and alkali metasomatism in dike swarm complex and related igneous rocks near Capitan, Lincoln County, New Mexico Wolfgang E. Elston and Henry I. Snider, 1964, pp. 140-147 in: Ruidoso Country (New Mexico), Ash, S. R.; Davis, L. R.; [eds.], New Mexico Geological Society 15th Annual Fall Field Conference Guidebook, 195 p. This is one of many related papers that were included in the 1964 NMGS Fall Field Conference Guidebook. Annual NMGS Fall Field Conference Guidebooks Every fall since 1950, the New Mexico Geological Society (NMGS) has held an annual Fall Field Conference that explores some region of New Mexico (or surrounding states). Always well attended, these conferences provide a guidebook to participants. Besides detailed road logs, the guidebooks contain many well written, edited, and peer-reviewed geoscience papers. These books have set the national standard for geologic guidebooks and are an essential geologic reference for anyone working in or around New Mexico. Free Downloads NMGS has decided to make peer-reviewed papers from our Fall Field Conference guidebooks available for free download. Non-members will have access to guidebook papers two years after publication. Members have access to all papers. This is in keeping with our mission of promoting interest, research, and cooperation regarding geology in New Mexico. However, guidebook sales represent a significant proportion of our operating budget. Therefore, only research papers are available for download. Road logs, mini-papers, maps, stratigraphic charts, and other selected content are available only in the printed guidebooks. Copyright Information Publications of the New Mexico Geological Society, printed and electronic, are protected by the copyright laws of the United States. No material from the NMGS website, or printed and electronic publications, may be reprinted or redistributed without NMGS permission. Contact us for permission to reprint portions of any of our publications. One printed copy of any materials from the NMGS website or our print and electronic publications may be made for individual use without our permission. Teachers and students may make unlimited copies for educational use. Any other use of these materials requires explicit permission. This page is intentionally left blank to maintain order of facing pages. NEW MEXICO GEOLOGICAL SOCIETY • FIFTEENTH FIELD CONFERENCE DIFFERENTIATION AND ALKALI METASOMATISM IN DIKE SWARM COMPLEX AND RELATED IGNEOUS ROCKS NEAR CAPITAN, LINCOLN COUNTY, NEW MEXICO Wolfgang E. Elston and Henry I. Snider University of New Mexico, Albuquerque, New Mexico INTRODUCTION in some places; latite is rare and phonolite is confined to a few occurrences. The prominent dike swarm between the villages of The most important properties of the dike rocks Capitan and Nogal has attracted the attention of almost are summarized in table 1 and photomicrographs of typi- every geologist who has travelled through the area. It cal examples are shown in figure 1. Detailed studies to extends from the vicinity of Sierra Blanca some 40 miles determine exact composition of the minerals have not to the north-northeast, into the Jicarilla Mountain area. been made, and would be difficult because of alteration. The longest individual dikes are tens of feet wide and about 3 miles long, but the majority are much smaller. Their best development is around Indian Divide and the Field Relationships area immediately to the southwest. As shown in figure 2, the dikes are irregular in Air photos of the outcrop belts of the Mancos Shale, shape. They are intrusive-magmatic rather than meta- Mesaverde Group and Cub Mountain Formation show somatic, judging by the disruption of invaded rocks, hundreds of low NNE-trending ridges, marked by prom- sharp contacts, fine-grained chilled borders, and flow-lin- inent tree lines. On the ground, each ridge turns out to eation of crystals. Rhyolite has a distinct tendency to be a composite dike, made up of many individual dikes form sills in incompetent shale beds; other rock types with complex cross-cutting relationships. The ridges are tend to form dikes controlled by fractures. covered by innumerable dark boulders formed by spher- Most relative ages could be established by cross- oidal weathering of various types of diabase. Outcrops cutting relationships, but even where two dikes were par- are poor except in cuts along U.S. Highway 380 and the allel the younger could usually be recognized by its fine- abandoned railroad between Carrizozo and Capitan. grained chilled border. Also, irregular apophyses, a few The dikes show features of more than local interest. inches long, of the younger dike locally invade the older The older dikes are various types of diabase; the younger dike. dikes include both quartz-bearing rhyolite and nephe- The relationship of Type 2 to Type 1 is based on a line-bearing phonolite. The plagioclases of altered dia- single weathered outcrop (figure 2A). Microscopically, base dikes generally show replacement of labradorite by the Type 2 olivine diabase porphyry is finer-grained at oligoclase, a feature more commonly associated with the the contact than a foot away from it, indicating chilling marine spilitic volcanic rocks of eugeosynclines than with against pre-existing Type 1 rock. These age relationships dikes in a continental environment. Secondary potassi- are important because Type 2 is the most mafic rock in um feldspar occurs in some of the dikes but seems to be the complex. As for the remaining age relationships, de- more common in the nearby Carrizo Mountain stock. tailed examination of composite dikes in 21 road and There, late magmatic or post-magmatic orthoclase pro- railroad cuts failed to show any exceptions to the order gressively replaces plagioclase phenocrysts near the roof of intrusion given here. Away from artificial cuts only of the intrusion. a few outcrops show conclusive cross-cutting relation- The only previous publication on the dikes (Patton, ships, and these also follow the same sequence. In none 1951) is confined to a brief description of olivine-free of the composite dikes examined were all seven rock diabases. It lacks an discussion of field occurrences. This types seen; the sequence was pieced together from seve- article is based on field work done by Elston for the ral occurrences. The sketches in figure 2 show all rock New Mexico Bureau of Mines and Mineral Resources types except Type 7 phonolite, but a phonolite dike cuts in 1956, followed by examination of 123 thin sections by a Type 6 latite dike 0.1 mile east of the roadcut shown Elston in 1957-58 and by Snider in 1962-63. in figure 2C. DIKE ROCKS Differentiation Trends The dikes consist of seven rock types, which are, in The dikes do not follow a simple differentiation order of age: (1) labradorite-olivine diabase porphyry, trend from mafic to felsic or mafic to alkalic. If the (2) olivine diabase porphyry, (3) diabase, (4) horn- field relationships have been interpreted correctly, lab- blende-biotite diabase, (5) rhyolite, (6) latite (grading radorite-olivine diabase porphyry (Type 1) is older than into trachyte), and (7) phonolite. For brevity, these the more mafic olivine diabase porphyry (Type 2). Pos- rocks are referred to as Types 1 through 7 throughout sibly, Type 1 is representative of the parent magma and this paper. Type 2 has been enriched in early-formed crystals. The diabases, especially Types 3 and 4, are the Further differentiation would follow a clearly alkalic most abundant; rhyolite is locally abundant but absent trend ending in phonolite (Type 7) if it were not for 140 Texture Trachytic, with sparse phenocrysts of oligoclase and orthoclase. 0? OOi 0 Alteration Calcite pseudomorphous after pheno- crysts of a ferromagnesian mineral (py- P. roxene?). Secondary cancrinite and so- dalite may be present in traces around nepheline. Texture Phenocrysts (sparse in some specimens) augite up to 3.0 mm long, sparse oligo- In M clase. Groundmass felted intergrowth of tl CO ctl K-spar and albite. Alteration Secondary quartz and calcite in cavities, green biotite flakes probably from altera- tion of augite; kaolinite, sericite, chlorite, zeolite (scolecite ?) present in some spe- cimens. Texture Fine-grained (0.125 mm) flow-banded 0 0 granular aggregate of quartz and K-spar, )? 10 sparse phenocrysts of embayed quartz, 0, 0 10 CD 1-1 altered albite. Alteration Potassium feldspar partly unmixed to perthite, sericitized. Some xls. rimmed with albite. Sparse albite phenocrysts, seriticized. Secondary calcite abundant. Texture Diabasic, plagioclase phenocrysts sparse, less than 2.5 mm long. Alteration Generally fresher than diabase, but ande- sine-labradorite commonly replaced by oligoclase. Biotite formed by reaction from hornblende, secondary orthoclase, chlorite, serpentine, zeolite present. 2 Texture Fine-grained, felty groundmass, pheno- Ca crysts less than 2 mm long, less abund- In 00 ant than in other diabase types. C.? E ti - o Alteration Intensely altered. Plagioclase sericitized, 02 v-I olivine replaced by calcite and chlorite; a) N augite by secondary green biotite, more rarely by chlorite with magnetite rims. 0 Zeolite present in some specimens, also •0 trace of secondary orthoclase. P. Cacd Texture Diabasic; phenocrysts 2.5 mm long, make In 0 up 50-60% of rock, are less conspicuous in 6 outcrops than in labradorite-olivine dia- .2i a) base porphyry. .0 0 Alteration Tends to be deeply weathered. In fresh • b-0 0 specimens, olivine has magnetite rims, is .0 )42 partly serpentinized. t.) 0.) • :E Ca Texture Diabasic; conspicous phenocrysts, mainly E) >% [1] N O labradorite laths 5.0 mm long, make up I 1 ."" a) a) o IfJ Ili 30-40% of rock. „, co 1-1 .10 0 Alteration Olivine partly replaced by calcite and 0 serpentine, some crystals have magnetite :5 centers. q 0 ;.-1 o o .cn cd E 1.
Load more

Recommended publications
  • University Ox Nevada Reno Geology, Geotechnical Properties And
    University ox Nevada - Reno Reno Reno, Key; ;v5 57 geology, Geotechnical Properties and Vesicular Rock Classification of 1onsetown Basalts and Latites, Truckee Area, California A thesis submitted in partial fulfillment ox the requirements for the degree of Master of Science in Geological Engineering far L J Joseph G. Franzone May 1980 HftWttiS U M A I 'f fj'h.i s thesis of Joseph 0. Iran zone is approved: University of Revada. Reno May 19B0 ii ACKNOW LEBGEMENT 3 I am indebted to several people for the assistance and encouragement they gave me dui’ing the preparation of this thesis. Professional advisement of the project and critical reviewing of the manuscript were provided by Sr. Robert J. Watters, Dr. Joseph Lints, Jr. and Dr. Y. S. Kim. Dr. Y. S. Kira graciously made the Rock Mechanics Laboratory and testing equipment available. Dr. Robert J. Watters also allowed unlimited freedom to the Geological Engineering Laboratory equipment and also, along with Dr. Joseph Lintz, Jr., provided invaluable guidance throughout the thesis preparation. Appreciation for help in de-bugging the laboratory equipment goes to my colleague, Ken Krank. Finally, and most importantly, I am indebted to my parents who, whenever I needed them, were always present and supportive. ABSTRACT Geology, physical and engineering properties of the rock units of the lousetown Basalts and Latites in the Trucked Area, California were determined by field and laboratory testing and field ODservations. Of the 16 properties that were calculated for massive samples, 8 were shown to be capable of preuicting i^-e compressive strength and 10 were shown to be capable of predicting the Elastic Modulus.
    [Show full text]
  • Hydrothermal Alteration and Mass Exchange in the Hornblende Latite Porphyry, Rico, Colorado
    Contrib Mineral Petrol (t 994) 116 : 199-215 Contributions to Mineralogy and Petrology Springer-Verlag 1994 Hydrothermal alteration and mass exchange in the hornblende latite porphyry, Rico, Colorado Peter B. Larson 1, Charles G. Cunningham 2, and Charles W. Naeser 3 1 Department of Geology, Washington State University, Pullman, WA 99164-2812, USA 2 United States Geological Survey, 959 National Center, Reston, VA 22092, USA 3 United States Geological Survey, MS 963, Denver Federal Center, Denver, CO 80225, USA Received March 29, 1992 / Accepted June 30, 1993 Abstract. The Rico paleothermal anomaly, southwestern component in the proximal facies reacted while the pri- Colorado, records the effects of a large hydrothermal mary plagioclase was still unreacted, but the ratio for system that was active at 4 Ma. This hydrothermal sys- these assemblages increased to 1.51 when the plagioclase tem produced the deep Silver Creek stockwork Mo de- entered the reaction paragenesis. Plagioclase reaction posit, which formed above the anomaly's heat source, during distal propylitic alteration resulted in pseudo- and shallower base and precious-metal vein and replace- morphic albite mixed with illite and a loss of NazO. ment deposits. A 65 Ma hornblende latite porphyry is CaO is lost in the distal facies as hornblende reacts to present as widespread sills throughout the area and pro- chlorite, although some calcium may be fixed in calcite. vided a homogeneous material that recorded the effects CaO is added to the proximal facies as the quantity of the hydrothermal system up to 8 km from the center. of chlorite replacing hornblende increases and epidote Hydrothermal alteration in the latite can be divided into and calcite are produced.
    [Show full text]
  • Description of Map Units
    GEOLOGIC MAP OF THE LATIR VOLCANIC FIELD AND ADJACENT AREAS, NORTHERN NEW MEXICO By Peter W. Lipman and John C. Reed, Jr. 1989 DESCRIPTION OF MAP UNITS [Ages for Tertiary igneous rocks are based on potassium-argon (K-Ar) and fission-track (F-T) determinations by H. H. Mehnert and C. W. Naeser (Lipman and others, 1986), except where otherwise noted. Dates on Proterozoic igneous rocks are uranium-lead (U-Pb) determinations on zircon by S. A. Bowring (Bowring and others, 1984, and oral commun., 1985). Volcanic and plutonic rock names are in accord with the IUGS classification system, except that a few volcanic names (such as quartz latite) are used as defined by Lipman (1975) following historic regional usage. The Tertiary igneous rocks, other than the peralkaline rhyolites associated with the Questa caldera, constitute a high-K subalkaline suite similar to those of other Tertiary volcanic fields in the southern Rocky Mountains, but the modifiers called for by some classification schemes have been dropped for brevity: thus, a unit is called andesite, rather than alkali andesite or high-K andesite. Because many units were mapped on the basis of compositional affinities, map symbols were selected to emphasize composition more than geographic identifier: thus, all andesite symbols start with Ta; all quartz latites with Tq, and so forth.] SURFICIAL DEPOSITS ds Mine dumps (Holocene)—In and adjacent to the inactive open pit operation of Union Molycorp. Consist of angular blocks and finer debris, mainly from the Sulphur Gulch pluton Qal Alluvium (Holocene)—Silt, sand, gravel, and peaty material in valley bottoms.
    [Show full text]
  • Petrography Edward F
    Chapter 4 Petrography Edward F. Stoddard A petrographic study was taken in order to help determine the sources of lithic artifacts found at archaeological sites on Fort Bragg. In the first phase of the study, known and suspected archaeological quarry sites in the central Piedmont of North Carolina were visited. From each quarry, hand specimens were collected and petrographic thin sections were examined in an attempt to establish a basis for distinguishing among the quarries. If material from each quarry was sufficiently distinctive, then quarry sources could potentially be matched with Fort Bragg lithic artifacts. Seventy-one samples from 12 quarry zones were examined (Table 4.1). Thirty- one of these samples are from five quarry zones in the Uwharrie Mountains region; 20 of these were collected and described previously by Daniel and Butler (1996). Forty specimens were collected from seven additional quarry zones in Chatham, Durham, Person, Orange, and Cumberland Counties. All quarries are within the Carolina Terrane, except the Cumberland County quarry, which occurs in younger sedimentary material derived primarily from Carolina Terrane outcrops. Rocks include both metavolcanic and metasedimentary types. Compositionally, most metavolcanic rocks are dacitic and include flows, tuffs, breccias, and porphyries. Metasedimentary rocks are metamudstone and fine metasandstone. The Uwharrie quarries are divided into five zones: Eastern, Western, Southern, Asheboro, and Southeastern. The divisions are based primarily on macroscopic petrography and follow the results of Daniel and Butler (1996); the Uwharries Southeastern zone was added in this study. Each of the Uwharrie quarry zones represents three to six individual quarries in relatively close proximity. Rock specimens are all various felsic metavolcanic rocks, but zones may be distinguished based upon mineralogy and texture.
    [Show full text]
  • A Tale of Two Walker Lane Pull-Apart Basins in the Ancestral Cascades Arc, Central Sierra Nevada, California GEOSPHERE; V
    Research Paper THEMED ISSUE: Origin and Evolution of the Sierra Nevada and Walker Lane GEOSPHERE A tale of two Walker Lane pull-apart basins in the ancestral Cascades arc, central Sierra Nevada, California GEOSPHERE; v. 14, no. 5 Cathy J. Busby1, K. Putirka2, Benjamin Melosh3, Paul R. Renne4,5, Jeanette C. Hagan6, Megan Gambs7, and Catherine Wesoloski1 1Department of Earth and Planetary Science, University of California, Davis, California 95616, USA https://doi.org/10.1130/GES01398.1 2Department of Earth and Environmental Sciences, California State University, Fresno, California 93720, USA 3U.S. Geological Survey, Menlo Park, California 94025, USA 15 figures; 1 table; 1 set of supplemental files; 4Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, California 94709, USA 2 oversized figures 5Department of Earth and Planetary Science, University of California, Berkeley, California 94720, USA 6Exxon Mobil, Houston, Texas 77389, USA 7School of Oceanography, University of Washington, Seattle, Washington 98105, USA CORRESPONDENCE: cjbusby@ ucdavis .edu CITATION: Busby, C.J., Putirka, K., Melosh, B., Renne, P.R., Hagan, J.C., Gambs, M., and Wesoloski, ABSTRACT ter is dominated by Stanislaus Group basalt, trachybasaltic andesite, trachy- C., 2018, A tale of two Walker Lane pull-apart basins andesite, and andesite. Climactic eruptions at its southern end produced the in the ancestral Cascades arc, central Sierra Nevada, We integrate new geochronological, petrographic, and geochemical data Little Walker caldera and its Stanislaus Group trachydacite
    [Show full text]
  • Lexicon of Stratigraphic Names Used in South-Central Colorado Amd Northern New Mexico, San Luis Basin Christina Lochman-Balk and James E
    New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/22 Lexicon of stratigraphic names used in south-central Colorado amd northern New Mexico, San Luis Basin Christina Lochman-Balk and James E. Bruning, 1971, pp. 101-111 in: San Luis Basin (Colorado), James, H. L.; [ed.], New Mexico Geological Society 22nd Annual Fall Field Conference Guidebook, 340 p. This is one of many related papers that were included in the 1971 NMGS Fall Field Conference Guidebook. Annual NMGS Fall Field Conference Guidebooks Every fall since 1950, the New Mexico Geological Society (NMGS) has held an annual Fall Field Conference that explores some region of New Mexico (or surrounding states). Always well attended, these conferences provide a guidebook to participants. Besides detailed road logs, the guidebooks contain many well written, edited, and peer-reviewed geoscience papers. These books have set the national standard for geologic guidebooks and are an essential geologic reference for anyone working in or around New Mexico. Free Downloads NMGS has decided to make peer-reviewed papers from our Fall Field Conference guidebooks available for free download. Non-members will have access to guidebook papers two years after publication. Members have access to all papers. This is in keeping with our mission of promoting interest, research, and cooperation regarding geology in New Mexico. However, guidebook sales represent a significant proportion of our operating budget. Therefore, only research papers are available for download. Road logs, mini-papers, maps, stratigraphic charts, and other selected content are available only in the printed guidebooks. Copyright Information Publications of the New Mexico Geological Society, printed and electronic, are protected by the copyright laws of the United States.
    [Show full text]
  • Mafic Volcanism and Environmental Geology of the Eastern Snake River Plain 143
    Hughes and others -- Mafic Volcanism and Environmental Geology of the Eastern Snake River Plain 143 Mafic Volcanism and Environmental Geology of the Eastern Snake River Plain, Idaho Scott S. Hughes Department of Geology, Idaho State University, Pocatello, ID 83209 Richard P. Smith Idaho National Engineering and Environmental Laboratory, P.O. Box 1625, M.S. 2107, Idaho Falls, ID 83403 William R. Hackett WRH Associates, Salt Lake City, UT 84117 Steven R. Anderson U.S. Geological Survey, INEEL Project Office, Idaho Falls, ID 83403 ABSTRACT Geology presented in this field guide covers a wide spectrum especially potatoes, grains and sugar beets, is the dominant of internal and surficial processes of the eastern Snake River Plain, economy supported by a vast groundwater and surface water sys- one of the largest components of the combined late Cenozoic ig- tem. The Idaho National Engineering and Environmental Labo- neous provinces of the western United States. Focus is on Qua- ratory (INEEL), a U.S. Department of Energy nuclear facility, ternary basaltic plains volcanism that produced monogenetic coa- covers 2,315 km2 of the ESRP. Much of the remaining rangeland, lescent shields, and phreatomagmatic eruptive centers that pro- including that which is covered by relatively fresh lava flows, is duced tuff cones and rings. These dominant systems are com- controlled by the U.S. Bureau of Land Management. The terrain pared to compositionally evolved polygenetic eruptive centers is semiarid steppe developed on eolian and lacustrine soils that and silicic domes that represent an extended range of petrologic variably cover broad expanses of basaltic lava. The ESRP is processes.
    [Show full text]
  • And Correlation of the Tertiary Volcanic Rocks of the Awapa Plateau, Garfield, Piute, and Wayne Counties, Utah
    PETROLOGY, AGE, GEOCHEMISTRY, AND CORRELATION OF THE TERTIARY VOLCANIC ROCKS OF THE AWAPA PLATEAU, GARFIELD, PIUTE, AND WAYNE COUNTIES, UTAH by Stephen R. Mattox Department of Geology Northern Illinois University c:: Cl Vl MISCELLANEOUS PUBLICATION 91-5 MAY 1991 UTAH GEOLOGICAL SURVEY a division of UTAH DEPARTMENT OF NATURAL RESOURCES o STATE OF UTAH Norman H. Bangerter~ Governor DEPARTMENT OF NATURAL RESOURCES Dee C. H ansen~ Executive Director UTAH GEOLOGICAL SURVEY M. Lee Allison~ Director BOARD Member Representing Kenneth R. Poulson, Chairman .................................................... Mineral Industry Lawrence Reaveley .............................................................. Civil Engineering Jo Brandt ........................................................................ Public-at-Large Samuel C. Quigley ............................................................... Mineral Industry Russell C. Babcock, Jr. ........................................................... Mineral Industry Vacant. .. Mineral Industry Milton E. Wadsworth .................................................. Economics-Business/ Scientific Richard J. Mitchell, Director, Division of State Lands ................................ Ex officio member UGS EDITORIAL STAFF J. Stringfellow ............................................................................ Editor Patti F. MaGann, Sharon Hamre ...................................................... Editorial Staff James W. Parker, Patricia Speranza ..................................................
    [Show full text]
  • I Geology and Petrography of Volcanic Rocks of the Truk Islands, East Qqa .2 T»C Caroline Islands
    I Geology and Petrography of Volcanic Rocks of the Truk Islands, East QQa .2 t»C Caroline Islands 3 GEOLOGICAL SURVEY PROFESSIONAL PAPER 409 19 O QQ I 1 OQ Geology and Petrography of Volcanic Rocks of the Truk Islands, East Caroline Islands By J. T. STARK and R. L. HAY GEOLOGICAL SURVEY PROFESSIONAL PAPER 409 A structural, stratigraphic, and petrographic study of the rocks of a highly dissected, partly submerged inactive shield volcano UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1963 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington 25, D.C. CONTENTS Page Page Abstract- 1 16 Introduction . 1 Petrography of eastern and western islands 17 1 Olivine basalt 17 o Nepheline basalt 19 Melilite-nepheline basalt _ 20 Nepheline basanite - 20 Geology6J q Classification 20 4 9,0 Eastern islands . 5 Trachyte, ___ 21 Moen 5 22 Falo.. _-_.---.- 6 22 YanagL 6 22 Dublon Island 6 Andesite, basalt, and trachyte blocks 22 -CjTiGri 7 Gabbro blocks _ 23 Fefan. _ _ 7 25 Param _ 7 Tarik._ _ _____________ _____.-_ 8 Tsis _ - 8 OK Uman, Tako, and Atkin . __ q 25 9 Monzonite blocks- 26 q Limestone fragments 27 9 27 Chemical composition and variation diagrams _ 27 Lava flows and autoclastic breccias __ 9 29 Dikes 10 Conclusions 32 Udot__. ________________________________ 10 Eastern and western islands Eot 10 qq Eiol 11 qq 11 Trachyte and quartz trachyte. 34 11 Gabbro blocks 36 19 Recrystallized basalt blocks 38 12 Dikes of andesite and basalt in gabbro 38 12 Monzonite and quartz monzonite .
    [Show full text]
  • Geology and Mineral Resources of Dwyer Quadrangle, Grant, Luna, and Sierra Counties, New Mexico
    BULLETIN 38 Geology and Mineral Resources of Dwyer Quadrangle, Grant, Luna, and Sierra Counties, New Mexico by WOLFGANG E. ELSTON 1957 STATE BUREAU OF MINES AND MINERAL RESOURCES NEW MEXICO INSTITUTE OF MINING & TECHNOLOGY CAMPUS STATION SOCORRO, NEW MEXICO NEW MEXICO INSTITUTE OF MINING & TECHNOLOGY E. J. Workman, President STATE BUREAU OF MINES AND MINERAL RESOURCES Alvin J. Thompson, Director THE REGENTS MEMBERS Ex OFFICIO The Honorable Edwin L. Mechem....................... Governor of New Mexico Mrs. Georgia L. Lusk .........................Superintendent of Public Instruction APPOINTED MEMBERS Robert W. Botts ...................................................................... Albuquerque Holm 0. Bursum, Jr. ........................................................................ Socorro Thomas M. Cramer ........................................................................ Carlsbad John N. Mathews, Jr. ...................................................................... Socorro Richard A. Matuszeski ............................................................ Albuquerque Contents Page ABSTRACT ........................................................................................................ i INTRODUCTION ......................................................................................... 1 Purpose and scope ....................................................................................... 1 Methods of investigation ............................................................................. 1 Previous work
    [Show full text]
  • Milner and Duncan Etendeka Quartz Latites
    Communs geol. Surv. S.W. Africa/Namibia, 3, (1987) 87-95 GEOCHEMICAL CHARACTERISATION OF QUARTZ LATITE UNITS IN THE ETENDEKA FORMATION S.C. Milner and A.R. Duncan Department of Geochemistry, University of Cape Town, Rondebosch 7700 ABSTRACT Quartz latite units interbedded with basaltic lavas in the Etendeka Formation form extensive sheet-like deposits which are probably the product of high temperature ash-flows. Apart from some systematic differences between pitchstone and devitrified quartz latites, largely explained by low temperature alteration processes, individual quartz latite units exhibit remarkably uniform compositions. No significant lateral compositional variations within individual units are observed and compositional changes occur only in the uppermost parts of any particular unit. A regional stratigraphic correlation is difficult to establish due to local differences that may be attributed to palaeotopog- raphy and the faulted nature of the coastal region in the Etendeka. In this study geochemistry has been used as a primary criterion for the correlation of major quartz latite units within the southern Etendeka area. 1. INTRODUCTION bles a stratigraphic correlation of units where field and petrographic relationships are obscure. The effects of The geology of the Etendeka region in S.W.A/Na- primary within-unit variation and secondary alteration mibia has been described in some detail by Erlank et al. have also been taken into consideration. In all of the (1984) and Milner (1986). In summary, the Etendeka diagrams the data presented were not recalculated to Formation consists of a series of interbedded basalt and 100% on a volatile free basis. quartz latite units which overlie Karoo sediments and pre-Karoo basement.
    [Show full text]
  • A New Perspective on Cenozoic Calc-Alkaline and Shoshonitic Volcanic Rocks, Eastern Saveh (Central Iran)
    International Geology Review ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/tigr20 A new perspective on Cenozoic calc-alkaline and shoshonitic volcanic rocks, eastern Saveh (central Iran) Fatemeh Nouri, Hossein Azizi, Yoshihiro Asahara & Robert J. Stern To cite this article: Fatemeh Nouri, Hossein Azizi, Yoshihiro Asahara & Robert J. Stern (2021) A new perspective on Cenozoic calc-alkaline and shoshonitic volcanic rocks, eastern Saveh (central Iran), International Geology Review, 63:4, 476-503, DOI: 10.1080/00206814.2020.1718005 To link to this article: https://doi.org/10.1080/00206814.2020.1718005 Published online: 28 Jan 2020. Submit your article to this journal Article views: 127 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=tigr20 INTERNATIONAL GEOLOGY REVIEW 2021, VOL. 63, NO. 4, 476–503 https://doi.org/10.1080/00206814.2020.1718005 ARTICLE A new perspective on Cenozoic calc-alkaline and shoshonitic volcanic rocks, eastern Saveh (central Iran) Fatemeh Nouria, Hossein Azizi a, Yoshihiro Asaharab and Robert J. Sternc aDepartment of Mining Engineering, Faculty of Engineering, University of Kurdistan, Sanandaj, Iran; bDepartment of Earth and Environmental Sciences, Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan; cGeosciences Department, University of Texas at Dallas, Richardson, TX, USA ABSTRACT ARTICLE HISTORY Late Eocene – Oligocene volcanic rocks in the eastern Saveh region of the Urumieh-Dokhtar Received 7 September 2019 magmatic arc (UDMA) are representative of Paleogene magmatic activity in Iran. They show Accepted 11 January 2020 a wide range of silica-undersaturated to silica-oversaturated compositions, from basalt-trachy KEYWORDS fi basalt and tephri-phonolite to trachyte-latite.
    [Show full text]