DOCSLIB.ORG

Precambrian Metamorphism in the Placitas-Juan Tabo Area, Northwestern Sandia Mountains, New Mexico John L

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Precambrian Metamorphism in the Placitas-Juan Tabo Area, Northwestern Sandia Mountains, New Mexico John L New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/30 Precambrian metamorphism in the Placitas-Juan Tabo area, northwestern Sandia Mountains, New Mexico John L. Berkeley and J. F. Callender, 1979, pp. 181-188 in: Santa Fe Country, Ingersoll, R. V. ; Woodward, L. A.; James, H. L.; [eds.], New Mexico Geological Society 30th Annual Fall Field Conference Guidebook, 310 p. This is one of many related papers that were included in the 1979 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 Geol. Soc. Guidebook, 30th Field Conf., Santa Fe Country, 1979 181 PRECAMBRIAN METAMORPHISM IN THE PLACITAS-JUAN TABO AREA, NORTHWESTERN SANDIA MOUNTAINS, NEW MEXICO JOHN L. BERKLEY and JONATHAN F. CALLENDER Department of Geology University of New Mexico Albuquerque, New Mexico 87131 INTRODUCTION PRECAMBRIAN ROCKS Precambrian rocks of the northwestern Sandia Mountains Rincon Metamorphics consist of a thick metasedimentary sequence which has been intruded by plutonic rocks of "granitic" composition. Meta- Metamorphic rocks in the Placitas-Juan Tabo area consist of morphic recrystallization occurred in two major episodes, a a tightly folded sequence of pelitic phyllite, schist and gneiss, regional greenschist event and subsequent hornblende-hornfels quartzofeldspathic gneiss, calc-silicate beds and amphibolite contact metamorphism associated with regional plutonism. lenses. These units generally have a northeasterly strike and an This paper summarizes the geology of a part of this Precam- easterly dip (fig. 1). Phyllite and gneiss are more abundant in brian sequence and outlines the environment of metamorph- the north, whereas schist and schistose gneiss predominate to ism and metamorphic history of the area. The lack of modern, the south. Bulk chemistry of examples of the various rock detailed studies on Precambrian rocks of the Sandia Moun- types are given in Table 1. tains, coupled with extensive Phanerozoic cover and complex Metapelitic rocks include chlorite-muscovite phyllite, Cenozoic structures, prevented regional correlation with other muscovite-biotite schist, generally with andalusite porphyro- nearby Precambrian rocks. However, recent work by Gramb- blasts, muscovite-biotite-andalusite gneiss and biotite-sillima- ling, Robertson and Moench, and Condie (all, this guidebook), nite gneiss. Quartzofeldspathic rocks are mainly microcline Condie and Budding (1979), Callender and others (1976), gneiss, thinly bedded metagraywacke and rare, discontinuous among others, suggests that the Precambrian events described quartzite. Pebble conglomerate and relict cross-bedding are here may be related to a broad zone of regional metamorph- found locally in quartzite beds. Calc-silicate rocks, mainly ism, volcanism and plutonism about 1500 million years old. diopside-calcite-quartz (± grossularite ± hornblende) granulite, are interbedded with pelitic and quartzofeldspathic rocks in Previous Work the northern part of the area. Thinly bedded, quartz-rich The region was mapped first in reconnaissance fashion by amphibolite is intercalated with the calc-silicate rocks. Thinly Hayes (1951), who mainly focused on rocks of the Juan Tabo laminated chlorite schist, greenstone and amphibolite layers, basin about 5 km south of the Placitas-Juan Tabo area. Fitz- generally containing less modal quartz than mafic layers in simmons (1961) and Kelley and Northrop (1975) summarized calc-silicate beds, are exposed locally throughout the Rincon the Precambrian geology of the Sandia Mountains. Kelley and metamorphics. Chlorite schist, and amphibolite layers and Northrop (1975) suggested the name Rincon metamorphics lenses crop out in schist and gneiss, whereas greenstone gener- for metamorphic rocks of the northwestern Sandia Mountains. ally is restricted to small boudinaged pods in phyllite. This terminology is used here. Green and Callender (1973) Field relations and bulk chemistry of the Rincon meta- delineated the geometry of the hornblende-hornfels contact morphics suggest that they represent a metamorphosed se- metamorphic aureole; Berkley and others (1976) outlined the quence of predominantly clastic sedimentary rocks. Foliation, metamorphic history of the area. bedding and lithologic contacts are generally parallel through- out the area, although subsequent thermal effects have altered Geologic Setting this relationship near the Sandia granite. Relict cross-bedding, The location and general geology of the Placitas-Juan Tabo metaconglomerate lenses, interfingering lithologic contacts and area are shown in Figure 1. The western face of the Sandia remnant clastic texture in metagraywacke and quartzite imply Mountains forms the eastern margin of the Albuquerque basin sedimentary protoliths for the schist and gneiss units. Calc- of the Rio Grande rift (Kelley, 1977; Woodward and others, silicate rocks probably represent siliceous limestones or dolo- 1975). Precambrian rocks are exposed along the northwestern mites; the discontinuous nature of many of these beds may foothills of the Sandia Mountains, mainly in a prominent reflect changes in stratigraphic thickness along strike. Quartz- northeasterly trending spur, Rincon Ridge. Rincon Ridge is bearing amphibolites intercalated with calc-silicate rocks com- bounded on the west by the Rincon fault, which marks the monly contain alternating laminae of aluminous silicate and eastern edge of the rift (Kelley and Northrop, 1975), and on calcareous assemblages. These amphibolites may have formed the east locally by an eastward-dipping normal fault, the from a reaction of pelitic and calcareous material in inter- Piedra Lisa fault, which offsets Precambrian rocks in the south- layered calcareous shales or mudstones (Orville, 1969). More western part of the area (fig. 1). Other normal faults, mainly mafic chlorite schist, greenstone and amphibolite lithologies, Tertiary in age, have deformed the northern part of the area; which are generally conformable to regional bedding, may rep- the more important faults are shown in Figure 1. The Rincon resent metamorphosed mafic tuffs, flows or sills. Estimates of metamorphics are overlain by Phanerozoic sediments to the stratigraphic thickness are complicated by folding and young north and bordered by Precambrian plutonic rocks on the faulting, but range from 1000 m to over 2000 m (Hayes, 1951). south and east. Sandia Granite ing to Taggart and Brookins (1975), the Sandia granite is The Sandia "granite" pluton borders the Placitas-Juan Tabo 1,504 ± 15 m.y. old. area to the east and is in intrusive contact with Rincon meta- The intrusive nature of the Sandia granite has been ques- morphics except along faults. In the Placitas-Juan Tabo area, tioned (Fitzsimmons, 1961), and indeed, the contact is grada- the "granite" commonly contains abundant plagioclase and tional in some parts of the Sandia Mountains, especially in probably is better termed quartz monzonite. Local usage, how- Tijeras Canyon, southeast of the present study area. In the ever, has thoroughly established the term "granite" for this Placitas-Juan Tabo area, however, the contact is generally in- body (Kelley and Northrop, 1975), and therefore, Sandia gran- trusive, as suggested by the following observations: (1) the ite will be used in this paper. Although consisting of several granite injects country rock as dikes and sills, some of which separate intrusive phases with distinct textures, the Sandia show dilation effects; (2) contacts are invariably sharp, al- granite is generally coarse-grained and contains large pink or though metasomatic contamination of country rock is locally gray microcline phenocrysts in
Load more

Recommended publications
  • Facies and Mafic
    Metamorphic Facies and Metamorphosed Mafic Rocks l V.M. Goldschmidt (1911, 1912a), contact Metamorphic Facies and metamorphosed pelitic, calcareous, and Metamorphosed Mafic Rocks psammitic hornfelses in the Oslo region l Relatively simple mineral assemblages Reading: Winter Chapter 25. (< 6 major minerals) in the inner zones of the aureoles around granitoid intrusives l Equilibrium mineral assemblage related to Xbulk Metamorphic Facies Metamorphic Facies l Pentii Eskola (1914, 1915) Orijärvi, S. l Certain mineral pairs (e.g. anorthite + hypersthene) Finland were consistently present in rocks of appropriate l Rocks with K-feldspar + cordierite at Oslo composition, whereas the compositionally contained the compositionally equivalent pair equivalent pair (diopside + andalusite) was not biotite + muscovite at Orijärvi l If two alternative assemblages are X-equivalent, l Eskola: difference must reflect differing we must be able to relate them by a reaction physical conditions l In this case the reaction is simple: l Finnish rocks (more hydrous and lower MgSiO3 + CaAl2Si2O8 = CaMgSi2O6 + Al2SiO5 volume assemblage) equilibrated at lower En An Di Als temperatures and higher pressures than the Norwegian ones Metamorphic Facies Metamorphic Facies Oslo: Ksp + Cord l Eskola (1915) developed the concept of Orijärvi: Bi + Mu metamorphic facies: Reaction: “In any rock or metamorphic formation which has 2 KMg3AlSi 3O10(OH)2 + 6 KAl2AlSi 3O10(OH)2 + 15 SiO2 arrived at a chemical equilibrium through Bt Ms Qtz metamorphism at constant temperature and =
    [Show full text]
  • Briefguiderocks Copy
    BRIEF GUIDE TO ROCKS What is a rock? • A mixture of minerals. • A naturally occurring solid. • A “time machine” with a story to tell. All rocks tell a story; a rock represents a period of time (during which it was formed), an environment (in which it was formed) and a geologic process (how it was formed). By “reading the record of a rock” you can understand its history. Sandia Granite How are rocks classified? • Igneous: solidified from magma (molten, or liquid, rock within the Earth) Note: Igneous rocks are further divided into Plutonic (the magma solidified beneath Earth’s surface) and Volcanic (the magma erupted onto Earth’s surface to become lava and the lava solidified at the surface). Examples: Plutonic = granite, gabbro, granodiorite, monzonite Volcanic = basalt, rhyolite, pumice, obsidian • Sedimentary: rocks produced by the movement and deposition of eroded minerals, sand, silt, pebbles, or cobbles or by the deposition of precipitates. Note: Sedimentary rocks are divided into Clastic (a rock with layers of sediment of various grain sizes) or Chemical (a rock formed by precipitation of chemicals layer by layer out of water). Examples: Clastic = sandstone, shale Chemical = limestone, travertine • Metamorphic: a pre-existing rock (igneous or sedimentary or even metamorphic) that has been altered by changes in temperature, pressure, or stress into a different type of rock by mineralogical, chemical, and/or structural changes, while in the solid state. Note: Metamorphic rocks are sometimes classified by geologists into levels of metamorphism (how much it has changed) from low to high intensity. Metamorphic rocks that have been under pressure show an alignment of minerals that is called foliation.
    [Show full text]
  • Finding of Prehnite-Pumpellyite Facies Metabasites from the Kurosegawa Belt in Yatsushiro Area, Kyushu, Japan
    Journal ofPrehnite Mineralogical-pumpellyite and Petrological facies metabasites Sciences, in Yatsushiro Volume 107, area, page Kyushu 99─ 104, 2012 99 LETTER Finding of prehnite-pumpellyite facies metabasites from the Kurosegawa belt in Yatsushiro area, Kyushu, Japan * * ** Kenichiro KAMIMURA , Takao HIRAJIMA and Yoshiyuki FUJIMOTO *Department of Geology and Mineralogy, Graduate School of Science, Kyoto University, Kitashirakawa Oiwakecho, Kyoto 606-8502, Japan ** Nittetsu-Kogyo Co., Ltd, 2-3-2 Marunouchi, Chiyoda, Tokyo 100-8377, Japan. Common occurrence of prehnite and pumpellyite is newly identified from metabasites of Tobiishi sub-unit in the Kurosegawa belt, Yatsushiro area, Kyushu, where Ueta (1961) had mapped as a greenschist facies area. Prehnite and pumpellyite are closely associated with chlorite, calcite and quartz, and they mainly occur in white colored veins or in amygdules in metabasites of the relevant area, but actinolite and epidote are rare in them. Pumpellyite is characterized by iron-rich composition (7.2-20.0 wt% as total iron as FeO) and its range almost overlaps with those in prehnite-pumpellyite facies metabasites of Ishizuka (1991). These facts suggest that the metabasites of the Tobiishi sub-unit suffered the prehnite-pumpellyite facies metamorphism, instead of the greenschist facies. Keywords: Prehnite-pumpellyite facies, Lawsonite-blueschist facies, Kurosegawa belt INTRODUCTION 1961; Kato et al., 1984; Maruyama et al., 1984; Tsujimori and Itaya, 1999; Tomiyoshi and Takasu, 2009). Until now, The subduction zone has an essential role for the global there is neither clear geological nor petrological evidence circulation of solid, fluid and volatile materials between suggesting what type of metamorphic rocks occupied the the surface and inside of the Earth at present.
    [Show full text]
  • Oregon Geologic Digital Compilation Rules for Lithology Merge Information Entry
    State of Oregon Department of Geology and Mineral Industries Vicki S. McConnell, State Geologist OREGON GEOLOGIC DIGITAL COMPILATION RULES FOR LITHOLOGY MERGE INFORMATION ENTRY G E O L O G Y F A N O D T N M I E N M E T R R A A L P I E N D D U N S O T G R E I R E S O 1937 2006 Revisions: Feburary 2, 2005 January 1, 2006 NOTICE The Oregon Department of Geology and Mineral Industries is publishing this paper because the infor- mation furthers the mission of the Department. To facilitate timely distribution of the information, this report is published as received from the authors and has not been edited to our usual standards. Oregon Department of Geology and Mineral Industries Oregon Geologic Digital Compilation Published in conformance with ORS 516.030 For copies of this publication or other information about Oregon’s geology and natural resources, contact: Nature of the Northwest Information Center 800 NE Oregon Street #5 Portland, Oregon 97232 (971) 673-1555 http://www.naturenw.org Oregon Department of Geology and Mineral Industries - Oregon Geologic Digital Compilation i RULES FOR LITHOLOGY MERGE INFORMATION ENTRY The lithology merge unit contains 5 parts, separated by periods: Major characteristic.Lithology.Layering.Crystals/Grains.Engineering Lithology Merge Unit label (Lith_Mrg_U field in GIS polygon file): major_characteristic.LITHOLOGY.Layering.Crystals/Grains.Engineering major characteristic - lower case, places the unit into a general category .LITHOLOGY - in upper case, generally the compositional/common chemical lithologic name(s)
    [Show full text]
  • A Systematic Nomenclature for Metamorphic Rocks
    A systematic nomenclature for metamorphic rocks: 1. HOW TO NAME A METAMORPHIC ROCK Recommendations by the IUGS Subcommission on the Systematics of Metamorphic Rocks: Web version 1/4/04. Rolf Schmid1, Douglas Fettes2, Ben Harte3, Eleutheria Davis4, Jacqueline Desmons5, Hans- Joachim Meyer-Marsilius† and Jaakko Siivola6 1 Institut für Mineralogie und Petrographie, ETH-Centre, CH-8092, Zürich, Switzerland, [email protected] 2 British Geological Survey, Murchison House, West Mains Road, Edinburgh, United Kingdom, [email protected] 3 Grant Institute of Geology, Edinburgh, United Kingdom, [email protected] 4 Patission 339A, 11144 Athens, Greece 5 3, rue de Houdemont 54500, Vandoeuvre-lès-Nancy, France, [email protected] 6 Tasakalliontie 12c, 02760 Espoo, Finland ABSTRACT The usage of some common terms in metamorphic petrology has developed differently in different countries and a range of specialised rock names have been applied locally. The Subcommission on the Systematics of Metamorphic Rocks (SCMR) aims to provide systematic schemes for terminology and rock definitions that are widely acceptable and suitable for international use. This first paper explains the basic classification scheme for common metamorphic rocks proposed by the SCMR, and lays out the general principles which were used by the SCMR when defining terms for metamorphic rocks, their features, conditions of formation and processes. Subsequent papers discuss and present more detailed terminology for particular metamorphic rock groups and processes. The SCMR recognises the very wide usage of some rock names (for example, amphibolite, marble, hornfels) and the existence of many name sets related to specific types of metamorphism (for example, high P/T rocks, migmatites, impactites).
    [Show full text]
  • Proterozoic Magmatism and Regional Contact Metamorphism in the Sandia-Manzano Mountains, New Mexico, USA Tyler A
    New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/67 Proterozoic magmatism and regional contact metamorphism in the Sandia-Manzano Mountains, New Mexico, USA Tyler A. Grambling, Karl E. Karlstrom, Mark E. Holland, and Nadine L. Grambling, 2016, pp. 169-175 in: Guidebook 67 - Geology of the Belen Area, Frey, Bonnie A.; Karlstrom, Karl E. ; Lucas, Spencer G.; Williams, Shannon; Ziegler, Kate; McLemore, Virginia; Ulmer-Scholle, Dana S., New Mexico Geological Society 67th Annual Fall Field Conference Guidebook, 512 p. This is one of many related papers that were included in the 2016 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.
    [Show full text]
  • The Greenschist to Amphibolite Facies Tonalite-Greenstone Terrain of The
    95 THE PIKWITONEI GRANULITE DOMAIN: A LOWER CRUSTAL LEVEL ALONG THE CHURCHILL-SUPERIOR BOUNDARY IN CENTRAL MANITOBA. W. Weber, Manitoba Geological Services Branch, Winnipeg, Manitoba, Canada, R3H OW4 The greenschist to amphibolite facies tonalite-greenstone terrain of the Gods Lake subprovince grades - in a northwesterly direction - into the granulite facies Pikwitonei domain (1) at the western margins of the Superior Province,. The transition is the result of prograde metamorphism and takes place over 50 - 100 km without any structural or lithological breaks. Locally the orthopyroxene isograd is oblique to the structural grain and transects greenstone belts, e.g., the Cross Lake belt (2). The greenstone belts in the granulite facies and adjacent lower grade domain consist mainly of mafic and (minor) ultramafic metavolcanics, and clastic and chemical metasedimentary rocks (1,2). Typical for the greenstone belts crossed by the orthopyroxene isograd are anorthositic gabbros and anorthosites, and plagiophyric mafic flows. Available data suggest a late Aphebian age for the prograde greenschist to granulite facies metamorphism. Peak conditions are reflected by saphirin-bearing and opx-sillimanite quartz gneisses which indicate 10 - 11 kb pressure and temperatures of 900 - 1000°C (2). At its western and northern edge - towards the contact with the Churchill Province - the rocks of the Pikwitonei granulite domain were overprinted by the Hudsonian orogeny; they were deformed, selectively retrogressed and recrystallized under greenschist to amphibolite facies conditions (1,2); locally they were migmatized. The Thompson belt, the Split Lake block and a linear zone south of the Fox River consists of these reworked granulites. Proterozoic rocks of the Circum-Superior belt (3) (apparently) overlie the reworked granulites along the Fox River and in the Thompson belt.
    [Show full text]
  • Metamorphic Rocks
    Metamorphic Rocks Geology 200 Geology for Environmental Scientists Regionally metamorphosed rocks shot through with migmatite dikes. Black Canyon of the Gunnison, Colorado Metamorphic rocks from Greenland, 3.8 Ga (billion years old) Major Concepts • Metamorphic rocks can be formed from any rock type: igneous, sedimentary, or existing metamorphic rocks. • Involves recrystallization in the solid state, often with little change in overall chemical composition. • Driving forces are changes in temperature, pressure, and pore fluids. • New minerals and new textures are formed. Major Concepts • During metamorphism platy minerals grow in the direction of least stress producing foliation. • Rocks with only one, non-platy, mineral produce nonfoliated rocks such as quartzite or marble. • Two types of metamorphism: contact and regional. Metamorphism of a Granite to a Gneiss Asbestos, a metamorphic amphibole mineral. The fibrous crystals grow parallel to least stress. Two major types of metamorphism -- contact and regional Major Concepts • Foliated rocks - slate, phyllite, schist, gneiss, mylonite • Non-foliated rocks - quartzite, marble, hornfels, greenstone, granulite • Mineral zones are used to recognize metamorphic facies produced by systematic pressure and temperature changes. Origin of Metamorphic Rocks • Below 200oC rocks remain unchanged. • As temperature rises, crystal lattices are broken down and reformed with different combinations of atoms. New minerals are formed. • The mineral composition of a rock provides a key to the temperature of formation (Fig. 6.5) Fig. 6.5. Different minerals of the same composition, Al2SiO5, are stable at different temperatures and pressures. Where does the heat come from? • Hot magma ranges from 700-12000C. Causes contact metamorphism. • Deep burial - temperature increases 15-300C for every kilometer of depth in the crust.
    [Show full text]
  • Stratigraphy of Ontario Ridge Metasediments
    Pseudo-stratigraphic Column of Ontario Ridge Metasediments Member 10: Upper portion leucocratic migmatite with minor melanocratic gneiss and locally containing small pods of hornblende rock derived from marble; melanocratic gneiss in lower portion; large swath of marble in lower portion with basal calc-silicate and calc-silicate east of Bighorn Peak, sparse quartzite outcrops. Also includes quartzite layer near Shortcut Ridge with several feet of biotite-hornblende-quartz gneiss near center. *Migmatite: light gray, medium to ne-grained; vague irregular compositional layering, layers locally intrude one another; ptygmatically folded; thin irregular aplite bodies common; average composition about 55% feldspar, 35% quartz and 10% hornblende; biotite locally present; scattered euhedra of sphene usually visible in hand specimen. *Melanocratic gneiss: conspicuously banded with dark gray layers a fraction of an inch to several inches thick alternating with whitish gray layers mostly less 10 than two inches thick; layers irregularly to semiregularly folded with wavelengths of a few inches; fold axes subparallel; dark layers ne-grained, foliated, compositionally variable but typically about 60% hornblende and/or biotite, 30% plagioclase and 10% quartz; light layers ne- to medium-grained; aplitic in appearance, lenticular with irregular shapes, composed of quartz and feldspar. *Quartzite: light gray, granoblastic, ne- to medium-grained; very thin poorly-dened bedding; tightly folded in most outcrops with fold amplitudes of a few inches to a few feet, sheared folds locally simulate crossbedding; average quartz content about 80%, biotite most common accessory. 210 meter thickness Member 9: Gneisses and migmatites dominant; migmatite extensively developed along south side of Icehouse Canyon; roughly 50 feet of dolomite marble and minor calc-silicate rocks 250 feet below top of member; minor marble and calc-silicate rocks interbedded near base; graphite-rich schists locally present.
    [Show full text]
  • Compiled by F. Allan Hills and KA Sargent This Map Report Is One of a Series of Geologic and Hydro
    DEPARTMENT OF THE INTERIOR TO ACCOMPANY UNITED STATES GEOLOGICAL SURVEY WRI REPORT 83-4118-D MAP SHOWING OUTCROPS OF GRANITIC ROCKS AND SILICIC SHALLOW-INTRUSIVE ROCKS, BASIN AND RANGE PROVINCE, NEW MEXICO Compiled by F. Allan Hills and K. A. Sargent INTRODUCTION This map report is one of a series of geologic and hydro- logic maps covering all or parts of the States within the Basin and Range province of the western United States. The map reports contain information on subjects that characterize the geohy- drology of the province, including the ground-water hydrology, ground-water quality, surface distribution of selected rock types, tectonic conditions, areal geophysics, Pleistocene lakes and marshes, and mineral and energy resources. This work is part of the U.S. Geological Survey's program for geologic and hydro- logic evalutaion of the Basin and Range province to identify potentially suitable regions for further study relative to storage of high-level nuclear waste (Bedinger, Sargent, and Reed, 1984). This map report on the granitic rocks and silicic shallow- intrusive rocks of New Mexico was prepared from published geo­ logic maps and reports utilizing the project guidelines of Sargent and Bedinger (1984). The map shows outcrops of mostly plutonic granitic rocks, but also of fine-grained and partly glassy, silicic, shallow-intrusive rocks. The outcrops have been grouped into numbered county areas, which are outlined on the map. The Description of Map Units includes the geologic, and if available, radiometric ages, the lithology, thickness where available, and sources of data. Because the classification of plutonic igneous rocks has changed since publication of many reports used in this study, the rock terminology in the original reports has been converted, where possible, to that adopted by the International Union of Geologic Sciences (IUGS), as reported by Streckeisen (1976).
    [Show full text]
  • Multiple Veining in a Paleo–Accretionary Wedge: the Metamorphic Rock Record of Prograde Dehydration and Transient High Pore- GEOSPHERE, V
    Research Paper THEMED ISSUE: Subduction Top to Bottom 2 GEOSPHERE Multiple veining in a paleo–accretionary wedge: The metamorphic rock record of prograde dehydration and transient high pore- GEOSPHERE, v. 16, no. 3 fluid pressures along the subduction interface (Western Series, https://doi.org/10.1130/GES02227.1 11 figures; 2 tables; 1 set of supplemental files central Chile) Jesús Muñoz-Montecinos1,2,*, Samuel Angiboust1,*, Aitor Cambeses3,*, and Antonio García-Casco2,4,* CORRESPONDENCE: 1 [email protected] Institut de Physique du Globe de Paris, Université de Paris, CNRS, F-75005 Paris, France 2Department of Mineralogy and Petrology, Faculty of Sciences, University of Granada, Campus Fuentenueva s/n, 18002 Granada, Spain 3Institut für Geologie, Mineralogie und Geophysik, Ruhr-Universität Bochum, Bochum 44801, Germany CITATION: Muñoz-Montecinos, J., Angiboust, S., 4Instituto Andaluz de Ciencias de la Tierra, CSIC–Universidad de Granada, Armilla, Granada 18100, Spain Cambeses, A., and García-Casco, A., 2020, Multiple veining in a paleo–accretionary wedge: The metamor- phic rock record of prograde dehydration and transient high pore-fluid pressures along the subduction inter- ABSTRACT that the formation of interlayered blueschist and fluid-rock interaction events (Zack and John, 2007). face (Western Series, central Chile): Geosphere, v. 16, greenschist layers in Pichilemu metavolcanics is a Textures recorded in veins yield information on no. 3, p. 765–786, https://doi.org/10.1130/GES02227.1. High pressure–low temperature metamorphic consequence of local bulk composition variations, crack aperture as well as crystal growth kinetics rocks from the late Paleozoic accretionary wedge and that greenschists are generally not formed due during each veining event (Cox and Etheridge, 1983; Science Editor: Shanaka de Silva exposed in central Chile (Pichilemu region) are to selective exhumation-related retrogression of Bons, 2001), while vein-filling mineral assemblages Guest Associate Editor: Gray E.
    [Show full text]
  • Geologic Map of Washington - Northwest Quadrant
    GEOLOGIC MAP OF WASHINGTON - NORTHWEST QUADRANT by JOE D. DRAGOVICH, ROBERT L. LOGAN, HENRY W. SCHASSE, TIMOTHY J. WALSH, WILLIAM S. LINGLEY, JR., DAVID K . NORMAN, WENDY J. GERSTEL, THOMAS J. LAPEN, J. ERIC SCHUSTER, AND KAREN D. MEYERS WASHINGTON DIVISION Of GEOLOGY AND EARTH RESOURCES GEOLOGIC MAP GM-50 2002 •• WASHINGTON STATE DEPARTMENTOF 4 r Natural Resources Doug Sutherland· Commissioner of Pubhc Lands Division ol Geology and Earth Resources Ron Telssera, Slate Geologist WASHINGTON DIVISION OF GEOLOGY AND EARTH RESOURCES Ron Teissere, State Geologist David K. Norman, Assistant State Geologist GEOLOGIC MAP OF WASHINGTON­ NORTHWEST QUADRANT by Joe D. Dragovich, Robert L. Logan, Henry W. Schasse, Timothy J. Walsh, William S. Lingley, Jr., David K. Norman, Wendy J. Gerstel, Thomas J. Lapen, J. Eric Schuster, and Karen D. Meyers This publication is dedicated to Rowland W. Tabor, U.S. Geological Survey, retired, in recognition and appreciation of his fundamental contributions to geologic mapping and geologic understanding in the Cascade Range and Olympic Mountains. WASHINGTON DIVISION OF GEOLOGY AND EARTH RESOURCES GEOLOGIC MAP GM-50 2002 Envelope photo: View to the northeast from Hurricane Ridge in the Olympic Mountains across the eastern Strait of Juan de Fuca to the northern Cascade Range. The Dungeness River lowland, capped by late Pleistocene glacial sedi­ ments, is in the center foreground. Holocene Dungeness Spit is in the lower left foreground. Fidalgo Island and Mount Erie, composed of Jurassic intrusive and Jurassic to Cretaceous sedimentary rocks of the Fidalgo Complex, are visible as the first high point of land directly across the strait from Dungeness Spit.
    [Show full text]