DOCSLIB.ORG

Petrology of the Sedimentary and Igneous Rocks from the Strathmore District (Sheet 57), Scotland

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Petrology of the sedimentary and igneous rocks from the Strathmore district (Sheet 57), Scotland Integrated Geological Survey (North) Internal Report IR/04/125 BRITISH GEOLOGICAL SURVEY INTERNAL REPORT IR/04/125 Petrology of the sedimentary and igneous rocks from the Strathmore district (Sheet 57), Scotland Emrys Phillips The National Grid and other Ordnance Survey data are used with the permission of the Controller of Her Majesty’s Stationery Office. Ordnance Survey licence number GD 272191/2004 Key words Petrology, sedimentary and igneous rocks, Strathmore, Scotland Bibliographical reference PHILLIPS, E. R. 2004. Petrology of the sedimentary and igneous rocks from the Strathmore district (Sheet 57), Scotland. British Geological Survey Internal Report, IR/04/125. 21pp. © NERC 2004 Keyworth, Nottingham British Geological Survey 2001 BRITISH GEOLOGICAL SURVEY The full range of Survey publications is available from the BGS Keyworth, Nottingham NG12 5GG Sales Desks at Nottingham and Edinburgh; see contact details 0115-936 3241 Fax 0115-936 3488 below or shop online at www.thebgs.co.uk e-mail: [email protected] The London Information Office maintains a reference collection www.bgs.ac.uk of BGS publications including maps for consultation. Shop online at: www.thebgs.co.uk The Survey publishes an annual catalogue of its maps and other publications; this catalogue is available from any of the BGS Sales Murchison House, West Mains Road, Edinburgh EH9 3LA Desks. 0131-667 1000 Fax 0131-668 2683 The British Geological Survey carries out the geological survey of e-mail: [email protected] Great Britain and Northern Ireland (the latter as an agency service for the government of Northern Ireland), and of the London Information Office at the Natural History Museum surrounding continental shelf, as well as its basic research (Earth Galleries), Exhibition Road, South Kensington, London projects. It also undertakes programmes of British technical aid in SW7 2DE geology in developing countries as arranged by the Department for International Development and other agencies. 020-7589 4090 Fax 020-7584 8270 020-7942 5344/45 email: [email protected] The British Geological Survey is a component body of the Natural Environment Research Council. Forde House, Park Five Business Centre, Harrier Way, Sowton, Exeter, Devon EX2 7HU 01392-445271 Fax 01392-445371 Geological Survey of Northern Ireland, 20 College Gardens, Belfast BT9 6BS 028-9066 6595 Fax 028-9066 2835 Maclean Building, Crowmarsh Gifford, Wallingford, Oxfordshire OX10 8BB 01491-838800 Fax 01491-692345 Parent Body Natural Environment Research Council, Polaris House, North Star Avenue, Swindon, Wiltshire SN2 1EU 01793-411500 Fax 01793-411501 www.nerc.ac.uk IR/04/125; Draft 0.1 Last modified: 2004/07/15 10:47 Foreword This report is the published product of a study by the British Geological Survey (BGS) on the regional geology of the Midland Valley of Scotland. It is part of the Science Budget funded programme which forms part of the core programme of BGS. This core programme is designed to undertake a multidisciplinary geological survey to meet user and strategic needs for geological information. Contents Foreword.........................................................................................................................................i Contents...........................................................................................................................................i Summary........................................................................................................................................ii 1 Introduction............................................................................................................................ 3 2 Petrology ................................................................................................................................. 3 2.1 Montrose Volcanic Formation........................................................................................ 3 2.1.1 Olivine-clinopyroxene phyric basalt ...........................................................................3 2.1.2 Medium- to coarse-grained basalt and basaltic andesite.............................................4 2.1.3 Olivine microgabbro ...................................................................................................4 2.1.4 Andesite and basaltic andesite.....................................................................................5 2.1.5 Pilotaxitic basaltic and andesitic rocks........................................................................6 2.1.6 Carbonate replaced basaltic or andesitic rock.............................................................6 2.1.7 Highly altered andesitic or microdioritic rock ............................................................6 2.1.8 Volcaniclastic or pyroclastic rocks .............................................................................6 2.1.9 Ophimottled basalt......................................................................................................7 2.2 Catterline Conglomerate Formation ............................................................................... 7 2.2.1 Matrix-rich wacke sandstone......................................................................................7 2.2.2 Quartzose litharenite...................................................................................................8 2.2.3 Volcaniclastic microconglomerate..............................................................................8 2.3 Auchmithie Conglomerate Member ............................................................................... 9 2.3.1 Sandstone ....................................................................................................................9 2.3.2 Clasts within the conglomerates..................................................................................9 2.4 Trappean Conglomerate, Scone Sandstone Formation................................................... 9 2.5 Cromlix Mudstone Formation ...................................................................................... 10 2.6 Teith Sandstone Formation........................................................................................... 10 i IR/04/125; Draft 0.1 Last modified: 2004/07/15 10:47 2.7 Glenvale Sandstone Formation..................................................................................... 11 2.8 Scone Sandstone Formation ......................................................................................... 11 2.9 Pittendriech Limestone................................................................................................. 12 2.10 Dundee Flags Formation............................................................................................... 12 2.10.1 Quartzose litharenites.............................................................................................12 2.10.2 Siltstones................................................................................................................13 2.10.3 Pebbly sandstone or microconglomerate ...............................................................13 3 Plate captions........................................................................................................................ 13 Glossary........................................................................................................................................ 14 Summary This report describes the mineralogy and petrology of a suite of basaltic to andesitic volcanic rocks and sedimentary rocks as part of the regional mapping of the Strathmore district (Sheet 57). ii IR/04/125; Draft 0.1 Last modified: 2004/07/15 10:47 1 Introduction This report describes the mineralogy and petrology of a suite of basaltic to andesitic volcanic rocks and sandstones, microconglomerates and associated sedimentary rocks of the Strathmore district (sheet 57). A total of 108 thin sections have been examined with the work forming part of a multidisciplinary project being undertaken by the British Geological Survey to examine the evolution of the Midland Valley of Scotland. This work forms part of the British Geological Survey’s Integrated Geological Survey (North) programme. 2 Petrology 2.1 MONTROSE VOLCANIC FORMATION 2.1.1 Olivine-clinopyroxene phyric basalt In thin section these basalts are typically fine-grained, anhedral granular, holocrystalline to hypocrystalline, micro- to macroporphyritic rocks (S335; S3787; S54048; S54049; S54046; S54045; S54053; S54056; S54104; S54108; S53566; S57011; S37081; S22139; S54109; S3780). They comprise an inequigranular mineral assemblage dominated by plagioclase, clinopyroxene and olivine (Plate 1) with minor to accessory opaque minerals and apatite. Phenocrysts within the basalts range up to 3.5 mm in size (typically ≤ 2.0 mm in size) and are composed of olivine (Plate 1a and b) and clinopyroxene with variable amounts of plagioclase (Plate 1c and d). These phenocrysts may exhibit a preferred shape alignment parallel to a pilotaxitic fabric locally developed within the groundmass. Olivine forms small anhedral to subhedral microphenocrysts that are variably altered to, or pseudomorphed by mesh textured chlorite, serpentine, bowlingite and iddingsite (Plate 1a and b). The pseudomorphs after olivine are typically enclosed within a rim of opaque oxides, with thin veinlets of opaque minerals also preserving fractures within the pre-existing relict olivine. These pseudomorphs after
Recommended publications
  • Bedrock Geology Glossary from the Roadside Geology of Minnesota, Richard W

    Bedrock Geology Glossary from the Roadside Geology of Minnesota, Richard W

    Minnesota Bedrock Geology Glossary From the Roadside Geology of Minnesota, Richard W. Ojakangas Sedimentary Rock Types in Minnesota Rocks that formed from the consolidation of loose sediment Conglomerate: A coarse-grained sedimentary rock composed of pebbles, cobbles, or boul- ders set in a fine-grained matrix of silt and sand. Dolostone: A sedimentary rock composed of the mineral dolomite, a calcium magnesium car- bonate. Graywacke: A sedimentary rock made primarily of mud and sand, often deposited by turbidi- ty currents. Iron-formation: A thinly bedded sedimentary rock containing more than 15 percent iron. Limestone: A sedimentary rock composed of calcium carbonate. Mudstone: A sedimentary rock composed of mud. Sandstone: A sedimentary rock made primarily of sand. Shale: A deposit of clay, silt, or mud solidified into more or less a solid rock. Siltstone: A sedimentary rock made primarily of sand. Igneous and Volcanic Rock Types in Minnesota Rocks that solidified from cooling of molten magma Basalt: A black or dark grey volcanic rock that consists mainly of microscopic crystals of pla- gioclase feldspar, pyroxene, and perhaps olivine. Diorite: A plutonic igneous rock intermediate in composition between granite and gabbro. Gabbro: A dark igneous rock consisting mainly of plagioclase and pyroxene in crystals large enough to see with a simple magnifier. Gabbro has the same composition as basalt but contains much larger mineral grains because it cooled at depth over a longer period of time. Granite: An igneous rock composed mostly of orthoclase feldspar and quartz in grains large enough to see without using a magnifier. Most granites also contain mica and amphibole Rhyolite: A felsic (light-colored) volcanic rock, the extrusive equivalent of granite.
  • Economic Geology Report ER79-4: Porphyritic Intrusions and Related

    Economic Geology Report ER79-4: Porphyritic Intrusions and Related

    MANITOBA CANADA DEPARTMENT OF ENERGY AND MINES MANITOBA MINERAL RESOURCES DIVISION ECONOMIC GEOLOGY REPORT ER79-4 PORPHYRITIC INTRUSIONS AND RELATED MINERALIZATION IN THE FLIN FLON VOLCANIC BELT by D.A. BALDWIN 1980 Funding for this project was provided under the cost-shared Canada-Manitoba Non-renewable Resources Evaluation Program by the Canada Department of Energy, Mines and Resources and the Manitoba Department of Mines, Resources and Environmental Management. MANITOBA DEPARTMENT OF ENERGY AND MINES HON. DONALD W. CRAIK PAUL E. JARVIS Minister Deputy Minister MINERAL RESOURCES DIVISION IAN HAUGH Executive Director ECONOMIC GEOLOGY REPORT ER79-4 PORPHYRITIC INTRUSIONS AND RELATED MINERALIZATION IN THE FLIN FLON VOLCANIC BELT by D.A. BALDWIN 1980 LEGEND I Cliff Lake Stock 5 Elbow Lake Stock 2 Whitefish Lake Porphyry 6 Fourmile Island Intrusion 3 Alberts Lake Intrusion 7 Chisel Lake Intrusion 4 Nisto Lake Intrusion 8 Wekusko Lake Intrusion ,~ -./ - -, I \." ~herridon '" , ;. <,.... ,1 if 55°00' 55°00' c, t,:) ,J -3 , I"" . c;? '" 1[' . ::t} \'''If!? ~,/J~ /j' ., ~), F lin.~ i;\))F ' I,".!0l~' ,d ' ;)/", ' ~.;'. l ;' ~" ,r~n ;t j; (I:/,1 ,r Lake ' \\ ;\~ ' ~i'/ 'lUi':;- -'i' //{ ,'/ , ,\" ,,/,1,1 pI , .h .(,1;' '\:. (IiI' ' .. '~'4_hl i / 'Y{j,'{:" 5 2.5 a 10 15 KILOMETRES J!) "'.t3 f3,F-"\ ---- :i~ f)J~c~. V 99°30' ">/)AfhapaplJskoj¥ !ZJ Porphyritic Intrusive Rocks 54°30' ! ,1 Lake .; ... 100°30' D Felsic Volcanic Rocks FIGURE 1: Distribution of porphyritic intrusive and felsic volcanic rocks in the Flin Flon volcanic belt, TABLE OF
  • Effect of Porphyritic Andesite Int Metamorphism Aureole in Sel

    Effect of Porphyritic Andesite Int Metamorphism Aureole in Sel

    E-ISSN : 2541-5794 P-ISSN :2503-216X Journal of Geoscience, Engineering, Environment, and Technology Vol 5 No 2 2020 RESEARCH ARTICLE Effect of Porphyritic Andesite Intrusion on The Formation of Contact Metamorphism Aureole in Selo Gajah Hill Clastic Limestone, Bojonegoro Regency, East Java, Indonesia Tri Winarno1,*, Jenian Marin1, Wisnu Wijaya Jati1 1Department of Geological Engineering, Diponegoro University, Indonesia Corresponding author : [email protected] Telp :+62 857-4006-6835 Received: Nov 18, 2019, Accepted: Jun 25, 2020. DOI 10.25299/jgeet.2020.5.2.4098 Abstract At Selo Gajah Hill, Jari Village, Gondang Sub-district, Bojonegoro Regency, East Java there are limestone intruded by porphyritic andesite. The intrusion produces contact metamorphisms in the wall rocks. It is very interesting to study the protolith rock, facies of metamorphism and the zonation of contact metamorphism aureole. This research uses field observation method and laboratory analysis i.e. petrographic analysis. Field observation is conducted by doing geological mapping in the Bukit Selo Gajah area and rock sampling for petrographic analysis. Petrographic analysis aims to describe the texture of the rocks and the percentage of minerals, which will be used to determine the protolith rock, metamorphism facies and the determination of contact metamorphism zone. The lithology found in Mount Selo Gajah from oldest to youngest are clastic limestone with intercalation of marl, marl with intercalation of sandstone, porphyritic andesite intrusions, hornfels, and pyroclastic breccia. Metamorphic rocks on Selo Gajah Hill is the product of contact metamorphism of carbonate rock which was intruded by porphyritic andesite intrusion. The metamorphism facies found in the research area are hornblende hornfels and pyroxene hornfels with the protolith rock is carbonate rocks.
  • NI 43-101 Independent Technical Report Mount Pleasant North Zone Preliminary Assessment Mount Pleasant Property Southwestern

    NI 43-101 Independent Technical Report Mount Pleasant North Zone Preliminary Assessment Mount Pleasant Property Southwestern

    330 Alison Blvd. Fredericton, New Brunswick Canada, E3C 0A9 Telephone: (506) 454-2359 Facsimile: (506) 454-2355 NI 43-101 Independent Technical Report Mount Pleasant North Zone Preliminary Assessment Mount Pleasant Property Southwestern New Brunswick, Canada Effective Date: January 22nd, 2010 FINAL REPORT PROJECT NUMBER 6526-03 REVISION: 02 Prepared By: J. Dean Thibault, P. Eng. Thibault & Associates Inc. Tim R. McKeen, P. Eng. Thibault & Associates Inc. Stephanie M. Scott, P. Eng. Thibault & Associates Inc. Trevor Boyd, P. Geo. Consultant for Adex Mining Inc. Andrew Hara, P. Eng. Hara Mining Enterprises Inc. Prepared For: Adex Mining Inc. Toronto, Ontario, Canada NI 43-101 Independent Technical Report Mount Pleasant North Zone Preliminary Assessment TABLE OF CONTENTS SECTION 1.0 SUMMARY ............................................................................................................ 1-1 1.1 Background ....................................................................................................................... 1-1 1.2 Geology and Exploration................................................................................................... 1-2 1.3 Resource Estimate............................................................................................................ 1-2 1.4 Mining................................................................................................................................ 1-3 1.5 Processing........................................................................................................................
  • Statistics and Segmentation: Using Big Data to Assess Cascades Arc

    Statistics and Segmentation: Using Big Data to Assess Cascades Arc

    This article is a non-peer reviewed preprint published at EarthArXiv. The article is in review by Geochimica et Cosmochimica Acta. 1 Statistics and segmentation: 2 Using Big Data to assess Cascades Arc compositional variability 3 Bradley W. Pitcher1 and Adam JR. Kent2 4 5 1Earth and Environmental Sciences department, Vanderbilt University, Nashville, TN 32701. 6 Email: [email protected] 7 2College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97333. 8 Email: [email protected] 9 10 11 Abstract 12 Primitive lavas erupted in the Cascades arc of western North America demonstrate significant 13 patterns of along-arc heterogeneity. Such compositional diversity may be the result of 14 differences in mantle melting processes, subduction geometry, regional tectonics, or 15 compositions of the slab, mantle or overlying lithosphere. Previous authors have partitioned the 16 arc into four geochemically distinct segments in order to assess the importance and relative roles 17 of these potential causes (Schmidt et al., 2008). However, despite the immense amount of data 18 available from the Cascade arc, no previous study has utilized a statistical approach on a 19 comprehensive dataset to address such a fundamental petrologic question. To better characterize 20 the heterogeneity of the entire arc, we compiled >250,000 isotopic, major, and trace element 21 analyses (glass and whole rock) from nearly 13,000 samples. To minimize inherent sampling 22 bias – the effect where well-studied volcanoes heavily weight conclusions – we use a weighted 23 bootstrap Monte Carlo approach in which the probability of a sample being selected to the 24 posterior distribution was inversely proportional to the number of samples within its 0.25° 25 latitude bin.
  • Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    PROCESSING AND CHARACTERIZATION OF BASALT FIBER REINFORCED CERAMIC COMPOSITES FOR HIGH TEMPERATURE APPLICATIONS USING POLYMER PRECURSORS Sarah B. Cox, Donovan Lui, Xin Wang, Jihua Gou Department of Mechanical and Aerospace Engineering University of Central Florida Orlando, FL, 32816 ABSTRACT The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000°C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200°C, β-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing. 1. INTRODUCTION In the aerospace industry, as the need for high performance vehicles grows, the need for materials which can meet these high performance levels becomes even more important.
  • Pleistocene Volcanism in the Anahim Volcanic Belt, West-Central British Columbia

    Pleistocene Volcanism in the Anahim Volcanic Belt, West-Central British Columbia

    University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2014-10-24 A Second North American Hot-spot: Pleistocene Volcanism in the Anahim Volcanic Belt, west-central British Columbia Kuehn, Christian Kuehn, C. (2014). A Second North American Hot-spot: Pleistocene Volcanism in the Anahim Volcanic Belt, west-central British Columbia (Unpublished doctoral thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/25002 http://hdl.handle.net/11023/1936 doctoral thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY A Second North American Hot-spot: Pleistocene Volcanism in the Anahim Volcanic Belt, west-central British Columbia by Christian Kuehn A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY GRADUATE PROGRAM IN GEOLOGY AND GEOPHYSICS CALGARY, ALBERTA OCTOBER, 2014 © Christian Kuehn 2014 Abstract Alkaline and peralkaline magmatism occurred along the Anahim Volcanic Belt (AVB), a 330 km long linear feature in west-central British Columbia. The belt includes three felsic shield volcanoes, the Rainbow, Ilgachuz and Itcha ranges as its most notable features, as well as regionally extensive cone fields, lava flows, dyke swarms and a pluton. Volcanic activity took place periodically from the Late Miocene to the Holocene.
  • Data of Geochemistry

    Data of Geochemistry

    Data of Geochemistry ' * Chapter W. Chemistry of the Iron-rich Sedimentary Rocks GEOLOGICAL SURVEY PROFESSIONAL PAPER 440-W Data of Geochemistry MICHAEL FLEISCHER, Technical Editor Chapter W. Chemistry of the Iron-rich Sedimentary Rocks By HAROLD L. JAMES GEOLOGICAL SURVEY PROFESSIONAL PAPER 440-W Chemical composition and occurrence of iron-bearing minerals of sedimentary rocks, and composition, distribution, and geochemistry of ironstones and iron-formations UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1966 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price 45 cents (paper cover) CONTENTS Page Face Abstract. _ _______________________________ Wl Chemistry of iron-rich rocks, etc. Continued Introduction. _________ ___________________ 1 Oxide facies Continued Iron minerals of sedimentary rocks __ ______ 2 Hematitic iron-formation of Precambrian age__ W18 Iron oxides __ _______________________ 2 Magnetite-rich rocks of Mesozoic and Paleozoic Goethite (a-FeO (OH) ) and limonite _ 2 age___________-__-._____________ 19 Lepidocrocite (y-FeO(OH) )________ 3 Magnetite-rich iron-formation of Precambrian Hematite (a-Fe2O3) _ _ _ __ ___. _ _ 3 age._____-__---____--_---_-------------_ 21 Maghemite (7-Fe203) __ __________ 3 Silicate facies_________________________________ 21 Magnetite (Fe3O4) ________ _ ___ 3 Chamositic ironstone____--_-_-__----_-_---_- 21 3 Silicate iron-formation of Precambrian age_____ 22 Iron silicates 4 Glauconitic rocks__-_-____--------__-------- 23 4 Carbonate facies______-_-_-___-------_---------- 23 Greenalite. ________________________________ 6 Sideritic rocks of post-Precambrian age._______ 24 Glauconite____ _____________________________ 6 Sideritic iron-formation of Precambrian age____ 24 Chlorite (excluding chamosite) _______________ 7 Sulfide facies___________________________ 25 Minnesotaite.
  • Oligocene and Miocene Arc Volcanism in Northeastern California: Evidence for Post-Eocene Segmentation of the Subducting Farallon Plate

    Oligocene and Miocene Arc Volcanism in Northeastern California: Evidence for Post-Eocene Segmentation of the Subducting Farallon Plate

    Origin and Evolution of the Sierra Nevada themed issue Oligocene and Miocene arc volcanism in northeastern California: Evidence for post­Eocene segmentation of the subducting Farallon plate Joseph P. Colgan1,*, Anne E. Egger2, David A. John1, Brian Cousens3, Robert J. Fleck1, and Christopher D. Henry4 1U.S. Geological Survey, 345 Middlefield Road, Mail Stop 973, Menlo Park, California 94025, USA 2Geological and Environmental Sciences, Stanford University, 450 Serra Mall, Stanford, California 94305, USA 3Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S5B6 4Nevada Bureau of Mines and Geology, University of Nevada, Reno, Nevada 89557, USA ABSTRACT sitionally similar to Oligocene rocks in the Unlike the western Cascades, however, vol­ Warner Range. They are distinctly different canic rocks of the ancestral Cascades are a subset The Warner Range in northeastern Cali- from younger (Late Miocene to Pliocene) of a diverse and widespread suite of Cenozoic fornia exposes a section of Tertiary rocks over high-Al, low-K olivine tholeiites, which are volcanic rocks erupted across the Basin and 3 km thick, offering a unique opportunity to more mafic (46%–49% SiO2), did not build Range Province since the Eocene. The ancestral study the long-term history of Cascade arc large edifices, and are thought to be related Cascades samples plotted in Figure 1 are those volcanism in an area otherwise covered by to backarc extension. The Warner Range is considered by du Bray et al. (2009) to be plausi­ younger volcanic rocks. The oldest locally
  • Description of Map Units

    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.
  • A Walk Back in Time the Ruth Canstein Yablonsky Self-Guided Geology Trail

    A Walk Back in Time the Ruth Canstein Yablonsky Self-Guided Geology Trail

    The cross section below shows the rocks of the Watchung Reservation and surrounding area, revealing the relative positions of the lava flows that erupted in this region and the sedimentary rock layers between them. A Walk Back in Time The Ruth Canstein Yablonsky Self-Guided Geology Trail click here to view on a smart phone NOTES Trailside Nature & Science Center 452 New Providence Road, Mountainside, NJ A SERVICE OF THE UNION COUNTY BOARD OF UNION COUNTY (908) 789-3670 CHOSEN FREEHOLDERS We’re Connected to You! The Ruth Canstein Yablonsky Glossary basalt a fine-grained, dark-colored Mesozoic a span of geologic time from Self-Guided Geology Trail igneous rock. approximately 225 million years ago to 71 million years This booklet will act as a guide for a short hike to interpret the geological history bedrock solid rock found in the same area as it was formed. ago, and divided into of the Watchung Reservation. The trail is about one mile long, and all the stops smaller units called Triassic, described in this booklet are marked with corresponding numbers on the trail. beds layers of sedimentary rock. Jurassic and Cretaceous. conglomerate sedimentary rock made of oxidation a chemical reaction “Watchung” is a Lenape word meaning “high hill”. The Watchung Mountains have an rounded pebbles cemented combining with oxygen. elevation of about 600 feet above sea level. As you travel southeast, these high hills are the together by a mineral last rise before the gently rolling lowland that extends from Rt. 22 through appropriately substance (matrix) . Pangaea supercontinent that broke named towns like Westfield and Plainfield to the Jersey shore.
  • 48. Iron and Carbon Isotope Evidence for Microbial Iron Respiration

    48. Iron and Carbon Isotope Evidence for Microbial Iron Respiration

    Earth and Planetary Science Letters 303 (2011) 121–132 Contents lists available at ScienceDirect Earth and Planetary Science Letters journal homepage: www.elsevier.com/locate/epsl Iron and carbon isotope evidence for microbial iron respiration throughout the Archean Paul R. Craddock ⁎, Nicolas Dauphas Origins Laboratory, Department of the Geophysical Sciences and Enrico Fermi Institute, The University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60637, United States article info abstract Article history: Banded Iron-Formations (BIFs) are voluminous chemical sediments that are rich in iron-oxide, carbonate and Received 17 August 2010 silica and whose occurrence is unique to the Precambrian. Their preservation in the geological record offers Received in revised form 20 December 2010 insights to the surface chemical and biological cycling of iron and carbon on early Earth. However, many details Accepted 22 December 2010 regarding the role of microbial activity in BIF deposition and diagenesis are unresolved. Laboratory studies have Available online 22 January 2011 + shown that reaction between carbon and iron through microbial iron respiration [2Fe2O3∙nH2O+CH2O+7H → 2+ − Editor: R.W. Carlson 4Fe +HCO3 +(2n+4)H2O+chemical energy] can impart fractionation to the isotopic compositions of these elements. Here, we report iron (δ56Fe, vs. IRMM-014) and carbon isotopic (δ13C, vs. V-PDB) compositions of Keywords: magnetite and of iron-rich and iron-poor carbonates in BIFs from the late Archean (~2.5 Ga) Hamersley Basin, iron-formation Australia and the early Archean (~3.8 Ga) Isua Supracrustal Belt (ISB), Greenland. The range of δ56Fe values Hamersley measured in the Hamersley Basin, including light values in magnetite and heavy values in iron-rich carbonates Isua (up to +1.2‰), are incompatible with their precipitation in equilibrium with seawater.