The Metamorphosis of Metamorphic Petrology
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Editorial for Special Issue “Ore Genesis and Metamorphism: Geochemistry, Mineralogy, and Isotopes”
minerals Editorial Editorial for Special Issue “Ore Genesis and Metamorphism: Geochemistry, Mineralogy, and Isotopes” Pavel A. Serov Geological Institute of the Kola Science Centre, Russian Academy of Sciences, 184209 Apatity, Russia; [email protected] Magmatism, ore genesis and metamorphism are commonly associated processes that define fundamental features of the Earth’s crustal evolution from the earliest Precambrian to Phanerozoic. Basically, the need and importance of studying the role of metamorphic processes in formation and transformation of deposits is of great value when discussing the origin of deposits confined to varied geological settings. In synthesis, the signatures imprinted by metamorphic episodes during the evolution largely indicate complicated and multistage patterns of ore-forming processes, as well as the polygenic nature of the mineralization generated by magmatic, postmagmatic, and metamorphic processes. Rapid industrialization and expanding demand for various types of mineral raw ma- terials require increasing rates of mining operations. The current Special Issue is dedicated to the latest achievements in geochemistry, mineralogy, and geochronology of ore and metamorphic complexes, their interrelation, and the potential for further prospecting. The issue contains six practical and theoretical studies that provide for a better understanding of the age and nature of metamorphic and metasomatic transformations, as well as their contribution to mineralization in various geological complexes. The first article, by Jiang et al. [1], reports results of the first mineralogical–geochemical Citation: Serov, P.A. Editorial for studies of gem-quality nephrite from the major Yinggelike deposit (Xinjiang, NW China). Special Issue “Ore Genesis and The authors used a set of advanced analytical techniques, that is, electron probe microanaly- Metamorphism: Geochemistry, sis, X-ray fluorescence (XRF) spectrometry, inductively coupled plasma mass spectrometry Mineralogy, and Isotopes”. -
Real-Time AFM Diagrams on Your Macintosh
Spear Geological Materials Research v.1, n.3, p.1 Real-time AFM diagrams on your Macintosh Frank S. Spear Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute Troy, NY 12180 USA <[email protected]> (Received December 15, 1998; Published May 25, 1999) Abstract An algorithm is presented for the calculation of stable AFM mineral assemblages in the KFMASH system based on an internally consistent thermodynamic data set and the petrogenetic grid derived from this data set. The P-T stability of each divariant (three-phase) AFM assemblage is determined from the bounding KFASH, KMASH and KFMASH reactions. Macintosh regions (enclosed areas defined by a sequence of x-y points) are created for each divariant region. The Macintosh toolbox routine ÒPtInRgnÓ (point-in-region) is used to determine whether a user- specified P and T falls within the stability limit of each assemblage, and the compositions of minerals in the stable assemblages are calculated and plotted. Implementation of the algorithm is coded in FORTRAN as a module for program Gibbs (Spear and Menard, 1989). Users can calculate individual AFM diagrams at any P-T condition within the limits of the P-T grid, and sequences of AFM diagrams along any P-T path. Diagrams can be saved as PICT images for creating animations. The internally consistent thermodynamic data sets of Holland and Powell (1998) and Spear and Cheney (unpublished) are supported. The algorithm and its implementation provide a useful tool for researchers to explore the implications of a petrogenetic grid and to compare predictions of different thermodynamic data sets. -
Metamorphic Rocks (Lab )
Figure 3.12 Igneous Rocks (Lab ) The RockSedimentary Cycle Rocks (Lab ) Metamorphic Rocks (Lab ) Areas of regional metamorphism Compressive Compressive Stress Stress Products of Regional Metamorphism Products of Contact Metamorphism Foliated texture forms Non-foliated texture forms during compression during static pressure Texture Minerals Other Diagnostic Metamorphic Protolith Features Rock Name Non-foliated calcite, dolomite cleavage faces of Marble Limestone calcite usually visible quartz quartz grains are Quartzite Quartz Sandstone intergrown Foliated clay looks like shale but Slate Shale breaks into layers muscovite, biotite very fine-grained, but Phyllite Shale has a sheen like satin muscovite, biotite, minerals are large Schist Shale may have garnet enough to see easily, muscovite and biotite grains are parallel to each other feldspar, biotite, has layers of different Gneiss Any protolith muscovite, quartz, minerals garnet amphibole layered black Amphibolite Basalt or Andesite amphibole grains Texture Minerals Other Diagnostic Metamorphic Protolith Features Rock Name Non-foliated calcite, dolomite cleavage faces of Marble Limestone calcite usually visible quartz quartz grains are Quartzite Quartz Sandstone intergrown Foliated clay looks like shale but Slate Shale breaks into layers muscovite, biotite very fine-grained, but Phyllite Shale has a sheen like satin muscovite, biotite, minerals are large Schist Shale may have garnet enough to see easily, muscovite and biotite grains are parallel to each other feldspar, biotite, has layers of different Gneiss Any protolith muscovite, quartz, minerals garnet amphibole layered black Amphibolite Basalt or Andesite amphibole grains Identification of Metamorphic Rocks 12 samples 7 are metamorphic 5 are igneous or sedimentary Protoliths and Geologic History For 2 of the metamorphic rocks: Match the metamorphic rock to its protolith (both from Part One) Write a short geologic history of the sample 1. -
Metamorphic Rocks Reminder Notes
Metamorphic Rocks Reminder notes: • Metamorphism • Metasomatism • Regional metamorphism • Contact metamorphism • Protolith • Prograde • Retrograde • Fluids – dewatering and decarbonation – volatile flux • Chemical change vs textural changes • Mud to gneiss Metamorphism – changes in mineralogy and texture of a rock due to changes in pressure and temperature. The bulk chemical composition of the rock doesn’t change. Metasomatism – changes in mineralogy and texture of a rock due to changes in pressure, temperature, and chemistry. Chemically active fluids move ions from one place to another which changes the bulk chemistry of the rock. These fluids come from the breakdown of hydrous and carbonate minerals. Contact versus Regional metamorphism Metamorphic Facies Plotting metamorphic mineral diagrams Barrovian metamorphic sequences Thermodynamics and Gibbs free energy • Reactions take place in a direction that lowers Gibbs free energy • Equilibrium is achieved only when Gibbs free energy reaches a minimum • At equilibrium, temperature, pressure, and chemical potentials of all components must be the same throughout • Equilibrium thermodynamics and kinetics. Thermodynamics tells us what can happen, kinetics tells us if it does happen Petrogenetic Grid AKFM diagram for pelitic rocks Petrogenetic grid – reactions in metapelites for greenschist and amphibolite facies Assemblages in metapelites as a function of metamorphic grade Role of Fluids in Metamorphism CaCO3 + SiO2 = CaSiO3 + CO2 (fluid) Ca2Mg5Si8O22(OH)2 + 3CaCO3 = 4CaMgSi2O6 + CaMg(CO3)2 + H2O + CO2 tremolite calcite diopside dolomite fluid Metamorphic grade, index minerals, isograds, and metamorphic facies Textures of metamorphic rocks • Excess energy present in deformed crystals (elastic), twins, surface free energy • Growth of new grains leads to decreasing free energy – release elastic energy, reduce surface to volume ratio (increase grains size, exception occurs in zones of intense shearing where a number of nuclei are formed). -
University Microfilms, a XEROX Company, Ann Arbor, Michigan
i 71-22,648 SWAINBANK, Richard Charles, 1943- GEOCHEMISTRY AND PETROLOGY OF ECLOGITIC ROCKS IN THE FAIRBANKS AREA, ALASKA. University of Alaska, Ph.D., 1971 Geology University Microfilms, A XEROX Company, Ann Arbor, Michigan THIS DISSERTATION HAS BEEN MICROFILMED EXACTLY AS RECEIVED Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. GEOCHEMISTRY AND PETROLOGY OF ECLOGITIC ROCKS IN THE FAIRBANKS AREA, ALASKA A DISSERTATION Presented to the Faculty of the University of Alaska in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY by Richard Charles Swainbank B. Sc. M. Sc. College, Alaska May 1971 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. GEOCHEMISTRY AND PETROLOGY OF ECLOGITIC ROCKS IN THE FAIRBANKS AREA, ALASKA APPROVED: 7 ^ ■ APPROVED: £ DATE: Dean of the College of Earth Science and Mineral Industry Vice President for Research and Advanced Study Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. a b s t r a c t Eclogites have generally been considered to be compositionally analogous to basic igneous rocks and to have been recrystallized at high temperatures and/or pressures. A group of eclogitic rocks in the Fairbanks area are new composi tional variants and are, together with more orthodox eclogites, an essential unit within a metasedimentary sequence, which has recrystal lized under lower amphibolite facies conditions. Chemical analyses of the unusual calcite-bearing eclogitic rocks strongly suggest that they are derived from sedimentary parents akin to calcareous marls. The clinopyroxenes from these eclogites are typical omphacites, and the coexistant garnets are typical of garnets from eclogites in blue schist terrane. -
MSA PRESIDENTIAL ADDRESS Metamorphism and the Evolution of Subduction on Earth
American Mineralogist, Volume 104, pages 1065–1082, 2019 MSA PRESIDENTIAL ADDRESS Metamorphism and the evolution of subduction on Earth MICHAEL BROWN1,* AND TIM JOHNSON2,3 1Laboratory for Crustal Petrology, Department of Geology, University of Maryland, College Park, Maryland 20742, U.S.A. Orcid 0000-0003-2187-616X 2School of Earth and Planetary Sciences, The Institute for Geoscience Research (TIGeR), Curtin University, GPO Box U1987, Perth, West Australia 6845, Australia. Orcid 0000-0001-8704-4396 3Center for Global Tectonics, State Key Laboratory for Geological Processes and Mineral Resources, China University of Geosciences, Wuhan, Hubei Province, 430074, China ABSTRACT Subduction is a component of plate tectonics, which is widely accepted as having operated in a manner similar to the present-day back through the Phanerozoic Eon. However, whether Earth always had plate tectonics or, if not, when and how a globally linked network of narrow plate boundaries emerged are mat- ters of ongoing debate. Earth’s mantle may have been as much as 200–300 °C warmer in the Mesoarchean compared to the present day, which potentially required an alternative tectonic regime during part or all of the Archean Eon. Here we use a data set of the pressure (P), temperature (T), and age of metamorphic rocks from 564 localities that vary in age from the Paleoarchean to the Cenozoic to evaluate the petrogenesis and secular change of metamorphic rocks associated with subduction and collisional orogenesis at convergent plate boundaries. Based on the thermobaric ratio (T/P), metamorphic rocks are classified into three natural groups: high T/P type (T/P > 775 °C/GPa, mean T/P ~1105 °C/GPa), intermediate T/P type (T/P between 775 and 375 °C/GPa, mean T/P ~575 °C/GPa), and low T/P type (T/P < 375 °C/GPa, mean T/P ~255 °C/GPa). -
Petrology of the Metamorphic Rocks
Petrology of the metamorphic rocks Second Edition Roger Mason London UNWIN HYMAN Boston Sydney Wellington © R. Mason, 1990 This book is copyright under the Berne Convention. No reproduction without permission. All rights reserved. Published by the Academic Division of Unwin Hyman Ltd 15/17 Broadwick Street, London WIV IFP, UK Unwin Hyman Inc. 955 Massachusetts Avenue, Cambridge, MA 02139, USA Allen & Unwin (Australia) Ltd 8 Napier Street, North Sydney, NSW 2060, Australia Allen & Unwin (New Zealand) Ltd in association with the Port Nicholson Press Ltd Compusales Building, 75 Ghuznee Street, Wellington I, New Zealand First published in 1990 British Library Cataioguing in Publication Data Mason, Roger 1941- Petrology of the metamorphic rocks. - 2nd ed. I. Metamorphic rocks. Petrology I. Title 552.4 ISBN 978-0-04-552028-2 ISBN 978-94-010-9603-4 (eBook) DOI 10.1007/978-94-010-9603-4 Library of Congress Cataioging-in-Publication Data Mason, Roger, 1941- Petrology of the metamorphic rocks/Roger Mason. - 2nd ed. p. cm. Includes bibliographical references. 1. Rocks, Metamorphic. I. Title. QE475.A2M394 1990 552·.~c20 90-35106 CIP Typeset in 10 on 12 point Times by Computape (Pickering) Ltd, North Yorkshire Preface There has been a great advance in the understanding of processes of meta morphism and of metamorphic rocks since the last edition of this book appeared. Methods for determining temperatures and pressures have become almost routine, and there is a wide appreciation that there is not a single temperature and pressure of metamorphism, but that rocks may preserve, in their minerals, chemistry and textures, traces of their history of burial, heating, deformation and permeation by fluids. -
Geology and Petrology of the Hirao Limestone and the Tagawa Metamorphic Rocks−With Special Reference to the Contact Metamorphism by Cretaceous Granodiorite
GeologyJournal and of Mineralogicalpetrology of the and Hirao Petrological Limestone Sciences, and the Volume Tagawa 99 ,metamorphic page 25─41, 2004 rocks 25 Geology and petrology of the Hirao Limestone and the Tagawa metamorphic rocks−with special reference to the contact metamorphism by Cretaceous granodiorite * ** *** Mayuko FUKUYAMA , Kensaku URATA and Tadao NISHIYAMA *Graduate School of Science and Technology, Kumamoto University, Kurokami 2-39-1, Kumamoto 860-8555 **Department of Geography, Tokyo Metropolitan University, Minami-Osawa 1-1, Hachioji, Tokyo 192-0397 ***Department of Earth Sciences, Kumamoto University, Kurokami, 2-39-1, Kumamoto 860-8555 The Hirao Limestone located in northeast Kyushu is bordered on the north by unmetamorphosed Paleozoic stra- ta (the Kagumeyoshi Formation), and on the south by the Tagawa metamorphic rocks, a member of the Sangun Metamorphic Rocks. They are thermally metamorphosed due to the Cretaceous Hirao granodiorite intrusion. As a result, neither the fossil record nor the record of the regional (Sangun) metamorphism has been preserved. We investigated the geologic relationships among these units. The tectonic collage model associated with ac- cretionary processes proposed by Kanmera and Nishi (1983) seems the most reasonable. The Hirao Limestone and the uppermost part of the Tagawa metamorphic rocks may be a large olistolith formed during the accretion of the Palaeozoic formation. Petrological studies show that the area was thermally metamorphosed as revealed by widespread occur- rences of biotite in pelitic rocks both in the Tagawa metamorphic rocks and in the Kagumeyoshi Formation. Garnet occurrences in the pelitic schists close to the Hirao granodiorite suggest about 700°C for the peak meta- morphic temperature of contact metamorphism, based on garnet-biotite geothermometers. -
The Dalradian Rocks of the North-East Grampian Highlands of Scotland
Revised Manuscript 8/7/12 Click here to view linked References 1 2 3 4 5 The Dalradian rocks of the north-east Grampian 6 7 Highlands of Scotland 8 9 D. Stephenson, J.R. Mendum, D.J. Fettes, C.G. Smith, D. Gould, 10 11 P.W.G. Tanner and R.A. Smith 12 13 * David Stephenson British Geological Survey, Murchison House, 14 West Mains Road, Edinburgh EH9 3LA. 15 [email protected] 16 0131 650 0323 17 John R. Mendum British Geological Survey, Murchison House, West 18 Mains Road, Edinburgh EH9 3LA. 19 Douglas J. Fettes British Geological Survey, Murchison House, West 20 Mains Road, Edinburgh EH9 3LA. 21 C. Graham Smith Border Geo-Science, 1 Caplaw Way, Penicuik, 22 Midlothian EH26 9JE; formerly British Geological Survey, Edinburgh. 23 David Gould formerly British Geological Survey, Edinburgh. 24 P.W. Geoff Tanner Department of Geographical and Earth Sciences, 25 University of Glasgow, Gregory Building, Lilybank Gardens, Glasgow 26 27 G12 8QQ. 28 Richard A. Smith formerly British Geological Survey, Edinburgh. 29 30 * Corresponding author 31 32 Keywords: 33 Geological Conservation Review 34 North-east Grampian Highlands 35 Dalradian Supergroup 36 Lithostratigraphy 37 Structural geology 38 Metamorphism 39 40 41 ABSTRACT 42 43 The North-east Grampian Highlands, as described here, are bounded 44 to the north-west by the Grampian Group outcrop of the Northern 45 Grampian Highlands and to the south by the Southern Highland Group 46 outcrop in the Highland Border region. The Dalradian succession 47 therefore encompasses the whole of the Appin and Argyll groups, but 48 also includes an extensive outlier of Southern Highland Group 49 strata in the north of the region. -
Metamorphic Rocks
Metamorphism and metamorphic rocks GEOL115 Alexander Lusk Outline: • Metamorphic rocks – Defini>on and major types of metamorphism – Rock cycle • Metamorphic processes • Deformaon and development of a foliaon/ schistosity/cleavage • Progressive (prograde) metamorphic series • Environments of metamorphism • Metamorphic facies Metamorphic rocks If pre-exis>ng rocks (e.g. igneous, sedimentary, metamorphic) are buried within in the Earth, new minerals can grow in the solid rock through recrystallizaon and the rock can deform in response to tectonic forces. This rock may have started off as a sediment of mud or clay, which later become a sedimentary rock such as mudstone or shale … What minerals are present? Recall the rock cycle: Recall where different rock types form: Types of metamorphism Regional metamorphism: as rocks are buried deeper and deeper within the earth they are subject to increasingly higher pressures and temperatures, which result in recrystallization. The directed pressures (stresses) produce planar structures called foliation. Contact metamorphism: rocks within the crust that are intruded by magma are recrystallized by the magma’s high temperatures. These rocks are commonly not deformed (foliated). Processes involved: 1. Neomineralizaon – growth of new minerals replacing minerals that become unstable. 2. Grain growth – growth of new or exis>ng mineral grains. 3. Deformaon – creates a schistosity or foliaon defined by the orientaon of platy or elongate mineral grains. Neomineralizaon Porphyroblasts: Porphyroclasts: Grain growth: -
Relative Dating of Rock Sequences Rocks Tell Their Stories All That Remains Is for Us to Observe and Infer Their History. 1
Relative Dating of Rock Sequences Rocks Tell Their Stories All that remains is for us to observe and infer their history. Look at the 2 illustrations in this lesson which show several horizontally layered sedimentary rock layers, igneous intrusions and faults. They have been numbered and lettered for ease of reference. In this lesson we will tell the "story" of the rock sequences by observing certain characteristics: 1- The order in which the rock layers appear. 2- Erosional Surfaces 3- Unconformities If you need help with the submergence , emergence and unconformity issues, go to Submergence and Emergence of Rock Layers With Respect to Sea Level, look at the illustrations and read the captions. The Key: Be sure to look at the key before observing the series of illustrations. Notice that not only do symbols exist for sandstone, shale and conglomerate, but also for the loose sediments that will eventually lithify to become these rock types. Go On To Page 2 Let the Stories Begin! L. Immoor 2006 Geoteach.com 1 This is the "story" for Rock Sequence 1: 1- Submergence followed by Deposition and the Formation of layers 1 and 2 (the sandstone and limestone). 2- Emergence and Erosion of layer 2 (limestone). 3- Submergence followed by Deposition and the Formation of layer 3, (the shale) producing an unconformity with layer 2 (limestone). The unconformity is evidenced by the wavy, eroded top surface of a rock layer. 4- Igneous Intrusion A with resulting Contact Metamorphism of layers 1, 2 and 3 (the sandstone, limestone and shale). 5- Emergence and Erosion of layer 3 (shale) and Igneous Intrusion A. -
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).