Essentials of Igneous and Metamorphic Petrology

331 Pages·2013·30.54 MB·English

E S S E N T I A L S O F
IG NEOUS
AN D
METAMORPHIC
PE T ROLOGY
B. RONALD FROS T | CAROL D. FROS T
Essentials of Igneous and
Metamorphic Petrology
All geoscience students need to understand the origins, environments, and basic processes that produce
igneous and metamorphic rocks. Th is concise textbook, written specifi cally for one-semester undergradu-
ate courses, provides students with the key information they need to understand these processes. Topics
are organized around the types of rocks to expect in a given tectonic environment, rather than around rock
classifi cations: this is much more interesting and engaging for students, as it applies petrology to real geologic
environments. Th is textbook includes over 250 illustrations and photos, and is supplemented by additional
color photomicrographs made freely available online. Application boxes throughout the text encourage stu-
dents to consider how petrology connects to wider aspects of geology, including economic geology, geologic
hazards, and geophysics. End-of-chapter exercises allow students to apply the concepts they have learned and
to practice interpreting petrologic data.
B. Ronald Frost is a professor of geology at the University of Wyoming, where he performs wide-ranging
research on igneous and metamorphic petrology as well as ore deposits. He has authored more than 110
scientifi c papers on topics ranging from serpentinization and the metamorphism of serpentinites, ocean
fl oor metamorphism, granulites, thermobarometry, the geochemistry of granites, and melting of sulfi de
ore deposits. He has conducted extensive fi eld research in the Precambrian basement of Wyoming, as
well as in Siberia, Greenland, northern Canada, and the Broken Hill area of Australia. He received the
Alexander von Humboldt Research Award from the German government. He has been an associate edi-
tor for the Journal of Metamorphic Geology and Geochimica et Cosmochimica Acta , and currently serves
on the editorial board of the Journal of Petrology . He is a member of the American Geophysical Union,
the Society of Economic Geologists, and the Geochemical Society, and a fellow of the Mineralogical
Society of America. He has taught mineralogy, petrology, optical mineralogy, and ore deposits for more
than thirty-fi ve years.
Carol D. Frost is a professor in the Department of Geology and Geophysics at the University of
Wyoming. She investigates the origin and evolution of the continental crust, the provenance of clastic
sedimentary rocks, and granite petrogenesis, and she applies isotope geology and geochemistry to envi-
ronmental issues including water coproduced with hydrocarbons and geological sequestration of carbon
dioxide. She is the author of more than 120 scientifi c papers. She is a fellow of the Mineralogical Society
of America and serves as the science editor for the Geological Society of America’s journal, Geosphere .
She was awarded the CASE Wyoming Professor of the Year award in 2001. In 2008, she received her uni-
versity’s highest faculty award, the George Duke Humphrey medal, recognizing teaching eff ectiveness,
distinction in scholarly work, and distinguished service to the university and to the state. She has served
in the administration of the University of Wyoming as director of the School of Energy Resources, asso-
ciate vice president for research and economic development, and vice president for special projects, and
she currently serves as associate provost.
Th e two authors are unrelated.
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Essentials of
Igneous and
Metamorphic
Petrology
B. Ronald Frost
UNIVERSITY OF WYOMING
Carol D. Frost
UNIVERSITY OF WYOMING
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32 Avenue of the Americas, New York, NY 10013-2473, USA
Cambridge University Press is part of the University of Cambridge.
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www.cambridge.org
Information on this title: www.cambridge.org /9781107696297
© B. Ronald Frost and Carol D. Frost 2014
Th is publication is in copyright. Subject to statutory exception
and to the provisions of relevant collective licensing agreements,
no reproduction of any part may take place without the written
permission of Cambridge University Press.
First published 2014
Printed in the United States of America
A catalogue record for this publication is available from the British Library.
Library of Congress Cataloging in Publication data
Frost, Bryce Ronald, 1947- Essentials of igneous and metamorphic petrology / B.
Ronald Frost, Carol D. Frost. p. cm.
Includes bibliographical references and index.
ISBN 978-1-107-02754-1 (hardback : alk. paper)
1. Igneous rocks. 2. Metamorphic rocks. I. Frost, Carol D.
(Carol Denison) II. Title.
QE461.F767 2014
552’.1–dc23 2013012168
ISBN 978-1-107-02754-1 Hardback
ISBN 978-1-107-69629-7 Paperback
Cambridge University Press has no responsibility for the persistence or accuracy of
URLs for external or third-party Internet Web sites referred to in this publication
and does not guarantee that any content on such Web sites is, or will remain,
accurate or appropriate.
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Contents
List of Figures page xi 2.5.1 Th e Ternary System Mg SiO –
2 4
List of Tables xix CaAl Si O – CaMgSi O 30
2 2 8 2 6
List of Maps xx 2.6 Implications for Petrology 31
List of Boxes xxii Summary 32
Questions and Problems 32
Preface xxiii
Further Reading 35
Acknowledgments xxv
3
1
Introduction to Silicate Melts
Introduction to Igneous Petrology 1
and Magmas 36
1.1 Introduction 1
3.1 Introduction 36
1.2 Th e Scope of Igneous Petrology 2
3.2 Th e Role of Volatiles 37
1.3 Classifi cation of Igneous Rocks 2
3.2.1 Role of H O 37
1.3.1 Preliminary Classifi cation 3 2
3.2.2 Role of CO 38
1.3.2 IUGS Classifi cation of Plutonic 2
3.3 Physical Properties of Magma 39
Rocks 3
3.3.1 Temperature 39
1.3.3 IUGS Classifi cation of Volcanic and
3.3.2 Heat Capacity and Heat of Fusion 39
Hypabyssal Rocks 5
3.3.3 Viscosity 39
1.4 Igneous Textures 5
3.3.4 Density 40
1.4.1 Crystal Size 6
3.4 Th e Ascent of Magmas 40
1.4.2 Crystal Shape 7
3.5 Magmatic Diff erentiation 42
1.5 Igneous Structures 8
3.5.1 Partial Melting 42
1.5.1 Structures in Volcanic Flows 8
3.5.2 Crystallization Processes 42
1.5.2 Structures in Pyroclastic Deposits 10
3.5.3 Liquid-liquid Fractionation 4 3
1.5.3 Structures in Hypabyssal Rocks 1 2
3.5.4 Assimilation 4 3
1.5.4 Structures in Plutonic Rocks 1 4
3.5.5 Magma Mixing 44
Summary 16
Summary 44
Questions and Problems 16
Questions and Problems 45
Further Reading 17
Further Reading 46
2
4
An Introduction to Igneous Phase
The Chemistry of Igneous Rocks 47
Diagrams 18
4.1 Introduction 47
2.1 Introduction 18
4.2 Modal Mineralogy versus Normative
2.2 Th e Phase Rule 19
Mineralogy 48
2.3 Th e Lever Rule 20
4.3 Variation Diagrams Based on Major
2.4 Two Component Systems Involving Melt 21
Elements 48
2.4.1 Binary Systems with a Eutectic 2 1
4.4 Major Element Indices of Diff erentiation 51
2.4.2 Binary Systems with a Peritectic 2 4
4.4.1 Modifi ed Alkali-lime Index 53
2.4.3 Binary Systems with a Th ermal
4.4.2 Iron Enrichment Index 5 4
Barrier 2 6
4.4.3 Aluminum Saturation Index 5 5
2.4.4 Binary Systems with Solid Solution 27
4.4.4 Alkalinity Index 5 6
2.4.5 Binary Systems with Partial Solid
4.5 Identifi cation of Diff erentiation Processes
Solution 29
Using Trace Elements 56
2.5 Phase Diagrams of Ternary Systems 29
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vi Contents
4.5.1 Use of Trace Elements to Model 7
Melting and Crystallization
Convergent Margin Magmatism 88
Processes 57
7.1 Introduction 88
4.5.2 Graphical Representations of Trace Element
7.2 Oceanic and Continental Arcs 89
Compositions 58
7.2.1 Island Arc Magmatism 89
4.6 Application of Stable and Radioactive
7.2.2 Continental Arc Magmatism 8 9
Isotopes in Igneous Petrology 59
7.2.3 Structure of Island and Continental
4.6.1 Geochronology 60
Arcs 91
4.6.2 Isotopic Tracing of Magma Sources 60
7.2.4 Examples of Island and Continental
Summary 61
Arcs 92
Questions and Problems 62
7.3 Petrographic Characteristics of Island
Further Reading 64
and Continental Arc Rocks 97
5 7.3.1 Petrography of Island Arc Rocks 9 7
7.3.2 Petrography of Continental Arc
Basalts and Mantle Structure 65
Rocks 9 9
5.1 Introduction 65 7.4 Geochemical Characteristics of
5.2 Basalt Petrology 66 Convergent Margin Magma Series 99
5.2.1 Classifi cation 66 7.4.1 Comparison of Oceanic and Arc
5.2.2 Chemistry and Petrography 66 Diff erentiation Trends 99
5.3 Melt Generation from the Mantle 67 7.4.2 Comparison of Island and
5.3.1 Mantle Composition 6 7 Continental Arc Magma Series 100
5.3.2 Crust and Mantle Structure 6 7 7.4.3 Comparison of Oceanic and
5.3.3 Mechanisms for Partial Melting Continental Arc (Cordilleran)
of the Mantle 6 8 Plutonic Complexes 1 02
5.3.4 Th e Process of Mantle Melting 68 7.4.4 Geochemical Identifi cation of
5.3.5 Origin of Th oleiitic versus Alkali Contrasting Processes Forming
Basalts 6 9 Seguam and Mount Saint Helens 103
5.4 Environments where Magmas are 7.5 Magma Generation at Convergent
Generated 70 Margins 104
Summary 70 Summary 105
Questions and Problems 71 Questions and Problems 106
Further Reading 71 Further Reading 106
6 8
Oceanic Magmatism 72 Intracontinental Volcanism 107
6.1 Introduction 72 8.1 Introduction 107
6.2 Th e Petrology and Structure of the Ocean Crust 8.2 Continental Flood Basalt Provinces 108
73 8.2.1 Th e Columbia Plateau – Snake
6.2.1 Ophiolites as a Model of the Ocean River Plain Province 1 09
Crust 73 8.2.2 Petrography and Chemistry of
6.2.2 Refi nements of the Ophiolite Model 7 4 Continental Flood Basalts 1 11
6.3 Petrography and Geochemistry 8.2.3 Models for the Generation of
of Oceanic Magmatism 78 Continental Flood Basalts 1 11
6.3.1 Mid-ocean Ridge Basalt 78 8.3 Bimodal Volcanism 112
6.3.2 Off -ridge Magmatism 80 8.3.1 Bimodal Volcanism in the
Summary 86 Yellowstone – Snake River Plain
Questions and Problems 86 Province 112
Further Reading 87
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Contents vii
8.3.2 Geochemistry of the Yellowstone – 10.4.1 Th e Etive Granite 150
Snake River Plain Bimodal Suite 1 14 10.4.2 Geochemistry and Origin of Caledonian
8.3.3 Models for the Generation of Bimodal Granites 151
Volcanism 115 10.5 Review of the Four Main Granite Types 152
8.4 Alkaline Volcanism 115 Summary 156
8.4.1 Sodic Alkaline Magmatism of the Questions and Problems 156
East African Rift 116 Further Reading 156
8.4.2 Potassic Alkaline Volcanism 1 18
8.5 Origin of the Chemical Diversity of 11
Intracontinental Basaltic Magmas 121
Introduction to Metamorphic
Summary 122
Petrology 157
Questions and Problems 122
Further Reading 122 11.1 Introduction 157
11.2 Th e Scope of Metamorphism 158
9 1 1.3 T ypes of Metamorphism 1 58
11.3.1 Regional Metamorphism 1 58
Intracontinental Plutonism 124
11.3.2 Contact Metamorphism 158
9.1 Introduction 124 11.3.3 Burial Metamorphism 158
9.2 Layered Mafi c Intrusions 126 11.3.4 Dynamic Metamorphism 159
9.2.1 Th e Bushveld Intrusion 1 28 11.3.5 Hydrothermal Metamorphism 1 59
9.2.2 Mineralogical Variation in LMIs 1 28 11.4 Basic Goals of Metamorphic Petrology 159
9.2.3 Granitic Rocks Associated with LMIs 129 11.5 Identifi cation of Protolith 159
9.2.4 Tectonic Environments of LMIs 130 11.5.1 Rocks of Clearly Sedimentary
9.3 Anorthosites and Related Rocks 130 Parentage 159
9.3.1 Archean Anorthosites 131 11.5.2 Rocks of Clearly Igneous Parentage 1 61
9.3.2 Massif Anorthosites 132 11.5.2 Rocks of Uncertain Parentage 1 61
9.4 Ferroan Granites 134 11.6 Determination of Metamorphic Textures 161
9.4.1 Th e Pikes Peak Batholith 1 35 11.6.1 Stability Range of Single Minerals 161
9.4.2 Th e Composition of Ferroan Granites 1 36 11.6.2 Stability of Mineral Assemblages 1 62
9.5 Alkaline Complexes 138 11.6.3 Metamorphic Facies 162
9.5.1 Geology of the Ilimaussaq Intrusion 1 38 11.6.4 Th ermobarometry 162
Summary 141 11.7 Metamorphic Textures 162
Questions and Problems 142 11.7.1 Primary Textures 1 62
Further Reading 143 11.7.2 Metamorphic Textures 164
11.8 Naming a Metamorphic Rock 166
10 Summary 167
Questions and Problems 168
Interpretation of Granitic Rocks 144
Further Reading 169
10.1 I ntroduction 144
10.2 Classifi cation of Granitic Rocks 145
12
10.2.1 Mineralogical Classifi cation 145
10.2.2 Classifi cation Based on Opaque Interpretation of Metamorphic
Oxides 1 45 Phase Diagrams 170
10.2.3 Alphabetic Classifi cation 145 12.1 Introduction 170
10.2.4 Geochemical Classifi cation 145 12.2 A Little History 171
10.3 Peraluminous Leucogranites 146 12.3 Use of Chemographic Projections 171
10.3.1 Himalayan Leucogranites 148 12.3.1 Chemographic Projections in a Two-
10.3.2 Geochemistry of Peraluminous Component System 172
Leucogranites 1 48 12.3.2 Chemographic Projections in a Th ree-
10.4 Caledonian Granites 149 Component System 173
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viii Contents
12.3.3 Chemographic Projections in Systems 14.4.2 Th e Upper Temperature Limits to
with Four and More Components 175 Metamorphism and Migmatites 1 99
Summary 176 14.4.3 Upper Pressure Limit of Metamorphism 2 00
Questions and Problems 176 Summary 201
Further Reading 179 Questions and Problems 202
Further Reading 202
13
15
Metamorphic Facies and the
Metamorphism of Mafi c Rocks 180 Metamorphism of Peridotitic Rocks 203
13.1 Introduction 180 15.1 Introduction 203
13.2 Defi nition of Metamorphic Facies 181 15.2 Th e Process of Serpentinization 204
13.3 Facies of Regional Metamorphism 181 15.3 Prograde Metamorphism of Serpentinite:
13.3.1 Greenschist Facies 1 81 Reactions in the System
13.3.2 Blueschist Facies 182 CaO-MgO-SiO -H O 204
2 2
13.3.3 Amphibolite Facies 183 15.4 Role of Minor Components 208
13.3.4 Very Low-Temperature 15.4.1 Iron 208
Metamorphism 184 15.4.2 Aluminum 2 10
13.3.5 Granulite Facies 185 15.5 Metaperidotites and Metamorphic Facies 211
13.3.6 Eclogite Facies 1 85 15.6 Role of CO in Metamorphism of
2
13.4 Facies of Contact Metamorphism 185 Peridotites 212
13.5 T extural Changes during Metamorphism 186 15.7 Metasomatism of Peridotites 214
13.6 Mafi c Mineral Assemblages at Increasing 15.8 Examples of Metaperidotites in the Field 215
Temperature and Pressure 187 15.8.1 Malenco Serpentinite 2 15
13.6.1 Relations at Very Low Temperatures 187 15.8.2 Ingalls Peridotite 217
13.6.2 Relations at Low Pressure with Summary 218
Increasing Temperature 1 88 Questions and Problems 218
13.6.3 Relations at Low Temperature with Further Reading 219
Increasing Pressure 189
Summary 189 16
Questions and Problems 189
Metamorphism of Pelitic Rocks 220
Further Reading 190
16.1 Introduction 220
16.2 Chemographic Projections for Pelitic
14
Systems 221
Thermobarometry and the Conditions 16.2.1 Chemographic Projections for
of Metamorphism 191 Continuous Reactions 221
14.1 Introduction 191 16.2.2 AMF Projections for Pelitic Rocks 2 23
14.2 Review of Th ermodynamics 192 16.3 Progressive Metamorphism of Pelitic Rocks:
14.2.1 Free Energy 192 Barrovian Metamorphism 224
14.2.2 Eff ect of Changes in Pressure and 16.3.1 Th e Protolith: Th e Mineralogy of
Temperature on ∆ G 192 Shale 224
14.2.3 Th e Equilibrium Constant 192 16.3.2 Low-Grade Metamorphism of Pelitic
14.2.4 Activity-composition Relations 1 93 Rocks 2 24
14.3 Th ermobarometers 194 16.3.3 Barrovian Metamorphism of Pelitic
14.3.1 Geothermometry 194 Schists 225
14.3.2 Geobarometry 1 95 16.4 Comparison between Barrovian and other
14.3.3 Th ermobarometry 196 P-T Conditions for Metamorphism of
14.4 C onditions of Metamorphism 197 Pelitic Rocks 229
14.4.1 Th e Pressure and Temperature 16.4.1 Correlation of Barrovian Zones to
Conditions for the Metamorphic Facies 198 Metamorphic Facies 2 29
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Contents ix
16.4.2 Pressure Information from Summary 259
Metapelitic Rocks 2 30 Questions and Problems 260
Summary 233 Further Reading 261
Questions and Problems 234
Further Reading 236 Appendix: Review of Mineralogy 263
A.1 Introduction 263
17 A.2 Leucocratic Rock-forming Minerals 263
A.2.1 Quartz 263
Metamorphism of Calcareous Rocks
A.2.2 Feldspars and Feldspathoids 263
and the Role of Fluids in
A.2.3 Carbonates 268
Metamorphism 237
A.3 Ferromagnesian Minerals 268
17.1 I ntroduction 237
A.3.1 Olivine 268
17.2 M etamorphism of Impure Dolomitic
A.3.2 Pyroxenes 269
Marble 238
A.3.3 Amphiboles 272
17.2.1 Stability of Metamorphic Assemblages
A.3.4 Phyllosilicates 274
in T-X Space 239
A.4 Aluminum-excess Minerals 277
17.2.2 Examples of How Mineral Assemblages
A.4.1 Aluminosilicates (Andalusite, Kyanite,
Can Monitor Fluid Flow in Aureoles 240
and Sillimanite) 277
17.3 Buff ering of other Fluid Components 242
A.4.2 Garnets 278
17.4 Buff ering of pH 244
A.4.3 Staurolite 278
Summary 246
A.4.4 Cordierite 278
Questions and Problems 247
A.4.5 Chloritoid 279
Further Reading 248
A.5 Ca-Al Silicates 279
A.5.1 Clinozoisite-Epidote 279
18
A.5.2 Prehnite 279
Regional Occurrence and Tectonic A.5.3 Pumpellyite 279
A.5.4 Lawsonite 280
Signifi cance of Metamorphic Rocks 249
A.5.5 Laumontite 280
18.1 I ntroduction 249
A.6 Oxide, Sulfi de, and other Nominally Opaque
18.2 Metamorphism along Convergent Plate
Phases 280
Margins 250
A.6.1 Fe-Ti Oxides (Magnetite and Ilmenite) 2 80
18.2.1 Characteristics of Low-Temperature,
A.6.2 Other Spinel Minerals 280
High-Pressure Belts 2 50
A.6.3 Fe Sulfi des 280
18.2.2 Characteristics of Low-Pressure,
A.6.4 Graphite 281
High-Temperature Belts 2 50
A.6.5 Rutile 281
18.2.3 Tectonic Interpretation 2 50
A.7 Accessory Minerals 281
18.3 Metamorphism in Continental Collisions 251
A.7.1 Zircon 281
18.3.1 Examples of Continental Collisions 252
A.7.2 Sphene (or Titanite) 281
18.4 Metamorphism in Rift ing Terrains 253
A.7.3 Apatite 281
18.5 Sea Floor Metamorphism 254
A.7.4 Monazite 281
18.6 Granulite Terranes 255
Summary 282
18.7 M etamorphism in Archean Terrains 257
References 283
18.7.1 Greenstone Belts 258
Index 297
18.7.2 Gneiss Terrains 258
18.7.3 Tectonic Interpretation of Archean
Metamorphic Belts 259
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