Part I Introduction and General Aspects of Metamorphism
1 Definition, Conditions and Types of Metamorphism .............. 3
1.1 Conditions of Metamorphism ............................... 4
1.1.1 Low-Temperature Limit of Metamorphism ............. 4
1.1.2 High-Temperature Limit of Metamorphism ............ 5
1.1.3 Low-Pressure Limit of Metamorphism ................ 7
1.1.4 High-Pressure Limit of Metamorphism ............... 7
1.2 Types of Metamorphism .................................... 8
1.2.1 Orogenic Metamorphism ............................. 8
1.2.2 Ocean-Floor Metamorphism ......................... 11
1.2.3 Other Types of Regional Metamorphism ............. 11
1.2.4 Contact Metamorphism ............................. 13
1.2.5 Cataclastic Metamorphism ......................... 14
1.2.6 Hydrothermal Metamorphism ........................ 14
1.2.7 Other Types of Small-Scale Metamorphism .......... 16
References and Further Reading .......................... 17
2 Metamorphic Rocks ............................................ 21
2.1 Primary Material of Metamorphic Rocks ................... 22
2.1.1 Chemical Composition of Protoliths
of Metamorphic Rocks ............................. 23
2.1.2 Chemical Composition Classes of Metamorphic
Rocks and Their Protoliths ....................... 25
2.2 The Structure of Metamorphic Rocks ...................... 26
2.3 Classification and Names of Metamorphic Rocks ........... 29
2.3.1 Rock Names Referring to the Structure ............ 31
2.3.2 Names for High-Strain Rocks ...................... 32
2.3.3 Special Terms .................................... 33
2.3.4 Modal Composition of Rocks ....................... 35
2.3.5 Names Related to the Origin of the Protolith ..... 35
2.4 Mineral Assemblages and Mineral Parageneses ............. 36
2.5 Graphical Representation of Metamorphic Mineral
Assemblages ............................................. 39
2.5.1 Mole Numbers, Mole Fractions and the Mole
Fraction Line .................................... 39
2.5.2 The Mole Fraction Triangle ....................... 41
2.5.3 Projections ...................................... 43
References and Further Reading .......................... 55
3 Metamorphic Processes ........................................ 57
3.1 Principles of Metamorphic Reactions ..................... 58
3.2 Pressure and Temperature Changes in Crust and Mantle .... 65
3.2.1 General Aspects .................................. 65
3.2.2 Heat Flow and Geotherms .......................... 66
3.2.3 Temperature Changes and Metamorphic Reactions .... 71
3.2.4 Pressure Changes in Rocks ........................ 72
3.3 Gases and Fluids ........................................ 74
3.4 Time Scale of Metamorphism .............................. 76
3.5 Pressure-Temperature-Time Paths and Reaction History .... 77
3.6 Chemical Reactions in Metamorphic Rocks ................. 81
3.6.1 Reactions Among Solid-Phase Components ........... 82
3.6.2 Reactions Involving Volatiles as Reacting
Species .......................................... 83
3.7 Reaction Progress ....................................... 99
3.8 Phase Diagrams ......................................... 102
3.8.1 Phase Diagrams, General Comments and Software ... 102
3.8.2 The Phase Rule .................................. 103
3.8.3 Construction of Phase Diagrams for
Multicomponent Systems After the Method of
Schreinemakers .................................. 105
3.8.4 Use of Phase Diagrams, an Example ............... 109
References and Further Reading ......................... 113
4 Metamorphic Grade ........................................... 119
4.1 General Considerations ................................. 119
4.2 Index Minerals and Mineral Zones ....................... 120
4.3 Metamorphic Facies ..................................... 122
4.3.1 Origin of the Facies Concept .................... 122
4.3.2 Metamorphic Facies Scheme ....................... 124
4.3.3 Pressure-Temperature Conditions of Metamorphic
Facies .......................................... 131
4.4 Isograds ............................................... 131
4.4.1 The Isograd Concept ............................. 131
4.4.2 Zone Boundaries, Isograds and Reaction-
Isograds ........................................ 133
4.4.3 Assessing Isograds, Isobars and Isotherms ....... 135
4.5 Bathozones and Bathograds .............................. 139
4.6 Petrogenetic Grid ...................................... 141
4.6.1 Polymorphic Transitions .......................... 142
4.7 Geothermobarometry ..................................... 146
4.7.1 Concept and General Principle ................... 147
4.7.2 Assumptions and Precautions ..................... 149
4.7.3 Exchange Reactions .............................. 153
4.7.4 Net-Transfer .................................... 158
4.7.5 Miscibility Gaps and Solvus Thermometry ......... 162
4.7.6 Uncertainties in Thermobarometry ................ 166
4.7.7 Thermobarometry Using Multi-equilibrium
Calculations (MET) .............................. 167
4.8 Gibbs Method ........................................... 168
4.9 Assemblage Stability Diagrams .......................... 170
4.10 More P-T Tools ......................................... 171
4.10.1 Reactions Involving Fluid Species .............. 171
4.10.2 P-T Tools for Very Low Grade Rocks ............. 173
References and Further Reading ......................... 174
Part II Metamorphism of Specific Rock Types
5 Metamorphism of Ultramafic Rocks ............................ 191
5.1 Introduction ........................................... 191
5.2 Ultramafic Rocks ....................................... 191
5.2.1 Rock Types ...................................... 193
5.2.2 Chemical Composition ............................ 194
5.3 Metamorphism in the MSH System ......................... 196
5.3.1 Chemographic Relations in the MSH System ........ 196
5.3.2 Progressive Metamorphism of Maximum Hydrated
Harzburgite ..................................... 198
5.4 Metamorphism in the CMASH System ....................... 202
5.4.1 Progressive Metamorphism of Hydrated Al-
Bearing Lherzolite .............................. 202
5.4.2 Effects of Rapid Decompression and Uplift
Prior to Cooling ................................ 204
5.5 Isograds in Ultramafic Rocks ........................... 204
5.6 Mineral Assemblages in the Uppermost Mantle ............ 206
5.7 Serpentinization of Peridotite ......................... 208
5.8 Ultramafic Rocks at High Temperature ................... 210
5.9 Thermometry and Geobarometry in Ultramafic Rocks ....... 211
5.10 Carbonate-Bearing Ultramafic Rocks ..................... 212
5.10.1 Metamorphism of Ophicarbonate Rocks ............ 212
5.10.2 Soapstone and Sagvandite ....................... 215
5.11 Open System Reactions in Ultramafic Rocks .............. 219
5.12 Potassium-Bearing Peridotites .......................... 221
References and Further Reading ......................... 221
6 Metamorphism of Dolomites and Limestones .................... 225
6.1 Introduction ........................................... 225
6.1.1 Rocks ........................................... 225
6.1.2 Minerals and Rock Composition ................... 227
6.1.3 Chemographic Relationships ...................... 228
6.2 Orogenic Metamorphism of Siliceous Dolomite ............ 230
6.2.1 Modal Evolution Model ............................ 232
6.3 Orogenic Metamorphism of Limestone ..................... 233
6.4 Contact Metamorphism of Dolomites ...................... 235
6.4.1 Modal Evolution Model ............................ 238
6.5 Contact Metamorphism of Limestones ..................... 239
6.6 Isograds and Zone Boundaries in Marbles ................ 243
6.7 Metamorphic Reactions Along Isothermal Decompression
Paths .................................................. 244
6.8 Marbles Beyond the CMS-НС System ....................... 246
6.8.1 Fluorine ........................................ 247
6.8.2 Aluminium ....................................... 248
6.8.3 Potassium ....................................... 248
6.8.4 Sodium .......................................... 251
6.9 Thermobarometry of Marbles ............................. 251
6.9.1 Calcite-Dolomite Miscibility Gap ................. 252
6.10 High-Pressure and Ultrahigh-Pressure Metamorphism
of Carbonate Rocks ..................................... 252
References and Further Reading ......................... 253
7 Metamorphism of Pelitic Rocks (Metapelites) ................. 257
7.1 Metapelitic Rocks ...................................... 257
7.2 Pelitic Sediments ...................................... 257
7.2.1 General ......................................... 257
7.2.2 Chemical Composition ............................ 258
7.2.3 Mineralogy ...................................... 258
7.3 Pre-metamorphic Changes in Pelitic Sediments ........... 258
7.4 Intermediate-Pressure Metamorphism of Pelitic Rocks .... 259
7.4.1 Chemical Composition and Chemography ............ 259
7.4.2 Mineral Assemblages at the Beginning of
Metamorphism .................................... 260
7.4.3 The ASH System .................................. 262
7.4.4 Metamorphism in the FASH System ................. 264
7.4.5 Mica-Involving Reactions ........................ 267
7.4.6 Metamorphism in the KFMASH System (AFM
System) ......................................... 269
7.5 Low-Pressure Metamorphism of Pelites ................... 278
7.5.1 FASH System ..................................... 278
7.5.2 KFMASH System ................................... 280
7.6 High-Temperature Metamorphism of Pelites: Metapelitic
Granulites ............................................. 284
7.6.1 Cordierite-Garnet-Opx-Spinel-Olivine
Equilibria ...................................... 285
7.6.2 The Excess Quartz Condition ..................... 286
7.6.3 Partial Melting and Migmatite ................... 288
7.6.4 More About Granulites ........................... 292
7.7 Metamorphism of Mg-rich "Pelites" ...................... 296
7.8 High Pressure: Low Temperature Metamorphism of
Pelites ................................................ 298
7.9 Additional Components in Metapelites ................... 302
References and Further Reading ......................... 306
8 Metamorphism of Marls ....................................... 315
8.1 General ................................................ 315
8.2 Orogenic Metamorphism of Al-Poor Marls ................. 316
8.2.1 Phase Relationships in the KCMAS-HC System ...... 317
8.2.2 Prograde Metamorphism in the KCMAS-HC System
at Low XCo2 ..................................... 319
8.3 Orogenic Metamorphism of Al-Rich Marls ................. 321
8.3.1 Phase Relationships in the CAS-HC System ........ 323
8.3.2 Phase Relationships in the KNCAS-HC System ...... 325
8.4 Increasing Complexity of Metamarls ..................... 332
8.5 Low Pressure Metamorphism of Marls ..................... 333
References and Further Reading ......................... 336
9 Metamorphism of Mafic Rocks ................................. 339
9.1 Mafic Rocks ............................................ 339
9.1.1 Hydration of Mafic Rocks ........................ 340
9.1.2 Chemical and Mineralogical Composition of
Mafic Rocks ..................................... 342
9.1.3 Chemographic Relationships and ACF Projection ... 343
9.2 Overview of Metamorphism of Mafic Rocks ................ 348
9.2.1 Plagioclase in Mafic Rocks, Equilibria in the
Labradorite System (NCASH System) ............... 352
9.3 Subgreenschist Facies Metamorphism ..................... 353
9.3.1 General Aspects ................................. 353
9.3.2 Metamorphism in the CMASH and NCMASH Systems .... 356
9.3.3 Transition to Greenschist Facies ................ 362
9.4 Greenschist Facies Metamorphism ........................ 363
9.4.1 Introduction .................................... 363
9.4.2 Mineralogical Changes Within the Greenschist
Facies .......................................... 363
9.4.3 Greenschist-Amphibolite Facies Transition ....... 365
9.5 Amphibolite Facies Metamorphism ........................ 367
9.5.1 Introduction .................................... 367
9.5.2 Mineralogical Changes Within the Amphibolite
Facies .......................................... 367
9.5.3 Low-Pressure Series Amphibolites ................ 368
9.5.4 Amphibolite-Granulite Facies Transition ......... 370
9.6 Granulite Facies and Mafic Granulites .................. 371
9.7 Blueschist Facies Metamorphism .................... 374
9.7.1 Introduction .................................... 374
9.7.2 Reactions and Assemblages ....................... 374
9.8 Eclogite Facies Metamorphism ........................... 378
9.8.1 Eclogites ....................................... 378
9.8.2 Reactions and Assemblages ....................... 380
9.8.3 Eclogite Facies in Gabbroic Rocks ............... 383
References and Further Reading ......................... 387
10 Metamorphism of Quartzofeldspathic Rocks .................... 395
10.1 Quartzofeldspathic Rocks ............................... 395
10.2 Metagraywackes ......................................... 395
10.2.1 Introduction .................................... 395
10.2.2 Metamorphism of Metagraywacke (Metaspammitic)
Compositions .................................... 397
10.2.3 Oogenic Metamorphism of Metagraywackes .......... 398
10.2.4 Contact Metamorphism of Metagraywackes and
Metapsammites ................................... 400
10.3 Granitoids ............................................. 406
10.3.1 Prehnite and Pumpellyite ........................ 406
10.3.2 Stilpnomelane ................................... 406
10.3.3 The Microcline-Sanidine Isograd ................. 407
10.3.4 Eclogite and Blueschist Facies Granitoids ....... 408
10.3.5 Migmatitic Granitoids and Charnockite ........... 409
References and Further Reading ......................... 411
Appendix: Symbols for rock forming minerals .................... 415
Index .......................................................... 419
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