17. Microstructures in Natural Serpentinite Gouges

Chapters in this book

1. Frontmatter i
2. Preface vii
3. Subject index ix
4. An Overview of Fault Rocks 1
5. Brittle Behavior. Geometrical characteristics and microstructures
6. 1 . Fault Zone in Granodiorite 20
7. 2. Brittle Deformation of a Granite 22
8. 3. Brittle Structures in a Normal-Sense Fault Zone 28
9. 4· Kinematic Indicators in Brittle Fault Zones 30
10. 5. Fault-Rock Microstructures in Basalt and Diabase from the Upper Ocean Crust 32
11. 6. Cohesive Crush Breccias, Microbreccias, and Cataclasites in Granitic Foota/Vall of a Normal Fault 36
12. 7. Deformation of Granitic Rocks at Shallow Crustal Levels 38
13. 8. Influence of Biotite and Foliation on Brittle Deformation of Gneiss 40
14. 9. Strengthening of Fault Breccia By K-Feldspar Cementation 42
15. 10. Quartz Microstructures in a Fault Process Zone 44
16. 11. Catacustic Deformation of Quartzite Revealed by Cathodoluminescence 46
17. 12. Microstructural Variations in a Cataclastic Quartz Fault Rock 48
18. Brittle Behavior. Cataclasis and gouge development
19. 13. Progressive Development of Foliation in a Brittle Deformation Zone 52
20. 14. Multiple Generation Cataclasites 54
21. 15. Banded Structures in Gouge 56
22. 16. Foliated Fault Gouges 58
23. 17. Microstructures in Natural Serpentinite Gouges 62
24. 18. Mesoscopic Ductility in Fault Gouges 66
25. 19. Shear Band Fabric in Gouge 68
26. 20. Cataclastic Fabrics in Experimental Shear Zones 70
27. 21 . Evolution of Gouge Textures in Experimental Granite Faults 72
28. Brittle Behavior. Pseudotachylyte
29. 22. Pseudotachylyte Type Area: The Vredefort Structure, South Africa 76
30. 23. Pseudotachylyte Formed By Frictional Fusion 80
31. 24. Flow Features and Cataclasite-Pseudotachylyte Relations 88
32. 25. Melting Relations within Lithic Clasts in Pseudotachylyte 90
33. 26. Amygdules within Pseudotachyme 92
34. 27. Amygdules and Microbreccia Collapse Structure in a Pseudotachylyte 94
35. 28. Mesoscopic and Microscopic Aspects of Pseudotachylyte 96
36. 29. Coeval Mylonites And Pseudotachylyte 98
37. 30. Pseudotachylyte-Bearing Strike-Slip Faults in Mylonitic Rocks 104
38. 31 . Progressive Fracturing and Twinning Related to Pseudotachylyte Generation 108
39. 32. Glassy And Microlitic Pseudotachylytes 112
40. 33. Pseudotachylyte from a Metamorphic Core Complex 122
41. 34. Development of Ultramylonite from Pseudotachylyte in a Metamorphic Core Complex 124
42. 35. Deep Crustal Eclogite-Facies Pseudotaotywes 126
43. Brittle Behavior. Fluid-related features
44. 36. Vein Development in Reverse Fault Zones 130
45. 37. Slickenlines Produced Experimentally at Hydrothermal Conditions 136
46. 38. Microscale Vein Mineralization and Porphyroclast Development in Low-Grade Cataclasites 138
47. Semi-Brittle Behavior. Geometrical Characteristics And Microstructures
48. 39- Anastomosing Deformation Zones 142
49. 40- Dilational Fractures that Preceded Formation of Shear Zones 144
50. 41. Strike-Slip Shear Zone in Granodiorite 146
51. 42. Cataclasites and Mylonites 152
52. 43. Protomylonite, Augen Mylonite, Protocataclasite, and Cataclasite in Granitic Footwall of a Detachment Fault 160
53. 44. Fault Rocks from an Exhumed, Intracrustal, Extensional Detachment 164
54. 45. Semi-Brittle Deformation in Quartzo-Feldspathic Mylonites 170
55. 46. Brittle-Ductile Deformation of Feldspar 172
56. 47. Plastic-To-Brittle Deformation Of Microcline During Deformation And Cooling Of A Granitic Pluton 176
57. 48. Semi-Brittle Deformation and Cataclastic Flow of Hornblende-Quartz Rock in a Ductile Shear Zone 180
58. 49. Reaction Weakening in Phyllonites Derived from Granite 184
59. 50. Brittle-Ductile Fault Rocks in a Basement-Cored Thrust Sheet 186
60. 51. Fault Rocks from the Mid-Atu\Ntic Ridge at 24°N 194
61. 52. Cataclastic to Crystal-Plastic Transition in Halite Shear Zones 198
62. 53. Cataclastic Flow of Feldspar Aggregates 200
63. Semi-Brittle Behavior. Fluid-Related Features
64. 54. Coupled Mass Transfer and Microfracturing in Gabbroic Mylonites 204
65. 55. Fluid Flow Mechanisms in Mylonites: Evidence from Compositional Zoning Patterns 208
66. 56. Fluid Flow Mechanisms In Mylonites: Evidence From Microcracks 210
67. 57. Fluid Flow Mechanisms in Mylonites: Pervasive and Channelized Flow in Carbonates 212
68. 58. Rb-Sr Study of an Ultramylonite Zone in Granitic Orthogneiss 214
69. 59. Ductile-Brittle and Reaction-Assisted Deformation in Sheared Granitoid 218
70. 60. Fluid-Filled Pores in Mylonitic Rocks 220
71. 61. Old" and "New" Grains in Quartz Mylonite 222
72. Ductile Behavior. Strain Partitioning and other Geometric Characteristics
73. 62. Heterogeneous Shear Zones in Granodiorite Carol Simpson 226
74. 63. Strain Partitioning Associated with a Mylonitic Shear Zone-Detachment Fault System 228
75. 64. Heterogeneous Deformation of Tonalite and Pegmatite Vein 232
76. 65. Some Mesoscopic Aspects of Mylonitic Shear Zones 234
77. 66. Anastomosing Character Of Mylonitic Foliation 236
78. 67. Strain Partitioning In A Granulite-Facies Shear Zone: I. Mesoscopic Features 238
79. 68. Strain Partitioning in a Granulite-Facies Shear Zone: II. Microscopic Features 240
80. 69. Strain Heterogeneity Over Space and Time in a Granitic Shear Zone 242
81. 70. Olivine and Quartz Tectonites Related to Intra-Oceanic Thrusting 244
82. 71. Asymmetric Boudinage in Mylonitic Gneisses 246
83. 72. Tensile Fracture within Elastic-Brittle Inclusions of Tourmaline 248
84. 73. Microstructural Development in Aplite with Progressive Strain 250
85. 74. Formation of Ductile Shear Zones Along Preexisting Faults in Feldspathic Rocks 252
86. 75· Variation in Relative Recrystallized Grain Sizes of Quartz and Feldspar with Deformation Temperature 256
87. 76. Oblique Grain-Shape Preferred Orientation in Quartzo-Feldspathic and Calcitic Mylonites 260
88. 77. Oblique Grain-Shape Fabrics in a Mylonitic Quartz Vein 264
89. 78. Natural Examples of Low-Temperature, Grain-Boundary Migration Recrystallization 266
90. 79. Natural Examples of Rotation Recrystallization 268
91. 80. High-Temperature Grain-Boundary and Phase-Boundary Migration 270
92. 81 . Recrystallization of Biotite by Subgrain Rotation 272
93. 82. Microstructural Development in a Quartzo-Feldspathic Mylonitic Shear Zone 274
94. 83. Deformation Microstructure of Natural Plagioclase 276
95. 84. Kink Bands and Recrystallization in Plagioclase 278
96. 85. Ductility of Garnet Indicating High-Temperature Deformation 280
97. 86. Dating Deformation in Mylonites 282
98. 87. Grain-Scale Microstructures in an Experimental Mylonite 288
99. Ductile Behavior. Foliation Development
100. 88. Development of Foliation in Sheared Adamellite 292
101. 89. Banding and Foliation in Mylonites 296
102. 90. Progressive Development of Foliation in a Lower Greenschist-Facies Ductile Deformation Zone 298
103. 91. Development of Foliation in Mylonites 300
104. 92. Foliation Heterogeneities in Mylonites 302
105. Ductile Behavior. Composite Foliations In Mylonites
106. 93. S-C Fabric in Granites 306
107. 94. Composite Puvnar Fabrics and Asymmetric Development of Myrmekite in Orthogneiss 312
108. 95. S-C Fabrics Formed in Syntectonic Plutons During the Transition from Magmatic to High-Temperature Subsolidus Conditions 316
109. 96. Mylonitic Deformation of a Gfianitoid Rock 318
110. 97. Low-Angle Crenulation Cleavage in Micaceous Mylonites 322
111. 98. Composite Planar Fabric in Mylonites 324
112. 99. Shear Bands in Quartzose Phyllonite 326
113. 100. Normal-Sense Mylonites in Granitic Rocks 328
114. 101. Experimental Shearing of Quartzite and Quartz-Feldspar Aggregate 330
115. Ductile Behavior. Porphyroclasts in Mylonites
116. 102. Rotated Porphyroclast Systems in Quartzo-Feldspathic Mylonites 334
117. 103. Mica Fish in Quartzite Mylonites 340
118. 104. Shear Bands and Asymmetric Porphyroclasts in a Mylonitic Amphibolite 342
119. 105. Winged Porphyroclasts: Simple Shear/General Noncoaxial Shear 344
120. 106. String-Bead Fabric: Homogeneity of Noncoaxial Strain 346
121. 107. Mantled Porphyroclasts 348
122. 108. Sense-of-Shear Indicators (In Three Dimensions) in Mylonitic Granitic Rocks 350
123. 109. Rotated Porphyroclasts in Mylonites 354
124. 110. δ Clast In An Experimental Mylonite 356
125. Ductile Behavior. Ductile Behavior
126. 111. Folds and other Mesoscopic Structural Features Associated with an Extensional Mylonitic Shear Zone 360
127. 112. Curvature of Hinge Lines about a Stretching Lineation 364
128. 113. Folding in Experimental Mylonites 366
129. Ductile Behavior. Evidence of Coaxial Deformational Histories
130. 114. Coaxial Deformation in Quartzite Mylonite 370
131. 115. Deformational History Indicators? 374
132. 116. Transition from granodiorite to phyllonite 376
133. 117. Preferred orientation and microstructure of mylonitic carbonate rocks 378
134. DUCTILE BEHAVIOR. Metamorphic grade variations
135. 118. Fault rocks from Ben Arnaboll, Moine thrust zone, northwest Scotland 382
136. 119. Greenschist-facies mylonite zone in quartzo-feldspathic gneiss 392
137. 120. Progressive mylonitization of arkose along a major thrust fault 398
138. 121. Progressive mylonitization of diabase dikes along a major thrust fault 400
139. 122. Retrogressive mylonitic metabasic fault rocks 402
140. 123. Serpentinite mylonites from an ophiolite 408
141. 124. Microstructures in chalcopyrite mylonites 412
142. Ductile Behavior. Metamorphic Grade Variations
143. 125. High-Temperature Mylonites: I 418
144. 126. High-Temperature Mylonites: II 422
145. 127. Gabbro Mylonite Developed Along a Crustal-Scale Decollement 426
146. 128. High-Temperature Mylonites: I. Metabasic Mylonites 428
147. 129. High-Temperature Mylonites: II. Ultrabasic Mylonites 436
148. 130. High-Temperature Mylonites: III. Metasedimentary Mylonites 440
149. 131. Mesoscopic Kinematic Indicators in a Melt-Rich, High-Grade Shear Zone 442
150. 132. Kinematic Indicators in Eclogite-Facies Shear Zones 444
151. Ductile Behavior. Metamorphic Grade Variations
152. 133. Post-Deformational Recovery Of Microstructure in Sheared Octachloropropane (C₃Cl₈) 450
153. 134. Blastocataclasite: A Possible Rock Type from the Bottom of the Seismic Zone 454
154. 135. Retrograde and Annealed Mylonites 456
155. 136. Effects of Static Annealing on Experimentally Deformed Quartzite and Aplite 462
156. Ductile Behavior. Fluid-Related Features
157. 137. Evidence for Chemical Processes in the Evolution of Mylonites 466
158. 138. Mineral Reactions Participating in Intragranular Fracture Propagation: Subcritical Crack Growth ? 468
159. 139. Interaction of Chemical and Mechanical Factors in Biotite Deformation 470
160. 140. Effects of Deformation on Isotopic Exchange in Quartzite 472
161. Ductile Behavior. Microstructural Development Of Mylonitic Rocks Of Specific Composition
162. 141. Progressive Development of a Quartz Mylonite 478
163. 142. Mylonitic Fabric Transition in an Extensional Tectonic Setting 480
164. 143. Quartzite Fabric Transition in a Cordilleran Metamorphic Core Complex 484
165. 144. Quartz Mylonites from the Moine Thrust Zone at the Stack of Glencoul, Northwest Scotland 490
166. 145. Quartz Mylonites from the Moine Thrust Zone in Southern Assynt, Northwest Scotland 494
167. 146. Dislocation Creep Regimes in Experimentally Deformed Quartz Aggregates 496
168. 147. Dislocation Creep Regimes in Naturally Deformed Quartz Aggregates 500
169. Ductile Behavior. Microstructural Development of Mylonitic Rocks Of Specific Composition
170. 148- Progressive Deformation of Plagiocuvse In Ductile Shear Zones 504
171. 149. Plagioclase Porphyroclasts in a High-Temperature Shear Zone 506
172. 150. Evidence for Granular Flow in Feldspar-Dominated Lithologies 508
173. 151. Feldspar Transformation Reactions Mediating Superplastic Flow 512
174. 152. Anorthosite Mylonites Produced by Superplastic Flow 514
175. 153. Feldspathic Mylonites 516
176. 154. Tonalite Mylonite Formed During Crustal Exhumation 518
177. 155. Mylonitization and Remobilization of Monzogranite During Metamorphism and Intrusion 520
178. 156. Intrusion and Ductile Deformation in a Long-Lived Batholithic Shear Zone 524
179. 157. Recrystallization-Accommodated Dislocation Creep in Albite Aggregates 528
180. Ductile Behavior. Microstructural Development of Mylonitic Rocks of Specific Composition
181. 158. Partly Recrystallized Calcite in Naturally Deformed Marble 532
182. 159. Marble Mylonites 536
183. 160. Deformation and Dynamic Recrystallization of Dolomite 540
184. 161. Experimental Dynamic Recrystallization of Calcite Rocks 542
185. 162. Comparison of Experimental and Natural Superplastic Deformation of Fine-Grained Calcite Rocks 544
186. 163. Deformation Mechanisms and Fabric Development in Fine-Grained Calcite Rocks 546
187. 164. Natural Calcite Mylonitic Rocks 548
188. Ductile Behavior. Microstructural Development of Mylonitic Rocks of Specific Composition
189. 165. Low-Temperature Mylonite in Rock Salt 552
190. 166. Active Mylonites in Neoproterozoic Rock Salt 554
191. 167. An Active Nappe in Neoproterozoic Rock Salt 556
192. 168. Deformation of Anhydrite: Dislocation Creep to Diffusion Creep 558
193. Ductile Behavior. Microstructural Development of Mylonitic Rocks of Specific Composition
194. 169. Metamorphic Sole of an Ophiolite 564
195. 170. Mylonitic Shear Zones Associated with Dike Intrusion in An Ophiolite 566
196. 171. Deformed Oceanic Plutonic Rocks 570
197. 172. Plastically Deformed Oceanic Gabbros 572
198. Ductile Behavior. Microstructural Development of Mylonitic Rocks of Specific Composition
199. 173. Microstructures in Low- and High-Temperature Serpentinite Mylonites 578
200. 174. Microstructures Formed During Shear Localization in the Upper Mantle 582
201. 175. Asthenospheric Deformation in Ophiolitic Peridotite 588
202. 176. Lithospheric Deformation in Ophiolitic Peridotite 590
203. 177. Peridotite Mylonite Produced ny Superplastic Flow 592
204. References Cited 595
205. Index 615