Point Defects in Minerals

Geophysical Monograph Series......Page 1
Point Defects in Minerals......Page 3
CONTENTS......Page 5
Preface......Page 7
Bibliography......Page 8
Introduction......Page 9
Defect Chemistry......Page 11
Ternary Compounds......Page 15
Summary......Page 20
References......Page 22
1. Introduction......Page 26
2. Atom Superposition and Electron Delocalization Theory......Page 28
3. Bonding in Representative Transition Metal Oxides......Page 29
Wustite, Hematite, and Magnetite......Page 30
4. Summary and Concluding Comments......Page 31
References......Page 32
2. Computer Modelling: Aims and Methodology......Page 34
3. Interatomic Potentials......Page 36
Study of Extended Defect Formation......Page 37
Crystal Structure Prediction......Page 38
5. Modelling of Silicates......Page 39
6. Structure Prediction for Silicates......Page 40
7. Future Developments......Page 41
References......Page 42
3. Molecular Dynamics Simulations of Liquids and Glasses: Methodology......Page 44
4. Molecular Dynamics Simulations of BeF2 and Si02......Page 45
5. Theory of Network Glasses and Liquids......Page 50
References......Page 54
2. Electrical Conduction......Page 55
3.1. Defect Chemical Approach......Page 56
3.2. Frenkel Disorder......Page 59
4. Carrier Mobilities......Page 60
4.2. Electronic Mobilities......Page 61
5. Electrical Conductivity Diagrams......Page 62
6.1. Impedance Measurements......Page 64
6.2. Transference Measurements......Page 66
6.4. Doping Dependence of Conductivity......Page 67
7.1. Magnesium Dioxide: MgO......Page 68
7.2. Fluorite Oxides: Ce0 Th0 2 , UO2......Page 70
8. Conclusions......Page 74
References......Page 75
Introduction......Page 77
Experimental Technique and Interpretation......Page 78
Results and Discussion......Page 79
Trivalent Substituents Cr, Al......Page 81
Tetravalent Substituent Fe104-Fe9TiO4......Page 82
Conclusions......Page 83
References......Page 84
Introduction......Page 86
Results......Page 87
Discussion......Page 89
Conclusions......Page 94
References......Page 95
Introduction......Page 96
Experimental Data......Page 97
Defect Reactions......Page 98
Discussion......Page 99
Conclusions......Page 102
References......Page 103
Materials......Page 105
Autoradiography......Page 107
Grain Boundary Profile Analyses......Page 108
Deriving Grain Boundary Diffusion Coefficients......Page 110
Discussion of the Data......Page 111
Discussion of the Oxygen Tracer Technique......Page 112
References......Page 113
The Hexagonal Close-Packed Matrix......Page 114
The Olivine Structure......Page 116
Material Transport Data......Page 118
The Correlation Factor......Page 119
Discussion of Oxygen Diffusion......Page 120
Summary and Conclusions......Page 121
References......Page 122
Determination of Diffusion Coefficients......Page 124
Cation Diffusion in Olivine Under Experimental Conditions......Page 125
Trace Element Diffusion in Natural Systems......Page 126
References......Page 128
Methods of Study......Page 130
Chemical Relationships Between Vacancies and Extended Defects......Page 131
The Role of Extended Defects in Solid-State Reactions......Page 132
The Role of Extended Defects in Diffusion......Page 134
Vacancy Non-Stoichiometry in Rock-Forming Minerals......Page 136
Conclusions......Page 137
References......Page 138
Theory......Page 140
Diffusional Creep of Model Polycrystalline Oxides......Page 143
References......Page 148
Introduction......Page 149
Specimen Material And Experimental Details......Page 150
Diffusion of Hydroxyl in Quartz at 1500 MPa, 900°C......Page 152
Natural Quartz Heat Treated in Water at 1500 MPa......Page 154
Wet Synthetic Quartz Heat Treated at 1500 MPa......Page 155
Diffusion Coefficient and Solubility......Page 156
Strength......Page 157
References......Page 158
1. Introduction......Page 159
2. The Electronic Structure of a-Si02......Page 160
3. Structure of Point Defects in a-Quartz......Page 162
Silicon Vacancies......Page 163
Interstitial Impurity Defects......Page 164
4. Line Defects in Quartz......Page 165
5. The Defect Chemistry of Pure Quartz......Page 166
6. The H20-Si02 System in the Solid State......Page 168
Deformation Rate Controlled by the Climb of Dislocations......Page 173
8. Summary and Conclusions......Page 174
References......Page 175
1. Introduction......Page 179
2.2. Buffering......Page 180
3.1. Olivine......Page 181
3.2. Forsterite......Page 185
4.1. Olivine......Page 186
4.2. Forsterite......Page 189
6. Defect Equilibration Time......Page 190
References......Page 191
Experimental Details......Page 193
Results......Page 194
Discussion......Page 198
References......Page 200
Experimental Method......Page 202
Theory and Results......Page 209
Discussion......Page 212
References......Page 217
Experimental Conditions......Page 219
Optical Microscopy......Page 220
Precipitate Size and Distribution......Page 222
Chemical Compositions of the Metallic Phase and Matrix......Page 223
Modeling the Reduction Process......Page 224
Incubation Period......Page 225
Formation and Initial Propagation of Reaction Zone......Page 226
Pore Formation and Surface Rumpling......Page 227
Regime A:......Page 228
Regime C:......Page 229
Dislocation Pipe Diffusion......Page 230
Dislocation-Assisted Diffusion......Page 231
References......Page 232
Introduction......Page 234
Precipitation Reactions......Page 236
Other Evidence......Page 238
Conclusions......Page 239
References......Page 240