Introduction to Ore-Forming Processes

Introduction to Ore-Forming Processes......Page 5
Contents......Page 7
Preface......Page 9
INTRODUCTION AND AIMS......Page 11
A CLASSIFICATION SCHEME FOR ORE DEPOSITS......Page 12
WHAT MAKES A VIABLE MINERAL DEPOSIT?......Page 14
SOME USEFUL DEFINITIONS AND COMPILATIONS......Page 16
NATURAL RESOURCES, SUSTAINABILITY, AND ENVIRONMENTAL RESPONSIBILITY......Page 21
Summary and futher reading......Page 25
Part 1 Igneous Processes......Page 27
1.1 INTRODUCTION......Page 29
1.2 MAGMAS AND METALLOGENY......Page 30
1.3 WHY ARE SOME MAGMAS MORE FERTILE THAN OTHERS? THE “INHERITANCE FACTOR”......Page 38
1.4 PARTIAL MELTING AND CRYSTAL FRACTIONATION AS ORE-FORMING PROCESSES......Page 47
1.5 LIQUID IMMISCIBILITY AS AN ORE-FORMING PROCESS......Page 64
1.6 A MORE DETAILED CONSIDERATION OF MINERALIZATION PROCESSES IN MAFIC MAGMAS......Page 67
1.7 A MODEL FOR MINERALIZATION IN LAYERED MAFIC INTRUSIONS......Page 81
Summary and further reading......Page 84
2.1 INTRODUCTION......Page 85
2.2 SOME PHYSICAL AND CHEMICAL PROPERTIES OF WATER......Page 86
2.3 FORMATION OF A MAGMATIC AQUEOUS PHASE......Page 89
2.4 THE COMPOSITION AND CHARACTERISTICS OF MAGMATIC-HYDROTHERMAL SOLUTIONS......Page 95
2.5 A NOTE ON PEGMATITES AND THEIR SIGNIFICANCE TO GRANITE-RELATED ORE-FORMING PROCESSES......Page 103
2.6 FLUID–MELT TRACE ELEMENT PARTITIONING......Page 106
2.7 WATER CONTENT AND DEPTH OF EMPLACEMENT OF GRANITES – RELATIONSHIPS TO ORE-FORMING PROCESSES......Page 111
2.8 MODELS FOR THE FORMATION OF PORPHYRY-TYPE CU, MO, AND W DEPOSITS......Page 116
2.9 FLUID FLOW IN AND AROUND GRANITE PLUTONS......Page 118
2.10 SKARN DEPOSITS......Page 123
2.11 NEAR-SURFACE MAGMATIC-HYDROTHERMAL PROCESSES – THE “EPITHERMAL” FAMILY OF AU–AG–(CU) DEPOSITS......Page 127
2.12 THE ROLE OF HYDROTHERMAL FLUIDS IN MINERALIZED MAFIC ROCKS......Page 132
Summary and further reading......Page 135
Part 2 Hydrothermal Processes......Page 137
3.1 INTRODUCTION......Page 139
3.2 OTHER FLUIDS IN THE EARTH’S CRUST AND THEIR ORIGINS......Page 140
3.3 THE MOVEMENT OF HYDROTHERMAL FLUIDS IN THE EARTH’S CRUST......Page 148
3.4 FURTHER FACTORS AFFECTING METAL SOLUBILITY......Page 157
3.5 PRECIPITATION MECHANISMS FOR METALS IN SOLUTION......Page 163
3.6 MORE ON FLUID/ROCK INTERACTION – AN INTRODUCTION TO HYDROTHERMAL ALTERATION......Page 176
3.7 METAL ZONING AND PARAGENETIC SEQUENCE......Page 184
3.8 MODERN ANALOGUES OF ORE-FORMING PROCESSES – THE VMS–SEDEX CONTINUUM......Page 187
3.9 MINERAL DEPOSITS ASSOCIATED WITH AQUEO-CARBONIC METAMORPHIC FLUIDS......Page 199
3.10 ORE DEPOSITS ASSOCIATED WITH CONNATE FLUIDS......Page 207
3.11 ORE DEPOSITS ASSOCIATED WITH NEAR SURFACE METEORIC FLUIDS (GROUNDWATER)......Page 219
Summary and further reading......Page 224
Part 3 Sedimentary/Surficial Processes......Page 227
4.1 INTRODUCTION......Page 229
4.2 PRINCIPLES OF CHEMICAL WEATHERING......Page 230
4.3 LATERITIC DEPOSITS......Page 233
4.4 CLAY DEPOSITS......Page 243
4.5 CALCRETE-HOSTED DEPOSITS......Page 245
4.6 SUPERGENE ENRICHMENT OF CU AND OTHER METALS IN NEAR SURFACE DEPOSITS......Page 248
Summary and further reading......Page 255
5.1 INTRODUCTION......Page 256
5.2 CLASTIC SEDIMENTATION AND HEAVY MINERAL CONCENTRATION – PLACER DEPOSITS......Page 257
5.3 CHEMICAL SEDIMENTATION – BANDED IRON-FORMATIONS, PHOSPHORITES, AND EVAPORITES......Page 276
5.4 FOSSIL FUELS – OIL/GAS FORMATION AND COALIFICATION......Page 297
Summary and further reading......Page 317
6.1 INTRODUCTION......Page 321
6.3 CONTINENTAL GROWTH RATES......Page 322
6.4 CRUSTAL EVOLUTION AND METALLOGENESIS......Page 325
6.5 METALLOGENY THROUGH TIME......Page 329
6.6 PLATE TECTONICS AND ORE DEPOSITS – A SUMMARY......Page 349
Summary and further reading......Page 353
References......Page 355
Index......Page 378