Hydrothermal Mineral Deposits

I Introduction.- I Nature and Types of Hydrothermal Solutions and Systems.- 1 Water and Solutions.- 1.1 Introduction.- 1.2 Water: Its Origin and Significance.- 1.2.1 Planetary Evolution and the Origin of Water.- 1.2.2 Water — Past and Present.- 1.2.3 Water in Subduction Zones.- 1.2.4 Water in the Crust.- 1.3 Solutions.- 1.4 Solubility and Boiling.- 1.5 Acid-Base Nomenclature.- 1.6 Structure of Water — Hydrolysis and Hydration.- 1.7 Redox Potential (Eh).- 1.8 Chemical Potential, Chemical Activity and Fugacity.- References.- 2 Hydrothermal Solutions.- 2.1 Introduction.- 2.2 Water of Hydrothermal Solutions.- 2.3 Oxygen and Hydrogen Isotope Systematics of Hydrothermal Fluids.- 2.4 Fluid Inclusions.- 2.5 Dissolved Constituents and Metals Partitioning into Hydrothermal Solutions.- 2.5.1 Partitioning of Metallic Elements into Hydrothermal Solutions.- 2.6 Metal Transport.- 2.6.1 Complex Ions and Ligands.- 2.6.2 Complex Ions in Hydrothermal Solutions.- 2.7 Metal Deposition.- References.- 3 Hydrothermal Systems.- 3.1 Introduction.- 3.2 Definition and Types.- 3.3 Magmatic Hydrothermal Systems Related to Shallow and Deep-Seated Plutonism.- 3.4 Magmatic-Meteoric Hydrothermal Systems, Related to Volcano-Plutonic and Volcanic Complexes.- 3.4.1 Magmatic Hydrothermal Systems.- 3.4.2 Predominantly Meteoric Hydrothermal (Geothermal) Systems.- 3.4.3 Hot Water-Dominated and Vapour-Dominated Hydrothermal Systems.- 3.4.4 Hot Springs, Mud Pools, Geysers, Crater Lakes and Fumaroles.- 3.5 Sub-Sea-Floor Hydrothermal Systems: Spreading Centres and Island Arcs.- 3.5.1 Hydrothermal Systems in Spreading Centres.- 3.5.2 Hydrothermal Systems in Submarine Volcanic Centres.- 3.6 Rift-Associated Hydrothermal Systems in Sedimentary Basins.- 3.6.1 Hydrothermal Systems.- 3.6.2 Hydrothermal Systems in Modern Rift Settings.- 3.7 Hydrothermal Systems of Metamorphic and Crustal Origin.- 3.7.1 Metamorphism, Metasomatism, Dewatering of Rock Sequences and Fluid Generation.- 3.7.2 Fluid Pressure, Metamorphic Porosity, Impermeable Barriers and Hydraulic Fracturing.- 3.7.3 Metamorphic Hydrothermal Systems.- 3.7.4 Fluid Paths: Faults, Shear Zones and Thrust Faults.- 3.7.5 Fluids in Subduction Zones.- References.- 4 Hydrothermal Alteration.- 4.1 Introduction.- 4.2 Hydrogen Ion Metasomatism and Base Exchange.- 4.2.1 Chemical Processes Related to Hydrogen Ion Metasomatism.- 4.3 Styles and Types of Hydrothermal Alteration.- 4.3.1 Styles of Alteration.- 4.3.2 Types of Alteration.- 4.3.3 Other Types of Alteration.- 4.4 Quantification and Monitoring of Hydrothermal Alteration Processes — Data Presentation.- 4.4.1 Rare Earths Elements in Hydrothermal Alteration Processes.- 4.5 Oxygen and Hydrogen Isotope Systematics.- 4.6 Metamorphism of Hydrothermally Altered Rocks.- 4.7 Detection of Hydrothermal Alteration by Spectral Remote Sensing.- References.- II Crustal Evolution, Global Tectonics, Hydrothermal Mineral Deposits and Mineral Exploration — Geotectonic and Metallogenic Analysis of Orogenic Belts.- 5 Crustal Evolution, Global Tectonics and Mineral Deposits.- 5.1 Introduction.- 5.2 Tectonic Phases in the Earth’s Geological Evolution and Related Metallogeny.- 5.2.1 The Archean Eon: Phase of Microplate Tectonics.- 5.2.2 The Proterozoic Eon: Phase of Intraplate Tectonics.- 5.2.3 The Phanerozoic Eon: Phase of Macroplate Tectonics, Sea Floor Spreading and Continental Drift.- 5.2.4 Conclusions.- References.- 6 Geological Processes and Hydrothermal Mineralisation in Plate Tectonic Settings — Mineral Exploration.- 6.1 Introduction.- 6.2 Extensional Plate Tectonics.- 6.2.1 Mid-Ocean Spreading Centres.- 6.2.2 Intracontinental Rifts.- 6.2.3 Passive Continental Margins and Interior Basins.- 6.3 Compressional Plate Tectonics.- 6.3.1 Subduction-Related Settings.- 6.3.2 Collision-Related Settings.- 6.4 Transform Fault Tectonics.- References.- 7 Geotectonic and Metallogenic Analysis of Orogenic Belts.- 7.1 Introduction.- 7.2 The Pan-African Orogenic Belts of Africa.- 7.2.1 The Arabian-Nubian Shield.- 7.2.2 The Damara Orogen, Namibia.- 7.2.3 The Lufillian Fold Belt.- 7.3 Metallogenic Epochs and Geotectonic Environments of Hydrothermal Mineral Deposits of the Orogenic Belts in New Zealand.- 7.3.1 Geotectonic Settings of the Tuhuan Orogeny and Related Hydrothermal Mineralisation.- 7.3.2 Geotectonic Settings of the Rangitata Orogeny and Related Hydrothermal Mineralisation.- 7.3.3 Geotectonic Settings of the Kaikoura Orogeny and Related Hydrothermal Mineralisation.- References.- III Hydrothermal Processes and Activities — Related Mineral Deposits.- 8 Alkali Metasomatism and Related Mineral Deposits.- 8.1 Introduction.- 8.2 Alkali Metasomatism in Continental Igneous Systems.- 8.2.1 Role of Volatiles in Granitic Magmas.- 8.2.2 Textural Features.- 8.2.3 Sodic Metasomatism and Albitites.- 8.2.4 Potassic Metasomatism and Microclinites.- 8.3 Alkali Metasomatism in Anorogenic Ring-Type Complexes.- 8.3.1 Fenites.- 8.4 Mineralisation Related to Alkali Metasomatism.- 8.4.1 Mineralisation in Ring Complexes of the Ijolite-Carbonatite Association.- 8.4.2 Mineralisation in Ring Complexes of the Alkaline Granite Association.- 8.4.3 Mineralisation Related to Alkali Metasomatism of Pegmatites.- References.- 9 Greisen Systems.- 9.1 Introduction.- 9.2 Greisenisation Processes.- 9.3 Geochemistry.- 9.4 Greisen-Related Mineral Deposits.- 9.4.1 Sn and W Geochemistry in the Greisen Environment — Deposition of Cassisterite and Wolframite.- 9.4.2 Sn Deposits Associated with the Acid Phase of the Bushveld Igneous Complex, South Africa.- 9.4.3 Sn-W Mineralisation at Brandberg West, Damara Orogen, Namibia.- 9.4.4 Endo- and Exogreisen Sn Mineralisation at Mount Bischoff, Tasmania.- 9.4.5 The Hercynian Sn-W Deposits of Southwest England, Cornwall and Portugal.- References.- 10 Porphyry Systems and Skarns.- 10.1 Introduction.- 10.2 Tectonic Settings.- 10.3 Classification of Porphyry Systems.- 10.4 Hydrothermal Alteration and Mineralisation.- 10.4.1 Lowell-Guilbert Model.- 10.4.2 Diorite Model.- 10.4.3 Alteration-Mineralisation of Carbonate Wall Rocks (Skarns).- 10.5 Mineral Deposits of Porphyry Systems.- 10.5.1 Panguna and Ok Tedi Porphyry Cu-Au Deposits.- 10.5.2 Porphyry Cu-Mo Deposits in Chile.- 10.5.3 Porphyry Mo Deposits of the Colorado Mineral Belt.- 10.5.4 Porphyry Mo Mineralisation in the Oslo Graben, Norway.- 10.5.5 Skarn Deposits in the Western USA.- 10.5.6 Other Types of Skarn Deposits.- 10.5.7 Porphyry Sn Deposits in Bolivia.- References.- 11 Fossil and Active Geothermal Systems — Epithermal Base and Precious Metal Mineralisation (Including Kuroko-Type Deposits).- 11.1 Introduction.- 11.2 General Characteristics of Epithermal Systems.- 11.2.1 Main Types of Epithermal Deposits.- 11.3 Volcanic-Hosted Epithermal Deposit Types.- 11.3.1 Epithermal Systems of Submerged Volcanic Structures.- 11.3.2 Hydrothermal Alteration.- 11.3.3 Mineral and Metal Zoning.- 11.4 Transport and Deposition of Precious Metals in Epithermal Systems.- 11.4.1 Boiling Depths and Metal Zoning.- 11.5 Active Geothermal Fields.- 11.5.1 Geothermal Systems of the Taupo Volcanic Zone, New Zealand.- 11.5.2 Salton Sea, California, USA.- 11.6 Volcanic-Hosted Epithermal Mineral Deposits.- 11.6.1 Hauraki Goldfields, Coromandel Peninsula, New Zealand.- 11.6.2 Epithermal Au in Lihir Island, Papua New Guinea.- 11.7 Sediment-Hosted Epithermal Deposits.- 11.7.1 Mineral Belts and Deposit Types of Nevada, USA.- 11.7.2 Nature of Fluids and Ore Genesis.- 11.8 Kuroko-Type Mineral Deposits.- 11.8.1 Kuroko Deposits.- 11.8.2 Precambrian Volcanogenic Massive Sulphide Deposits.- References.- 12 Hydrothermal Processes in Oceanic Crust and Related Mineral Deposits.- 12.1 Introduction.- 12.2 Physiography of the Ocean Floor.- 12.2.1 Mid-Ocean Ridges.- 12.2.2 Transform Faults and Fracture Zones.- 12.2.3 Seamounts and Volcanic Chains.- 12.3 Birth, Life and Death of an Ocean Basin.- 12.4 Oceanic Lithosphere and Ophiolites.- 12.5 Heat Flow, Oceanic Crust Metamorphism and the Nature of Related Hydrothermal Solutions.- 12.5.1 Heat Flow and Oceanic Crust Metamorphism.- 12.5.2 Nature and Composition of the Hydrothermal Solutions.- 12.6 Tectonic Settings, Sub-Sea-Floor Hydrothermal Processes, Hot Springs and Their Mineral Deposits.- 12.6.1 Tectonic Settings.- 12.6.2 Hydrothermal Processes and Types of Sulphide Deposits.- 12.6.3 Sub-Sea-Floor Hydrothermal Mineral Deposits.- 12.7 Oceanic Crust-Related Hydrothermal Mineral Deposits.- 12.7.1 Massive Sulphide Deposits of the Samail Ophiolite, Oman.- 12.7.2 The Cu Deposits of Cyprus Island.- 12.7.3 The Cu Deposits of the Matchless Amphibolite Belt, Namibia.- References.- 13 Hydrothermal Mineral Deposits of Continental Rift Environments.- 13.1 Introduction.- 13.2 Continental Rifting.- 13.2.1 Geophysical Signatures of Continental Rifts.- 13.3 Magmatism and Metamorphism Associated with Rifting.- 13.3.1 The Nature of Igneous Activity in Rift Systems.- 13.3.2 Metamorphism in Continental Rifts.- 13.4 Basin Formation and Volcano-Sedimentary Sequences in Continental Rifts.- 13.4.1 The Stratigraphic Record of Proterozoic Basins in South Africa.- 13.4.2 The Stratigraphic Record of Aulacogens.- 13.4.3 The East African Rift System.- 13.4.4 The Rio Grande Rift (USA).- 13.5 Continental Rifting in Space and Time — Hydrothermal Mineral Deposits.- 13.5.1 Early Stages of Continental Rifting.- 13.5.2 Aulacogens and Troughs — Intermediate Stages of Continental Rifting.- 13.5.3 Advanced Stages of Rifting.- 13.6 Hydrothermal Mineral Deposits in Incipient Rifts.- 13.6.1 The Messina Cu Deposits, South Africa.- 13.6.2 Olympic Dam (Roxby Downs), South Australia.- 13.6.3 Hydrothermal Activity in the Tanganyika Trough, East African Rift System.- 13.7 Hydrothermal Mineral Deposits in Aulacogens and Troughs at Intermediate Stages of Rifting.- 13.7.1 McArthur River and Mt. Isa, Northern Australia.- 13.7.2 The Sediment-Hosted Exhalative Massive Sulphide Deposits in the Namaqualand Metamorphic Complex, South Africa.- 13.7.3 Stratabound Cu-Ag Deposits of the Irumide Belt in Southern Africa.- 13.7.4 The Zambian Copperbelt.- 13.7.5 Stratiform and Stratabound Cu Deposits of the Keweenawan Rift.- 13.8 Mineral Deposits Related to Advanced Stages of Rifting — the Red Sea Deeps.- 13.9 Banded Iron Formation (BIF) of Proterozoic Age.- 13.9.1 The Mineral Deposits of the Transvaal-Griqualand Basins.- References.- 14 Stratabound Carbonate-Hosted Base Metal Deposits.- 14.1 Introduction.- 14.2 Mississipi Valley-Type Deposits (MVT).- 14.2.1 The Viburnum Trend, USA.- 14.2.2 Pine Point, Canada.- 14.3 Alpine-Type Deposits.- 14.4 Irish-Type Deposits.- 14.4.1 Mineral Deposits.- 14.5 Models of Ore Genesis for the MVT, Alpine and Irish Types.- 14.5.1 Karsting.- 14.5.2 Nature and Temperature of Fluids, Source of Metals and Sulphur.- 14.6 The Carbonate-Hosted Pb-Zn-Cu-Ag and V Deposits of the Otavi Mountain Land, Namibia.- 14.6.1 Geology, Structure and Metamorphism.- 14.6.2 Mineralisation.- 14.6.3 Tsumeb.- 14.6.4 Kombat.- 14.6.5 Berg Aukas.- 14.6.6 Models of Ore Genesis.- References.- 15 Crustal Hydrothermal Fluids and Mesothermal Mineral Deposits.- 15.1 Introduction.- 15.2 Metamorphism and Fluid Generation.- 15.2.1 Metamorphic Devolitilisation Reactions.- 15.2.2 Fluid Transport and Migration.- 15.2.3 Shear Zones.- 15.2.4 Metamorphic Vein Systems and Vein Growth.- 15.2.5 Mass Transport and Movement of Metals.- 15.2.6 Au in Hydrothermal Fluids.- 15.2.7 Oxygen and Hydrogen Isotope Systematics.- 15.3 Tectonic Settings.- 15.4 Archean Mesothermal Deposits.- 15.4.1 The Archean Greenstone Belts.- 15.4.2 Metallogenesis.- 15.4.3 Theories on the Genesis of Archean Mesothermal Au Deposits.- 15.4.4 Mesothermal Au Deposits of the Barberton and Murchison Greenstone Belts, South Africa.- 15.4.5 The Golden Mile, Yilgarn Block, Western Australia.- 15.4.6 The Hemlo Au-Mo Deposit, Superior Province, Canada.- 15.5 Mesothermal Vein Deposits of Phanerozoic Age (Turbidite-Hosted Au).- 15.5.1 The Ballarat Slate Belt, Victoria, Australia.- 15.5.2 Hydrothermal Lode Systems of Otago-Marlborough and the Southern Alps, New Zealand.- 15.5.3 The Juneau Gold Belt, Southeast Alaska.- 15.6 Mineral Deposits Formed by Multistage Ore Genesis.- 15.6.1 Unconformity-Related U Deposits.- 15.6.2 Au Mineralisation in the Central Zone of the Damara Orogen, Namibia.- 15.6.3 The Possible Role of Metamorphic Fluids in the Origin of the Witwatersrand Goldfields, South Africa.- References.- Epilogue.