Magmatic sulfide deposits. Geology, geochemistry and exploration / Магматические сульфидные месторождения. Геология, геохимия и разработка

Magmatic Nickel-Copper-Platinum-group element sulfide deposits form as the result of the segregation and concentration of droplets of liquid sulfide from mafic or ultramafic magma, and the partitioning of chalcophile elements into these from the silicate magma.

The size of the deposits, their grades and ratios of economic metals are very variable. This is illustrated in Table 1.1, which summarizes data on tonnes ofresources + production, grades ofNi, Cu, Co and PGE, tonnes of contained metal, and value of the ore and of the individual metals. It is also illustrated in Fig. 1.1, which shows the percentages that Ni+Co, Cu and the PGE contribute to the value of many magmatic sulfide deposits/camps. <...>

1 Introduction 

1.1 Classification of Magmatic Sulfide Deposits 

1.2 Size and Composition ofDeposits 

1.3 General Considerations for the Genesis of the Deposits 

2 Theoretical considerations 

2.1 The solubility of su1fur in silicate melts 

2.1.1 Effect ofTemperature 

2.1.2 Effect of Pressure 

2.1.3 Influence of fe1sification of mafic/ultramafic magma 

2.1.4 Variation of Solubility of Sulfide During Fractional

Crystallization of a Layered Intrusion 

2.2 Partitioning of Chalcophile Metals between Sulfides and Silicate Melts 

2.2.1 Partitioning of nickel between sulfide and silicate liquids 

2.2.2 Partitioning ofNi between Olivine and sulfide liquid 

2.2.3 Partitioning ofPGE between Sulfide and Silicate Melts 

2.2.4 Effect ofratio ofmagma to sulfide 

2.3 Relevant Phase Equilibria 

2.3.1 The System Fe-S-O and its application to natural ore magmas 

2.3.2 Relevant Sulfide Systems 

2.4 Fractional crystallization of sulfide liquids 

2.4.1 Partition coefficient ofNi and Cu between mss and coexisting sulfide liquid 

2.4.2 Partition of noble metals 

2.4.3 Modeling of fractional crystallization of sulfide melts 

2.5 Extemal sources of sulfur 

3 Komatiite-Related Deposits 

3.1 Archean Komatiite-Related Deposits 

3.2.1 General information about Archean komatiites and associated mineralization 

3 .1.2 Deposits of the Wiluna-N orseman greenstone belt (Eastem

Goldfields, Western Australia) 

3.2 Early Proterozoic Komatiite-Related Deposits 

3.2.1 Deposits ofthe Cape Smith belt, Quebec, Canada 

3.2.2 Deposits ofthe Thompson Nickel Belt, Manitoba, Canada 

4 Ore deposits associated with flood basalt volcanism 

4.1 Ni-Cu-PGE deposits ofthe Noril'sk region, Siberia 

4.1.1 Geological Setting 

4.1.2 Permo-Triassic Volcanism 

4.1.3 Ore-Bearing and Related Intrusions 

4.1.4 Ore Deposits 

4.1.5 Summary ofthe model for the Noril'sk Ore Camp

4.2 Mineralization ofthe Lake Superior Region (North America) 

4.2.2 Duluth Complex 

4.2.3 Crystal Lake Gabbro 

4.2.4 Conclusions arising from Keweenawan Mineralization 

4.3 Deposits Associated with the Karoo Flood Basalt of Southem Africa 

4.3.1 General information 

4.3.2 Geology of the Insizwa Complex 

4.3.3 The Insizwa intrusion at Waterfall Gorge 

4.3.4 Petrography 

4.3.5 Mineralogy and Mineral Chemistry 

4.3.6 Evidence relating to Contamination and Ore Genesis at Waterfall Gorge 

4.3.7 Conclusions for the Insizwa Complex 

4.4 Flood Basalt Provinces as Environments for Mineralization 

5 Deposits of the Pechenga area, Russia 

5.1 Regional geology 

5.2 Geology ofthe Pechenga Structure 

5.3 Geochemistry ofFerropicritic Rocks 

5.4 Comagmatic Relationship between the Ferropicritic V oleanie rocks and the Ore-bearing Gabbro-wehrlite Intrusions 

5.5 Gabbro-wehrlite intrusions 

5.6 Magmatic Sulfide Deposits 

5 .6.1 General information 

5.6.2 Sulfur isotopic Composition ofOres and Country rocks 

5.6.3 Ni, Cu and PGE variations and Re-Os isotopic systematics

ofthe Ores and Ore-bearing Intrusions 

5.7 A Genetic Model for the Pechenga Ores 

6 Voisey's Bay and other deposits, Labrador, Canada 

6.1 History of discovery and exploration 

6.2 General geology 

6.3 Geology ofthe Voisey's Bay intrusion 

6.4 Petrography of Rock Types 

6.5 Olivine and Plagiodase Compositions 

6.5.1 Stratigraphie Variation in Olivine and Plagiodase Composition 

6.5.2 Ni and Fo content ofOlivine in Different Rock Sequences

6.6 Geochemistry ofVoisey's Bay Rocks 

6.6.1 Major Elements 

6.6.2 Trace Elements 

6.6.3 Isotope Geochemistry 

6.7 Mineralization within the Voisey's Bay Intrusion 

6.7.1 Types ofMineralization 

6. 7.2 The Ni and Cu content of Sulfide Mineralization from Different Mineralized Environments 

6.7.3 Noble metal content ofSulfides from Different Mineralised Environments 

6. 7.4 Sulfur Isotopes 

6.8 Geological Model 

6.9 Condusions as to the genesis ofthe Voisey's Bay Deposit 

6.10 Other deposits associated with the Nain Plutonic Suite 

6.10.1 Troctolite/gabbro related 

6.1 0.2 Mineralization associated with Anorthosites 

6.10.3 Mineralization associated with Ferrodiorites 

6.1 0.4 Lessons to be learned from the Minera1ization associated with the Nain Plutonic Suite 

7 The Jinchuan deposit, China 

7.1 Geology ofthe deposit 

7.2 Petrography 

7.3 Geochemistry Of The Intrusive Rocks 

7.3.1 Majorelements 

7.3.2 Trace elements 

7.4 Olivine Compositions 

7.5 Petrogenesis 

7.5.1 MgO/(MgO+FeO) ratio ofthe parental magma 

7.5.2 Composition ofthe parental magma 

7.5.3 Constraints on Magma Emplacement and Differentiation 

7.6 Sulfide Mineralization 

7.6.1 Geology ofthe Ore Bodies 

7.6.2 Geochemistry of Sulfide Ores 

7. 7 MetaBogenesis 

7.8 Genetic model for the Jinchuan deposit

8 Deposits of the Sudbury Camp, Ontario, Canada 

8.1 Some History 

8.2 Geology 

8.2.1 Regional Setting 

8.2.2 Geology of the Sudbury Structure 

8.2.3 Evidence for Explosive Nature of the Sudbury Structure 

8.3 Units ofthe Sudbury Igneous Complex 

8.3.1 MainMass 

8.3.2 Sublayer and its Inclusions 

8.3.3 Offsets 

8.4 Geochemistry ofthe Sudbury Igneous Complex 

8.4.1 Major Elements 

8.4.2 Trace Elements 

8.4.3 Isotopes 

8.5 Sulfide Ore Deposits 

8.6 Metal contents of different Ore Deposit Types 

8.7 Ore mineralogy 

8.8 Relationship of Ore Deposits to the Rocks of the Complex 

8.9 Discussion ofthe Origin ofthe SIC and its Mineralization 

8.9.1 Impact Events 

8.9.2 Development ofthe SIC and its Associated Mineralization

8.10 Conclusions 

9 Platin um group element (PGE) deposits 

9.1 PGE in Mantle-derived Rocksand Mafic/Ultramafic Lavas 

9.2 Mechanisms for the Concentration of PGE 

9.3 Classification ofPGE deposits on their Morphology and composition 

9.4 Deposits in layered intrusions 

9.4.1 Bushveld Complex 

9 .4.2 Stillwater Complex 

9.4.3 Great Dyke of Zimbabwe 

9.4.4 Munni Munni Complex, Western Australia 

9.4.5 Layered intrusions ofNorthem Finland 

9.4.6 Intrusions of Sudbury area in Central Ontario, Canada 

9 .4. 7 Intrusions in East Greenland 

9.4.8 The Sonju Lake Intrusion, Duluth Complex 

9.4.9 Genetic Models for Deposits in Layered Intrusions 

9.5 Non-stratabound Deposits 

9.5.1 Lac des lies PGE-bearing Complex 

9.5.2 The Longwoods Igneous Complex, New Zealand 

9.6 Deposits of the Urals Platinum Belt 

9.6.1 Nizhny Tagil type Mineralization 

9.6.2 Volkovsky and Baron type Deposits 

9.7 Summary 

10 Summary and use of genetic concepts in exploration 

10.1 Concepts used in Exploration for Ni-Cu Ores 

10.1.1. Genetic Concepts and their use 

10.1.2 Empirical Concepts and their use 

10.1.3 Teetonic Setting ofthe Deposits 

10.1.4 Methods for Determining whether a given Igneous Body has developed Immiscible Sulfide 

10.1.5 Use of Cu/Zr