Geo-Platinum 87. Questo articolo non è disponibile.Geo-Platinum 87

The Geo-Platinum 87 Symposium, held at the Open University during April 1987, was designed as a forum for presentation of new research results on the occurrence, genesis, geochemistry, mineralogy and analysis of the platinum-group elements (PGE). With the support of the Open University and the Mineral Industry Research Organisation, the symposium was attended by 115 representatives of university departments, research institutions and members of the mining and mineral exploration industries. An introduction to the symposium was provided by two invited papers from C. J. Morrissey (Riofinex North) and C. R. N. Clark (Johnson Matthey) which were designed to give perspective to the goals of PGE research work. The first of these papers gave a provocative insight into the aims and objectives of an exploration manager, examining the influence of supply, demand and perceived world reserves on exploration strategy. The second invited paper gave a valuable view of the industrial uses, market trends and predicted changes in the commercial value of the platinum-group elements from the standpoint of a refining company and supplier. These invited papers are reproduced in this volume and are followed by twenty­ four full papers and twenty abstracts that reflect the wide range of research topics presented at the symposium.

Invited Papers.- 1. Exploration for Platinum: A Contemporary Viewpoint.- 2. The Platinum Market: Recent History and Future Developments.- Analytical Techniques.- 3. Evaluation of the Nickel Sulphide Bead Method of Fire-assay for the Platinum-Group Elements using Neutron Activation Analysis.- 4. Preconcentration of Precious Metals by Tellurium Sulphide Fire-assay Followed by Instrumental Neutron Activation Analysis.- 5. The Potential of Fire-assay and ICP-MS for the Determination of Platinum-Group Elements in Geological Materials (Abstract).- 6. ICP-AES Determination of Precious Metals in Difficult Materials (Abstract).- 7. New Detection Techniques for Locating Precious Metal Minerals by Beta Autoradiography: Preliminary Results for Rhodium and Silver Grains.- Theoretical and Experimental Studies.- 8. Solubility and Transport of Platinum-Group Elements in Hydro-thermal Solutions: Thermodynamic and Physical Chemical Constraints.- 9. New Mechanisms for the Mobilization of the Platinum-Group Elements in the Supergene Zone.- 10. Spinel Non-stoichiometry as the Explanation for Ni-, Cu- and PGE-enriched Sulphides in Chromitites.- 11. The Potential for Hydrothermal Platinum Deposits (Abstract).- Europe and North Africa.- 12. The Use of Mantle Normalization and Metal Ratios in Discriminating Between the Effects of Partial Melting, Crystal Fractionation and Sulphide Segregation on Platinum-Group Elements, Gold, Nickel and Copper: Examples from Norway.- 13. Noble Metal Geochemistry of Some Ni-Cu Deposits in the Sveco-norwegian and Caledonian Orogens in Norway.- 14. The Significance of Cumulus Chlorapatite and High-temperature Dashkesanite to the Genesis of PGE Mineralization in the Koitelainen and Keivitsa-Satovaara Complexes, Northern Finland (Abstract).- 15. The Shetland Ophiolite: Evidence for a Supra-subduction Zone Origin and Implications for Platinum-Group Element Mineralization (Abstract).- 16. Nickel-Copper and Precious Metal Mineralisation in the Caledonian Mafic and Ultramafic Intrusions of North-East Scotland (Abstract).- 17. Platinum-Group Element Analyses of Serpentinites in the Eastern Central Alps, from Davos (Switzerland) to the Valmalenco (Italy).- 18. Further Data on Platinum-Palladium Minerals from the Ivrea-Verbano Sulphide Deposits (Abstract).- 19. Platinum-Group Elements and Au Distribution in Ni Arsenide-Chromite Veins from the Rifo-Betic Lherzolite Massifs (Morocco-Spain).- 20. PGE Distribution in Some Ultramafic Rocks and Minerals from the Bou-Azzer Ophiolite Complex (Morocco).- North and South America.- 21. Exploration for Platinum-Group Elements in the Labrador Trough, Canada.- 22. Platinum-Group Element Mineralisation and the Relative Importance of Magmatic and Deuteric Processes: Field Evidence from the Lac des Iles Deposit, Ontario, Canada.- 23. Platinum-Group Mineral Precipitation from Fluids in Pegmatitic Gabbro: Two Duck Lake Intrusion, Coldwell Complex, Ontario, Canada (Abstract).- 24. Interelement Correlation, Stratigraphic Variation and Distribution of PGE in the Ultramafic Series of the Bird River Sill, Canada.- 25. Distribution of PGE in Sulphides of the Bay of Islands Ophiolite Complex, Newfoundland (Abstract).- 26. Chemical Evolution of Vapour During Crystallization of the Stillwater Complex (Abstract).- 27. The Distribution of the Platinum-Group Elements in the Palisades Sill, New Jersey and New York (Abstract).- 28. Platinum-Group Element Mineralogy of the Pole Corral Podiform Chromite Deposit, Rattlesnake Creek Terrane, Northern California (Abstract).- 29. PGE in Hawaiian Basalt: Implications of Hydrothermal Alteration on PGE Mobility in Volcanic Fluids (Abstract).- 30. Platinum-Group Minerals in Chromite-rich Horizons of the Niquelandia Complex (Central Goias, Brazil).- Equatorial and South Africa.- 31. Further Studies of the Development of Platinum-Group Minerals in the Laterites of the Freetown Layered Complex, Sierra Leone.- 32. The Geology and Economic Potential of the PGE-rich Main Sulphide Zone of the Great Dyke, Zimbabwe.- 33. PGE- and Au-distribution in Rift-related Volcanics, Sediments and Stratabound Cu/Ag Ores of Middle Proterozoic Age in Central SWA/Namibia.- 34. PGE in the 3·5 Ga Jamestown Ophiolite Complex, Barberton Greenstone Belt, with Implications for PGE Distribution in Simatic Lithosphere.- 35. Evidence for Fluid in the Footwall Beneath Potholes in the Merensky Reef of the Bushveld Complex.- 36. Geochemistry of the Mount Ayliff Intrusion and the Origin of Associated Sulphide Mineralization (Abstract).- 37. The Effects of Metasomatising Fluids on the PGE-content of the UG-1 Chromitite Layer (Abstract).- Far East.- 38. Platinum-Group Element Mineralization in the Ultramafic Sequence of the Acoje Ophiolite Block, Zambales, Philippines.- 39. Platinum-Group Element Abundance in Chromite Deposits of the Acoje Ophiolite Block, Zambales Ophiolite Complex, Philippines (Abstract).- 40. Platinum-Group Minerals in Ophiolitic Chromitites and Alluvial Placer Deposits, Meratus-Bobaris Area, Southeast Kalimantan.- 41. Platinum-Group Minerals in the Tiébaghi (New-Caledonia) and Vourinos (Greece) Ophiolites (Abstract).- Other Geochemical Studies.- 42. Platinum-Group Element Chemistry in Relation to the Behaviour of Individual PGEs in Primary and Secondary Geological Processes (Abstract).- 43. Gold and Iridium in Sulphides from Submarine Basalt Glasses (Abstract).- 44. PGE and other Trace Element Geochemistry at some Distinct Phanerozoic Stratigraphic Horizons (Abstract).- Index of Contributors.