Controls on gold and silver volcanogenic sulphide deposits (84/P210) AMIRA report (CODES publication 10)

Statement of Aims To investigate the geological and geochemical controls on the distribution of precious metals within volcanic hosted massive sulphide deposits, with the objective of developing exploration models useful for the discovery of further precious metal-rich deposits. Progress in 1987 This is the third major report on the research results to emerge from this project, and marks the end of the second year of a three-year programme. The project is on schedule and, although we lost two of our team members to industry earlier in the year, progress in other areas has been excellent. Our progress since the previous meeting in November, 1986 is listed below (* items are reported in this volume). 1.* Studies on the Que River precious metal zone are virtually complete, and a final report is included herein. 2.* Gold distribution studies on the F-lens pyrrhotite, magnetite and tourmaline zones is complete. Mineralogical and geochemical work is continuing. 3.* Mapping, petrological and alteration studies on the Lake Selina system are complete. 4.* Whole rock geochemistry and R.E.E. research on the Mount Read Volcanics is near completion. 5.* Gold distribution and metal ratio studies on the Scuddles deposits, W.A., are complete. 6.* Structure and metal distribution studies at Balcooma, Qld, are complete. 7. Investigations on precious metal distribution in the Thalanga massive sulphide deposit, Qld, have commenced. 8. Literature research on gold in the Canadian Precambrian deposits is complete (see associated report). 9.* A discussion paper on the source and movement of gold in submarine volcanic environments has been completed. Parallel with this AMIRA research, an ARGS-funded study on the thermodynamics of gold transport and deposition mechanisms in VMS systems has been completed and is circulated as a separate report. In conclusion I would like to thank all members of the AMIRA team: Peter McGoldrick, Tony Crawford, David Huston, Khin Zaw, Steve Hunns, John Pernberton and Stewart Capp, in addition to June Pongratz and PhiI Robinson, all of whom have given their unfailing support to the project in 1987. Ross Large Project Leade