The formation and distribution of orogenic gold deposits
Person photo Dr Iain Pitcairn
Department of Geological Sciences

Funding source: Swedish Research Council - Vetenskapsr├ądet (VR)
Period: 1/1/08 - 1/1/11
Funding: 810000 SEK
Orogenic gold deposits have provided over 25% of global gold production but their genesis is poorly understood. Crucially, the sources of metals and fluids required to form these deposits are unclear. Our innovative recent study of the Otago and Alpine Schists, New Zealand, has identified the sources of metals and fluids, and the processes that control chemical transport in this area. Gold, Ag, As, Cd, Hg, Mo, N, Sb, W and water are significantly depleted from mid to high metamorphic grade Otago and Alpine Schists. These elements are enriched in the Otago ore deposits, and the depleted rocks represent the source of metals and fluids responsible for mineralisation. The Otago study has identified a set of chemical characteristics explaining ore genesis in Otago, that can be tested in other orogenic gold terranes. I will test the “Otago Model” in two contrasting orogenic terranes, the Dalradian of Scotland which contains very few orogenic gold deposits, and the Meguma Terrane of Nova Scotia, Canada that is abundantly mineralised. This comparison will identify the factors that control distribution of orogenic gold deposits, and determine why some metamorphic belts are heavily mineralised whereas others contain no orogenic gold deposits. Understanding the factors that control their distribution will aid development of more efficient exploration models. The project will also further understanding of fluid flow and chemical transport during metamorphism and orogenesis.
Research fields (1)
Geological Sciences