Wed 10th October @ noon, Rm 312.222

Abstract:

Magmatic sulfides hosted by mafic/ultramafic rocks are the largest resource of Ni and platinum group elements (PGE) on the planet. The genesis of these deposits by magmatic processes of sulfide saturation, enrichment and fractionation are well constrained. However, there are some Ni and PGE deposits that occur as hydrothermal deposits. These have puzzled economic geologists for years due to the largely immobile behaviour of Ni and PGE in hydrothermal fluids and most have loosely assumed a connection with magmatic sulfides, but that link is, as yet, unproven. By using Zeiss’ automated mineralogy to fully quantify a suite of samples that represent the alteration and destruction of magmatic sulfides under specific geologic conditions, it is apparent that this process liberates significant Ni, Cu, Fe, S and Pd to a fluid phase, such that it becomes a viable source of these metals into hydrothermal fluids, and whilst causing the death of the magmatic ore deposit, it has the potential to rise again and become one of these enigmatic hydrothermal Ni and PGE deposits.

Short bio:

Dr David Holwell is an Associate Professor working as an economic geologists at the University of Leicester in the UK. He received a BSc (Hons) in Geology at Durham University and a Masters in Mining Geology from the Camborne School of Mines. His did his PhD at Cardiff University on the world class PGE deposit of the Platreef in South Africa. He has worked for SRK Exploration as a consultant exploration geologist and his research work focusses on the nature and genesis of precious and base metal ore deposits, helping to develop better exploration models. Most recently, this work has expanded into the field of technology metals, including major UK-government grants for work on tellurium and selenium; metals essential for the solar industry, and resources in demand for the growing electric car markets.