PhD student
Centre for Exploration Targeting (CET)
Contact details
Address
Robert Street Building, Rm 207
Centre for Exploration Targeting (CET)
The University of Western Australia (M006)
35 Stirling Highway
CRAWLEY WA 6009
Australia
Phone
+61 8 6488 1809
Email
20876767@student.uwa.edu.au
Hydrothermal haloes around magmatic nickel sulphide deposits. Magmatic nickel sulfide deposits are composed of small, generally deep seated and very valuable ore bodies, hosted by large mafic to ultramafic units. While some of these deposits are geophysical Electro-Magnetic (EM) targets, many are not, and in many cases, near misses (e.g. beyond the range of down-hole EM) are effectively complete misses. Moreover, primary magmatic chemical haloes in host rocks are effective in some environments but not others, and are absent from many deposits. For the mining exploration industry, magmatic nickel sulphide deposits represent needles in hay stacks! The discovery rate of new deposits of this style has slowed dramatically since the initial surge of exploration success between 1966 and 1973, especially in mature mining camp such as the Eastern Goldfields. This decrease highlights the need for a new approach to help exploration. This project intends to tackle the problem from a different angle.
The genesis of magmatic nickel sulphide deposits has been extensively studied over the years and the wide knowledge acquired about primary magmatic processes has been extensively applied to exploration targeting. But the study of secondary processes affecting nickel sulphide deposits, especially post magmatic circulation of hydrothermal and metamorphic fluids, received little attention within the research community. The circulation of hot hydrothermal fluids, first through a nickel sulphide deposit and then along major structures and through the surrounding rocks must have modified the rock composition. The impact of hydrothermal fluids on the composition of rocks surrounding nickel sulphide deposits is not understood. Yet it has the potential to result in large halos, whose recognition could revolutionise exploration for magmatic nickel deposits. This project intends to address this knowledge gap.
Unlike previous projects which have focused on primary magmatic processes: dynamic, shape and geochemistry of lava flows, this project will focus on secondary, post magmatic transformation of the geochemistry and mineralogy of magmatic nickel sulphide systems. Through an empirical study based on observations, we will determine the nature and the 3D geometry of the footprint created by remobilisation of base metals, platinum-group elements and gold by hydrothermal fluids.
This project is part of the M413 project, sponsored by MERIWA and its significance is also highlighted by the ARC linkage fund This linkage will provide experimental results to answer the following question: “to which degree base and precious metals such as the platinum group elements (PGE), which are generally associated with nickel sulphides, may have been mobilised by hydrothermal fluids.” The key elements missing from our understanding of the size and nature of hydrothermal footprints surrounding magmatic nickel sulphide deposits revolve around the poorly constrained behaviour of critical elements such as nickel, cobalt and the PGE in hydrothermal solution. This question will be placed at the heart of the research strategy of the ARC linkage project undertaken by the University of Adelaide and the results will underpin any working hypothesis which will be used for our project.
Undiscovered deposits are highly likely to exist at depth, even in mature well-explored terranes, but are likely to be deformed, altered and offset from readily detectable magnetic host rock units. Such targets may be highly attractive, high-grade deposits worth billions of dollars. The ultimate goal of this proposal is to enlarge the detectable footprint of these targets.