Erin Thompson, Postgraduate Researcher

Primary controls on the emplacement of mineralised magmatic units in the northern Bushveld Complex

Erin ThompsonContact Details

  • Email: et201@le.ac.uk
  • Room: G23, Bennett Building
  • Supervisors: Dr Dave Holwell (University of Leicester) Dr Marc Reichow (University of Leicester), Prof Tom Blenkinsopp (Cardiff University), Dr Iain McDonald (Cardiff University), Dr Hannah Hughes (Camborne School of Mines) and Andy Lloyd (Anglo American)

Research Theme

Solid Earth

Project Description

The Northern Limb of the Bushveld Complex, South Africa is host to the world’s largest resource of platinum-group elements (PGE), along with significant nickel, copper and cobalt in a complex magmatic sulfide ore deposit. All of these resources are linked with environmentally-friendly technologies and energy usages in the automotive industry, with the PGE being essential components in catalytic converters (including Pd which has more than tripled in price in the past five years), and Ni, Co and Cu critical metals in Electric Vehicle batteries. As such, the northern limb of the Bushveld is likely going to play a large part in the switch to cleaner automotive technology.

The major deposit in the Critical Zone of the northern Bushveld (commonly known as the ‘Platreef’) rests directly on variable basement of Archaean and Paleoproterozoic units at surface. Down dip, it overlies Bushveld Complex Lower Zone rocks; themselves prospective for base metal sulfide mineralisation. The stratigraphy, structure, mineralization styles and metal budgets of the Northern Limb of the Bushveld Complex show important differences to the other limbs of the complex. The underlying causes behind these differences are poorly understood and no geological model exists to investigate them on anything more than a local scale.

This research aims to tackle questions surrounding the controls on the emplacement of the various magmatic units, which appear to have their own, variable metal budgets and thicknesses. This focusses on processes that occur prior to and during emplacement and are critical to understanding the genetic and exploration models. The project is in partnership with Anglo American, who have been mining the Platreef via surface methods since the 1990s, and now operate the world’s largest PGE surface mining operation at the Mogalakwena Mine. Whilst the near-surface resources are reasonably well characterised, the down dip potential and extension of resources is known, but has had no research work completed on it thus far.

Research Questions

  • How did the pre-existing basement architecture and structure control the emplacement, thickness and grade of the northern limb magmas.
  • Which direction did the (potentially) sulphide-laden magmas move? Where is the feeder? Can we vector towards higher tenors and possibly more massive sulfide in feeder conduits?
  • Is the Lower Zone emplaced entirely before the Critical Zone, or is the Critical Zone a differentiated continuum/mixing zone of residual Lower Zone magma?
  • Which Lower Zone bodies are sources of viable Ni-Co-Cu-sulfides?
  • Were the magmas emplaced with a pre-enriched cargo of base and precious metals, and if so, where did the key processes of sulfide saturation and metal enrichment happen?
  • Are Northern Limb magmas inherently more Pd and Au enriched than the rest of the Bushveld?

Further links

Twitter: @erinthompson21

Linkedin Erin Thompson

 

 

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