Poster Presentation 24th Australian Conference on Microscopy and Microanalysis 2016

Integrated study of EBSD, NanoSIMS and synchrotron XFM mapping of auriferous arsenopyrite (FeAsS) (#225)

Denis Fougerouse 1 , Steven Micklethwaite 2 , Angela Halfpenny 3 , Matt Kilburn 4 , Loiuse Fisher 5 , Paul Gaugliardo 4
  1. Centre for Exploration targeting, The University of Western Australia, Crawley, WA, Australia
  2. School of Earth, Atmosphere & Environment, Monash University, Melbourne, Vic, Australia
  3. Microscopy & Microanalysis Facility, John de Later Centre, Curtin University, Perth, WA, Australia
  4. Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, WA, Australia
  5. CSIRO Mineral Resources Flagship, Bentley, WA, Australia

Arsenopyrite (FeAsS) is a strategic gold-bearing ore mineral found in many gold deposits. The primary distribution and subsequent redistribution of the gold in such minerals is critical in understanding the formation and evolution of ore deposits. However, the distribution of gold and the mechanisms for how gold may be naturally extracted from minerals are still poorly understood. To address this lack of understanding, arsenopyrite ores from the giant Obuasi gold deposit (Ghana) have been studied using a novel combination of Electron Backscattered Diffraction (EBSD), High-resolution X-ray computed tomography, Secondary Ion probes (SIMS and NanoSIMS) and quantitative synchrotron X-ray Fluorescence Microscopy trace element mapping at the Australian Synchrotron. The workflow combining these different characterisation techniques allows the identification of the microstructural and microchemical evolution of the arsenopyrite, across different scales, and provides the key elements needed to understand the geological formation of the Obuasi gold deposit.