Journal article
Geochemistry of Au-bearing pyrite from the Sepon Mineral District, Laos DPR, Southeast Asia: Implications for ore genesis
P Cromie, C Makoundi, K Zaw, DR Cooke, N White, C Ryan
Journal of Asian Earth Sciences | PERGAMON-ELSEVIER SCIENCE LTD | Published : 2018
Abstract
The Sepon gold-copper district occurs along the Truong Son Foldbelt in a 10 km × 40 km east-trending corridor in southern Laos. This study has investigated the nature of gold in pyrite and ore-forming fluid characteristics using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and Proton Induced X-ray Emission (PIXE) techniques. Gold is present as invisible gold (Au+1) and as nanoparticles of gold (Au0) in both sedimentary-rock hosted gold and skarn Cu-Au deposits. Gold is present in an early syngenetic pyrite generation (pyrite 2B) with concentrations to 0.5 ppm. Post-sedimentation processes included formation of quartz veins which host pyrite 3B with concentrations t..
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Funding Acknowledgements
The authors would like to thank the principal financial and logistical supporters for this research project, initially provided by Oxiana Limited and subsequent Sepon district project owners, namely: OZ Minerals Limited and then MMG Limited. The Centre for Ore Deposit Research and Exploration Science (CODES) at the University of Tasmania and CSIRO are thanked for providing research funding and technical support comprising the LA-ICP-MS and PIXE NMP techniques, respectively. The LXML (MMG Limited) exploration team at Sepon are also thanked for their technical support and helpful discussions during this research project. We also thank Dr. Martin Reich, Dr. Shaun Baker, Professor Pete Hollings, Dr. Mike Baker, Dr. Clive Burrett and Dr. David Houston for their substantial reviews and valuable suggestions that greatly improved the manuscript.