Geology, Geochemistry and Formation of Supergene Mineral Deposits in Deeply Weathered Terrain

Rob Bowell is Corporate Consultant with SRK Consulting and an adjunct professor in the Department of Geological Sciences and Geological Engineering at Queen’s University, Kingston, Ontario, Canada and a research fellow of the Queen’s Facility for Isotope Research. He has 35 years of experience in the global mining industry. His background is in exploration and mining in tropical and deeply weathered terrain’s including extensive work in Equatorial and Southern Africa, South America and Southeast Asia. He holds degrees in chemistry, geology, chemical engineering and a PhD in geochemistry on the occurrence of oxide gold deposits in Ashanti, Ghana. He has worked for TCL, Ashanti and Minorco prior to joining SRK. For the last 29 years he has worked in mining consulting in the fields of due diligence, financial and technical audits, process chemistry, environmental geochemistry, environmental engineering and mineralogy. Specializes in the application of chemistry and mineralogy to solve engineering problems. Has been involved in the discovery of copper projects that have been developed into mines in DRC, Namibia and Zambia and discovered Gold and Diamond deposits in the Dodoma region of Tanzania and in northern Mozambique. He is currently involved in the development of the Kuene Copper districty in Northern Namibia. He has authored/coauthored over 250 papers, edited monographs and reports including one on Arsenic as Reviews in Mineralogy & Geochemistry, volume 79 and edited as well contributed to volumes on applied chemistry/geochemistry for Nova Publishing series on chemical elements. He is deputy chief editor for Geochemistry, Exploration, Environment and Analysis and past president of the Association of Applied Geochemists.Charles R. M. Butt is an exploration geochemist and regolith geologist with over 50 years research experience in deeply weathered terrain. He has mainly concentrated on the development of exploration procedures for gold, nickel, platinum-group elements, uranium and base metals, and in the geology of secondary mineral deposits, particularly surficial uranium, nickel-cobalt laterite and supergene gold. Both themes have required an understanding of the processes of chemical weathering during the formation of intensely weathered and lateritic regolith, and the subsequent influences of climatic, tectonic and other environmental changes on their evolution, a focus of this volume.Charles was formerly Deputy Director, CRC for Landscape Evolution and Mineral Exploration, and Chief Scientist, CSIRO Division of Exploration and Mining, based in Perth, Western Australia. He is now an Honorary Research Fellow with CSIRO Mineral Resources. He has led many industry-funded research projects in Australia, and delivered courses and field workshops to industry, university extension and government in Australia, Canada and several countries in South America and Africa. He was awarded the Gold Medal of the Association of Exploration (now Applied) Geochemists, Gibb Maitland Medal (Geological Society of Australia) and A.B Edwards Medals (Australian Journal of Earth Sciences). He was elected Fellow of the Australian Academy of Technological Sciences in 2004.Charles Butt has authored/co-authored over 300 papers, reports and other articles, including reviews of oreforming processes related to lateritic weathering. Edited books include Regolith exploration geochemistry in tropical and subtropical terrains (CRM Butt and H Zeegers, Handbook of Exploration Geochemistry 3.). He was Associate Editor of the Journal of Geochemical Exploration (1976-1999) and Geochemistry: Exploration, Environment, Analysis (2000-2010), and Guest Editor for special issues of thesejournals, the Australian Journal of Earth Sciences and Elements.

• 1 Introduction.- 2 Geochemistry of supergene processes.- 3 Geology of supergene deposits.- 4  Formation of supergene deposits.- 5 ulfide oxidation and gossan formation.- 6 Tropical weathering model  (lateritic, ferrasol and podsol sub-types).- 7 Glaciation weathering model and profile denudation.- 8 Caliche weathering model.- 9 Groundwater mobilization and enrichment.- 10 Surface water physical erosion model.- 11 Immature digenesis model.