Element mobilities and the Australian regolith - a mineral exploration perspective

Abstract

Much of the Australian regolith ranges from Palaeogene to Late Cretaceous in age or even older, contrasting with the relatively young landscapes of the Northern Hemisphere. Hence, many imported geochemical exploration methods are unsuitable for Australian environments; this has led to successful homegrown innovation. Exploration geochemistry seeks to track geochemical anomalies arising from concealed ore deposits to their source. Much is known about element associations for different types of ore deposits and about observed patterns of dispersion. Element mobility in a range of Western Australian environments is discussed, drawing on field examples from the Mt Percy and Boddington gold mines and the Yandal greenstone belt, with reference to the effect of modern and past weathering regimes and the influence of groundwater on element mobility. Soil biota and vegetation affect Au mobility in the regolith, but specific processes, scale and environmental factors are unknown. Possible future synergies between biogeochemical or environmental research and regolith exploration geochemistry include determining the fundamental biogeochemical processes involved in the formation of geochemical anomalies as well as environmental concerns such as regolith aspects of land degradation. Exploration geochemists must study the work of biogeochemical and environmental researchers, and vice versa. There should also be collaborative research with regolith scientists and industry.