Topographic control on Precambrian weathering in the Elliot Lake uranium district, Canada

The voluminous uraniferous conglomerate beds at Elliot Lake, Canada lie directly above or within several metres of a palaeosol that developed on Archaean granite and greenstone (metabasalt). This Lower Proterozoic paleosol provides evidence for the environment in which the uraniferous conglomerate accumulated. Previous investigators have interpreted a few analyses of the palaeosol to indicate palaeoweathering under an atmosphere devoid of free oxygen. However, we have independently analysed in detail three oxidized palaeosols that formed contemporaneously with reduced palaeosols. The degree of oxidation correlates well with palaeoelevation.