Gold: A tracer of the dynamics of tropical laterites

Lareites have developed essentially from long-term exposure of cratonal rocks to the atmosphere and hydrosphere. The properties of gold (density and relative insolubility) make residual gold parrticles tracers of surficial processes causing mineralized laterites. Gold particles are useful in distinguishing between in situ chemical weathering and physical transport on African lateritic systems developed on slowly eroding stble landforms. In an equatorial rainforest setting, chemical dissolution and translocation of fine particles are the dominant processes. Episodic alluvial and/or colluvial transport appears to contribute to laterite formation in the subsahelian steppe. The use of gold particles, coupled with the examination of in situ 10Be from auriferous quartz, indicates the applicability of such methods for examination of laritic weathering dynamics of the tropical "transcontinental" lithosphere.