QUATERNARY TECTONICS AND CLIMATIC RECORD IN TROPICAL WEATHERING PROFILES

Laterite, an iron-rich, residual weathering mantle of the tropical reg ion, is preserved over a long period and shows at many places records of polyphase development. These phases embrace mineralogical proxies o f arid and humid cycles, which correspond to glacial and interglacial epochs of the Pleistocene. Lateral juxtaposition of different levels o f the laterite catena (duricrust, structured saprolite, flat-layered s aprolite, etc.) can be used as a tool for locating zones of vertical d isplacement in older terrains. In the absence of dependable techniques of absolute age dating, old laterites in the mess tops with localized concentrations of Fe, Al, Ni, precious and rare metals, as well as th e vast laterite-covered areas concealing zones of endogenetic mineral concentration, have so far attracted more prospectors than geoscientis ts, essentially because the laterite provides but an imperfect record of dynamic pedogenesis in the tropical belt over more than a million y ears.