Weathering geochemistry and Sr-Nd fingerprints of equatorial upper Nile and Congo muds

Abstract

This study investigates processes of sediment generation in equatorial central Africa. An original, complete and integrated mineralogical-geochemical database on silt-sized sediments derived from different parent rocks (basalt, granite, gneiss, metapsammite, sandstone) along the East African Rift from 5°S in Tanzania to 5°N in Sudan is presented and used to assess the incidence of diverse factors controlling sediment composition (source-rock lithology, geomorphology, hydraulic sorting, grain size, recycling), with particular emphasis on chemical weathering. Key Points Integrated mineralogical-geochemical study of weathering in equatorial Africa Composition of river muds reflects weathering intensity and its controls Contrasting behavior of weathering indices quantifies recycling ©2013. American Geophysical Union. All Rights Reserved.