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[1] 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. [2] Kaolinite abundance, CIA, and a Al values consistently indicate less intense weathering along the steep inner flank and drier axis of the rift hosting Lakes Kivu and Tanganyika than in hot-humid forested highlands east of the Nile-Congo divide, where slopes are gentler and time for weathering longer. The observed order of bulk-sediment mobility (Na ≥ Ca > Sr > Mg > K > Ba ≥ Rb > Cs) roughly corresponds to the degree into which these elements are partitioned in unstable plagioclase versus K-feldspar and phyllosilicates. Weathering-limited erosion characterizes the Rwenzori massif and the Lake Albert

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