The research infrastructure that is the subject of this proposal are the lake-sediment cores from Lake Challa to be recovered by ICDP project DeepCHALLA, and which represent a globally unique resource for reconstructing the climate and environmental history of East Africa over the past ~250,000 years. Our specific aim is to retrieve continuous sediment sequences (as cores drilled in consecutive 3-m sections) from 3 sites within Lake Challa, each in triplicate to ensure that the overlapping sections together constitute an uninterrupted sample of the in situ sediment profile. The 3 sites are arranged in a nearshore-offshore transect and drilled to respectively ~25 m, ~100 m and ~210 m depth, thus allowing to determine the influence of near-shore sedimentation dynamics on the signatures of climate and ecosystem proxies preserved in the longest sequence from the lake center. Together these 9 drill cores will amount to ~1000 m of sediment contained in transparent butyrate core liners.