In many deep-sea sediments Mn-rich layers are observed at various levels. In order to investigate their formation and preservation as well as their use to reconstruct past changes in the depositional environment downcore profiles of manganese and manganese carbonate from different early diagenetic environments in the Southeast Atlantic Ocean were examined by geochemical analysis, X-ray diffraction and SEM-analysis. The results were compared to pore water data and productivity regimes. In sediments underlying areas of high to moderate surface water fertility Mn is reduced and recycled to overlying waters or precipitated at the oxic/suboxic boundary within the sediment, forming subsurface Mn-spikes. Manganese carbonate is a characteristic feature of these early diagenetic Mn-enrichments. In the cores from the Equatorial Divergence where glacial-interglacial productivity changes have been recorded by geochemical and isotopical evidence manganese carbonate peaks occur at deglaciation phases (decreased supply of organic matter) though the total manganese contents are nearly constant indicating that manganese carbonate survives burying to anoxic sediments better than Mn(IV)-phases. In sediments of the central Walvis Ridge underlying nutrient-poor surface waters peaks of Mn(IV) and manganese carbonate occur in glacial sections thus giving evidence of higher reduction rates through increased supply of the reducing organic matter. The higher flux of organic matter is attributed to a higher surface water productivity during glacials on the central Walvis Ridge. Since the evaluation of paleoproductivity proxies in that area is ambigous, the interpretation of manganese and manganese carbonate profiles is an important qualitative tool supporting glacial-interglacial changes in paleoproductivity. © 1994.