Two samples of Miocene sediments from Site 525 and four samples of sediments ranging in age from Pleistocene to Miocene from Site 528 have been analyzed for concentrations of organic and carbonate carbon, carbon/nitrogen ratios of organic matter, and extractable hydrocarbons and fatty acids. Organic carbon concentrations average 0.32% and show a diagenetic decrease with greater sediment age. Distributions of n-alkanes and n-alkanoic acids give evidence of considerable microbial reworking and of eolian contributions of terrigenous components. Organic contents of these sediments reflect a history of low marine productivity and poor preservation of organic matter in the eastern South Atlantic since middle Miocene times.

Supplement to: Meyers, Philip A; Keswani, Sushiel R (1984): Organic geochemistry of Neogene sediments from the Walvis Ridge, Deep Sea Drilling Project Leg 74. In: Moore, TC Jr; Rabinowitz, PD; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 74, 731-736