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Nannofacies analyses of 65 samples of Upper Aptian and Albian black shales from the Falkland Plateau, the Cape Basin, and the continental margin off Angola (South Atlantic, DSDP Leg 36, sites 327 to 330; DSDP Leg 40, sites 361 to 364) provide data on depositional environment. The presence of nannoplankton shows undeniable marine conditions, productivity of surface waters, and oceanic connections. The mode of fossilization (coccolith aggregates interpreted as coccospheres dislocated on the spot) indicates stagnant and confined depositional conditions, which are confirmed by the presence of pyrite framboids. Coccoliths that are present only as casts show that dissolution processes took place in the sediment and not in the water column.
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