Carbonate cycles in Aptian- Albian ' black- shales' of the Falkland Plateau ( DSDP Leg 71 Site 511, Cretaceous).

Cretaceous cores from DSDP Leg 71, Site 511, drilled on the eastern Falkland Plateau were examined via carbonate, organic carbon, stable isotope, nannofloral, and ultrastructural analysis in an attempt to determine the mode of origin of thin but discrete pelagic limestone beds intercalated among the black mudstones near the top of the extensive Mesozoic 'black-shale' sequence. The 'black shales' are of interest because of their paleoenvironmental significance and their potential as a source rock for petroleum in and around the South Atlantic Basin. Episodes of upwelling and overturn of the water column, rather than influxes of well-oxygenated waters into an otherwise anoxic environment are suggested by both the nannofloral and isotopic analyses as a possible mode of origin of the thin but discrete pelagic limestone beds intercalated among the Falkland Plateau Aptian-Albian black mudstones.-from Current Antarctic Literature