Stable isotope (carbonates), organic carbon, calcium carbonate and occurrence of coccoliths at DSDP Hole 71-511, supplement to: Parker, Mary E; Arthur, Michael A; Wise, Sherwood W; Wenkam, Chiye R (1983): Carbonate and organic carbon cycles in Aptian–Albian black shales at Deep Sea Drilling Project Site 511, Falkland Plateau. In: Ludwig, WJ; Krasheninnikov, VA; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 71, 1051-1070

• Main Authors: Parker, Mary E, Arthur, Michael A, Wise, Sherwood W, Wenkam, Chiye R
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 1983
• Subjects: Drilling/drill rig; Leg71; Glomar Challenger; Deep Sea Drilling Project DSDP; Falkland Plateau; North Atlantic
• Online Access: https://dx.doi.org/10.1594/pangaea.815293; https://doi.pangaea.de/10.1594/PANGAEA.815293

Thin but discrete pelagic limestone beds intercalated among the black mudstones near the top of the extensive Mesozoic black shale sequence of the Falkland Plateau are reminiscent of similar occurrences in the central and North Atlantic and may be cyclic in nature. They have been studied via carbonate, organic carbon, stable isotope, nannofloral, and ultrastructural analysis in an attempt to determine their mode of origin. Nannofossil diversity and preservation suggest that selective dissolution or diagenesis did not produce the interbedded coccolith-rich and coccolith-poor layers, nor did blooms of opportunistic species play a role. Stable isotope measurements of carbonate do not adequately constrain the origin of the cyclicity; however, the d13C data suggest that the more nannofossil-rich intervals may be due to higher nutrient supply and overturn of deeper waters at the site rather than influxes of well-oxygenated waters into an otherwise anoxic environment. Such an explanation is in accord with the nannofloral evidence