Albian paleoceanography and paleotemperatures of the tropical western Atlantic (ODP Leg 207, Demerara Rise) - the onset of the mid-Cretaceous super-greenhouse climate.

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This project aims at deciphering the paleoceanographic, paleoclimatic and paleoecologic conditions of the mid to late Albian at one of the warmest locations of the Cretaceous ocean, the tropical proto-North Atlantic. Another important aspect is the reconstruction of the oceanographic conditions, which led to the long lasting-deposition of organic-rich sediments at Demerara Rise and if warm, saline bottom waters occurred as early as the Albian. This will be achieved by studying material from the Demerara Rise (ODP Leg 207). Demerara Rise occupies a central position for understanding mid-Cretaceous water temperatures and the mechanisms of Cretaceous black shale deposition. Stable isotopes of organic matter and planktic and benthic foraminifers (δ18O, δ13C) as well as benthic foraminiferal assemblages from Site 1258 will be used to achieve the following main goals: (1) Establishing a mid to Late Albian chemostratigraphy, (2) expanding the existing SST and deeper water paleotemperature history in the core of the tropics into the Albian, (3) deciphering the trigger mechanisms of OAE 1d formation in the tropical Atlantic, (4) clarifying if warm, saline deep waters existed in the Albian and, if yes, their role for marine ecosystems and source-rock formation, and (5) investigating the ecology of foraminifera in organic-rich environments.