Biostratigraphy and average linear sedimentation rate and accumulation rate of ODP Site 159-959 (Table 1)

• Main Author: Wagner, Thomas
• Format: Dataset
• Language: English
• Published: PANGAEA 2002
• Subjects: 159-959; Accumulation rate; mass; AGE; Biozone; COMPCORE; Composite Core; DEPTH; sediment/rock; DSDP/ODP/IODP sample designation; Epoch; Gulf of Guinea; Joides Resolution; Leg159; Lithologic unit/sequence; Lithology/composition/facies; Ocean Drilling Program; ODP; Reference/source; Sample code/label; Sedimentation rate; Southern Ocean
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.706283; https://doi.org/10.1594/PANGAEA.706283

Reconstructing the long-term evolution of organic sedimentation in the eastern Equatorial Atlantic (ODP Leg 159) provides information about the history of the climate/ocean system, sediment accumulation, and deposition of hydrocarbon-prone rocks. The recovery of a continuous, 1200 m long sequence at ODP Site 959 covering sediments from Albian (?) to the present day (about 120 Ma) makes this position a key location to study these aspects in a tropical oceanic setting. New high resolution carbon and pyrolysis records identify three main periods of enhanced organic carbon accumulation in the eastern tropical Atlantic, i.e. the late Cretaceous, the Eocene-Oligocene, and the Pliocene-Pleistocene. Formation of Upper Cretaceous black shales off West Africa was closely related to the tectonosedimentary evolution of the semi-isolated Deep Ivorian Basin north of the Côte d'Ivoire-Ghana Transform Margin. Their deposition was confined to certain intervals of the last two Cretaceous anoxic events, the early Turonian OAE2 and the Coniacian-Santonian OAE3. Organic geochemical characteristics of laminated Coniacian-Santonian shales reveal peak organic carbon concentrations of up to 17% and kerogen type I/II organic matter, which qualify them as excellent hydrocarbon source rocks, similar to those reported from other marginal and deep sea basins. A middle to late Eocene high productivity period occurred off equatorial West Africa. Porcellanites deposited during that interval show enhanced total organic carbon (TOC) accumulation and a good hydrocarbon potential associated with oil-prone kerogen. Deposition of these TOC-rich beds was likely related to a reversal in the deep-water circulation in the adjacent Sierra Leone Basin. Accordingly, outflow of old deep waters of Southern Ocean origin from the Sierra Leone Basin into the northern Gulf of Guinea favored upwelling of nutrient-enriched waters and simultaneously enhanced the preservation potential of sedimentary organic matter along the West African continental margin. A ...