A High-Resolution 17 kyr Paleoproductivity History off NW Africa Inferred From Benthic Foraminifera

The Cape Blanc region off Mauritania, NW Africa, forms an import site for investigating paleoproductivity responses to past oceanographic changes. Today it sits at the boundary between cool temperate and subpolar water masses in the north and warm tropical water masses to the south and west. In addition, the region is characterised by extensive upwelling and a high supply of terrestrial input, leading to high primary productivity. Slight changes in the location of the boundary between the water masses can potentially have a large impact on the productivity of the region. In this study we investigate high-frequency variability in paleoproductivity in the area over the last 17 000 years and relate this to changes in upwelling and terrestrial input. To this end, core GeoB7926-2 was recovered from 2500 m water depth at 20°13N, 18°27W. This well-dated core has sedimentation rates of 70 to 160 cm per kyr over the last 17 000 years, making it highly suitable for detecting subtle productivity and oceanographic changes. A centennial to millennial record of benthic foraminifera variability will be presented, and compared to other parameters measured in the core including stable oxygen and carbon isotopes from both benthic and planktic foraminifera, bulk biogenic sediment variables, such as organic carbon, calcium carbonate and biogenic silica.