Sedimentology on Quaternary depoits from the Weddell Sea continental slope

• Main Author: Bonn, Wolfgang J
• Format: Other/Unknown Material
• Language: English
• Published: PANGAEA 2009
• Subjects: ANT-IX/3; ANT-VI/3; ANT-VIII/6; Atka Bay; AWI_Paleo; Fram Strait; Gravity corer (Kiel type); Lazarev Sea; Paleoenvironmental Reconstructions from Marine Sediments @ AWI; Polarstern; PS12; PS12/248; PS12/536; PS1575-1; PS16; PS16/534; PS16/541; PS1648-1; PS18; PS18/184; PS18/185; PS18/186; PS18/187; PS18/191; PS18/192; PS18/193; PS18/194; PS18/196; PS18/198; PS18/203; PS18/204; PS1821-6; PS1824-1; PS2037-3; PS2038-2; PS2039-1; PS2040-2; PS2044-1; PS2045-3; PS2046-1; PS2047-3; PS2049-4; PS2050-1; PS2055-2; PS2056-1; Silicon Cycling in the World Ocean; SINOPS; SL; South Orkney; Antarc*; Antarctic; Berichte zur Polarforschung; Ice Sheet; Polar Research; Polarforschung; Reports on polar research; Weddell Sea
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.729792; https://doi.org/10.1594/PANGAEA.729792

Sedimentological, geochemical (in particular biogenic content) and physical properties from the Weddell, Lazarev and Cosmonaut seas along the Antarctic continental margin were analysed in order to reconstruct the late Quaternary productivity and sedimentary processes of this region. Seven undisturbed sediment cores were chosen. The sediments represent a depositional period from 400,000 years to the recent time. The late Quaternary climatic changes influence changes in the paleoenvironmental and the geological conditions, directly forced by the behaviour of the Antarctic ice sheet. All investigated cores are positioned within the oscillating ice sheet area and reflect the influence of the ice sheet in response to the climatic cycles. The organic carbon, carbonate, biogenic opal, and barium contents were measured, andlor calculated, together with the determination by XRD of the terrigenous components such as quartz and plagioclase (expressed as relative to corundum standard). The contents of organic carbon and carbonate in general are very low. The results provide an indication that organic carbon content is a preservation signal and not a productivity signal. Carbonate is not correlated with biogenic opal and biogenic barium. Profiles of biogenic opal and barium were measured within the sediment cores providing a qualitative and quantitative tool to estimate changes in paleoproductivity over the investigated time. Generally, good correlations between the barium and opal records of the sediment cores indicate that dissolution of opal in the water column and the sediment does not obscure the surface productivity signal. Therefore, opal can be used in combination with other proxies for paleoproductivity discussions in this area. Maximum paleoproductivity rates (PPmax) during peak warm stages reach values between 82-345 gC/m2/a and maximum export productivity rates (Pnew, max) between 14-177 gC/m2/a, that are representative of high-productivity areas. They are drastically reduced during glacial times (PPmax = 14-107 ...