Seismostratigraphic Analysis and Glacial History of the Weddell Sea Region, Antarctica

Abstract

The Weddell Sea basin is of particular significance for understanding climate processes, including the generation of ocean water masses and their influence on ocean circulation as well as the dynamics of the Antarctic ice sheets. The sedimentary record, preserved below the basin floor, serves as an archive of the pre-glacial to glacial development of these processes, which were accompanied by tectonic processes in its early glacial phase. Three multichannel seismic reflection transects, in total nearly 5,000 km long, are used to interpret horizons and define a seismostratigraphic model for the basin. We expand this initial stratigraphy model to the greater Weddell Sea region through a network of more than 50 additional seismic lines. Information from few boreholes are used to constrain sediment ages in this stratigraphy, supported by magnetic anomalies indicating decreasing oceanic basement ages from southeast to northwest. Using these constraints, we calculate grids to depict the depths, thicknesses and sedimentation rates of pre-glacial (145–34 Ma), transitional (34–15 Ma) and full-glacial (15 Ma to present) units. Sedimentation thicknesses and sedimentation rates were calculated at the 12 selected points in the entire basin to give a brief overview of the deposition history, which will contribute to the understanding of the Antarctic ice sheet development and dynamics from the greenhouse to icehouse world in the Cenozoic.