Pre-glacial to glacial seismostratigraphy of the Amundsen Sea Embayment shelf, West Antarctica

• Main Authors: Gohl, Karsten, Hochmuth, Katharina, Uenzelmann-Neben, Gabriele
• Format: Conference Object
• Language: unknown
• Published: 2012
• Subjects: Amundsen Sea; Antarc*; Antarctic; Antarctica; Ice Sheet; Pine Island; Pine Island Bay; West Antarctica
• Online Access: https://epic.awi.de/id/eprint/25872/; https://hdl.handle.net/10013/epic.38791

Recent retreat rates of glacier systems in the Amundsen Sea Embayment and, in particular, Pine Island Bay have placed this region into focus for predicting the dynamics of the West Antarctic Ice Sheet and sea-level rise. The architecture of continental shelf and slope sediments represents stages of the glacial history from early glaciation to the last glacial period. A new large dataset of seismic profiles collected on the shelf, slope and rise provides new insight into the preglacial, glacial and glacio-marine processes. The data reveal an heterogeneous outer shelf with areas of pronounced progradation while other areas lack this depositional configuration almost entirely. In some parts, sediments deposited across the shelf break enlarged the outer shelf by up to 60 km oceanward. While most of the glacial troughs – palaeo-ice stream pathways – have remained stationary, at least one major trough has shifted position, width and direction since early glaciation. These deep troughs are significant for incursions of Circum-Polar Deep Water onto the shelf, which is implicated as the driver of recent changes. Observed grounding zone wedges indicate stages when grounding zones where stationary for some time or re-advanced. These observations show that ice sheet dynamics on the shelf has constantly altered seafloor morphology and deposition throughout glacial cycles. Although chronological control of the strata is still missing, this first seismic horizon-stratigraphic model for the Amundsen Sea Embayment shelf serves as a basis for understanding processes of glacial advance and retreat. It also supports the active drill proposal IODP 784 for drilling into shelf sediments with the objective to reconstruct past dynamics of the West Antarctic Ice Sheet.