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Geodesy and Glaciology

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Paleo-dynamics and sediment transport of Ekströmisen, Dronning Maud Land

This interdisciplinary project integrates high-resolution seismic mapping with numerical models of ice dynamics, erosion and sediment transport to quantify the past and present interaction between glaciers and the solid Earth. We thus aim to test the hypothesis that subglacial sediment production, transport and deposition are key parameters for the past and present ice dynamics and stability of the Antarctic. For this purpose, a comprehensive source-to-sink concept is applied in one of the best limited glaciated catchment areas, the Ekströmisen in Dronning Maud Land, Antarctica. In the current debate on the stability of ice sheets and paleoclimatic conditions, we will help answer the following pressing scientific questions: How do Antarctic catchment areas behave over several glacial cycles? How did the grounded ice retreat in the Holocene? What are the decisive conditions for rapid ice transport in the catchment area? To what extent do erosion and deposition processes and the underlying strata influence ice dynamics and stability?

In order to answer these questions, we will link existing seismic data from subglacial layer packages with aero-geophysical information (ice thickness and internal stratigraphy from radar, geology from gravimetry and magnetism) and products of satellite remote sensing (surface height and ice flow velocity). A coupled higher-order ice flow-hydrology model is used to quantify the ice dynamics.  Initial conditions (distribution of liquid water and basal sediment and subglacial bedrock properties) are derived from radar and seismic data. Ice-dynamic simulations are coupled with a numerical model of glacial erosion, transport and deposition. These models will quantify the development of geometry, mass transport and basal conditions of the Ekströmisen catchment area over several glacial-interglacial cycles and will allow the investigation of possible feedbacks between basal sediments and ice dynamics. Observed sediment structures and core profiles are used to validate the simulated flow behaviour and erosion/sedimentation processes. Utilising the confined geometry of the Ekström basin, the project will overcome the limitations of the previous large scale source-to-sink sediment studies with multiple source regions and unconfined deposition zones. We will be able to quantify the ice-dynamic interaction with the continental bedrock and the coupling between the glacial and solid Earth system with unprecedented accuracy.

Project funded by the Priority Programme 1158 of the German Research Foundation (DFG): Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas

Project title: Constraining paleo-dynamics and sediment transport of Antarctic stream flow across grounding lines - from source to sink

Project managers: Todd Ehlers (U Tübingen), Olaf Eisen (AWI), Christoph Mayer (BAdW)