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

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This interdisciplinary project integrates high-resolution seismic imaging with numerical models of ice dynamics, erosion, and sediment transport to quantify past and present interactions between glaciers and the solid Earth. In doing this, we test the hypothesis that sub-ice sediment production, transport, and deposition are key controls on past and present day ice dynamics and stability in Antarctica. We will produce a physics based understanding of how ice flow interacts with the solid earth by comprehensivly employing a source-to-sink concept within one of the best geographically constrained glacial catchments, the Ekströmisen in Dronning Maud Land, Antarctica. Within the contemporary discussion of climate change, ice sheet stability, and paleoclimatic conditions, we will contribute to answering the following imminent scientific questions: How did Antarctic drainage basins behave during several glacial cycles? How did grounded ice retreat into the Holocence? What are the governing basal conditions for ice stream flow in drainage basins? To what degree do erosional and depositional processes and underlying strata influence ice dynamics and stability? To address these questions, we will integrate existing seismic data of subglacial strata (e.g. geomorphology and sediment basins) with aero-geophysical information (ice thickness and englacial stratigraphy from radar, geology from gravimetry and magnetics) and satellite remote sensing products (surface elevation and ice-flow velocity). A higher-order numerical ice-flow and subglacial hydrology model will be used to quantify Ekströmisens ice-flow dynamics. Initial conditions (distribution of liquid water, and properties of basal sediment and bedrock) will be derived from radar and seismic data. Ice flow simulations will be coupled with a numerical model for glacial erosion, transport and deposition. These models will quantify the development of Ekströmisens catchment areas geometry, mass transport and basal conditions over multiple glacial-interglacial cycles and enable investigation of possible feedbacks between basal sediment and ice dynamics. Observed sedimentary structure and core records are used to validate the simulated flow behaviour and erosion/sedimentation processes. Taking advantage of the Ekström basins confined geometry, the project will overcome the limitation of previous large-scale sediment source-to-sink studies with multiple source areas and unconfined deposition zones. We will quantify in unprecedented detail ice-dynamic interactions with the underlying strata and the coupling between glacial and solid Earth systems.