EGU21-6997
https://doi.org/10.5194/egusphere-egu21-6997
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Antarctic Sedimentary Basins: defining crucial constraints on ice-sheet and solid-earth dynamic interactions

Alan Aitken1, Lu Li1, Bernd Kulessa2,3, Thomas Jordan4, Joanne Whittaker2, Sridhar Anandakrishnan5, Jamin Greenbaum6, Dustin Schroeder7, Philippa Whitehouse8, Olaf Eisen9, and Martin Siegert10
Alan Aitken et al.
  • 1School of Earth and Environment, The University of Western Australia, Perth, Australia
  • 2The Institute of Marine and Antarctic Science, The University of Tasmania, Hobart, Tasmania, Australia
  • 3Glaciology Group, Faculty of Science & Engineering, Swansea University, Wales, UK
  • 4British Antarctic Survey, Cambridgeshire, UK
  • 5College of Earth and Mineral Sciences, Pennsylvania State University, Pennsylvania, USA
  • 6University of Texas Institute for Geophysics, University of Texas, Austin, Texas, USA
  • 7School of Earth, Energy and Environmental Sciences, Stanford University, California, USA
  • 8Department of Geography, University of Durham, Durham, UK
  • 9Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
  • 10Grantham Institute and Department of Earth Science and Engineering, Imperial College London, London, UK

Subglacial and ice-sheet marginal sedimentary basins have very different physical properties to crystalline bedrock and, therefore, form distinct conditions that influence the flow of ice above. Sedimentary rocks are particularly soft and erodible, and therefore capable of sustaining layers of subglacial till that may deform to facilitate fast ice flow downstream. Furthermore, sedimentary rocks are relatively permeable and thus allow for enhanced fluid flux, with associated impacts on ice-sheet dynamics, including feedbacks with subglacial hydrologic systems and transport of heat to the ice-sheet bed. Despite the importance for ice-sheet dynamics there is, at present, no comprehensive record of sedimentary basins in the Antarctic continent, limiting our capacity to investigate these influences. Here we develop the first version of an Antarctic-wide spatial database of sedimentary basins, their geometries and physical attributes. We emphasise the definition of in-situ and undeformed basins that retain their primary characteristics, including relative weakness and high permeability, and therefore are more likely to influence ice sheet dynamics. We define the likely extents and nature of sedimentary basins, considering a range of geological and geophysical data, including: outcrop observations, gravity and magnetic data, radio-echo sounding data and passive and active-source seismic data. Our interpretation also involves derivative products from these data, including analyses guided by machine learning. The database includes for each basin its defining characteristics in the source datasets, and interpreted information on likely basin age, sedimentary thickness, surface morphology and tectonic type. The database is constructed in ESRI geodatabase format and is suitable for incorporation in multifaceted data-interpretation and modelling procedures. It can be readily updated given new information. We define extensive basins in both East and West Antarctica, including major regions in the Ross and Weddell Sea embayments and the Amundsen Sea region of West Antarctica, and the Wilkes, Aurora and Recovery subglacial basins of East Antarctica. The compilation includes smaller basins within crystalline-bedrock dominated areas such as the Transantarctic Mountains, the Antarctic Peninsula and Dronning Maud Land. The distribution of sedimentary basins reveals the combined influence of the tectonic and glacial history of Antarctica on the current and future configuration of the Antarctic Ice Sheet and highlights areas in which the presence of dynamically-evolving subglacial till layers and the exchange of groundwater and heat with the ice sheet bed  are more likely, contributing to dynamic behaviour of the Antarctic Ice Sheet.  

How to cite: Aitken, A., Li, L., Kulessa, B., Jordan, T., Whittaker, J., Anandakrishnan, S., Greenbaum, J., Schroeder, D., Whitehouse, P., Eisen, O., and Siegert, M.: Antarctic Sedimentary Basins: defining crucial constraints on ice-sheet and solid-earth dynamic interactions, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6997, https://doi.org/10.5194/egusphere-egu21-6997, 2021.

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