Constraining paleo-dynamics and sediment transport of Antarctic stream flow across grounding lines - from source to sink
Final Report Abstract
We investigated the past and present behaviour of the Ekströmisen ice shelf by combining observations of seafloor topography and numerical models. A special focus was put on the interaction of the ice shelf’s ice dynamics with the underlying strata and the neighbouring ice rises, where ice is grounded. Major results include the detection of a subglacial trough, which confirms the activity of a paleo ice stream. From disturbances in the seafloor topography we conclude that the grounded part of the ice stream extended almost up to the continental shelf break. Modelling results indicate that the response of the grounded parts next to the floating ice shelf react differently to changes in the overall snow accumulation than to disintegration of the ice stream. Our approach presents a new tool to use ice rises as paleo archive for the ice-sheet history, which can now be employed at other ice rises surrounding Antarctica as well. The properties of the seafloor, e.g. hard bedrock or soft sediments, have an considerable effect on the extent of the grounded part of the ice stream as well as the time needed for advance or retreat. These numerical modelling results were made possible by considerably improving the performance of the employed model. These results will help to better constrain the uncertainties coming along with modelling past ice stream dynamics and their contributions to sea level change in those cases where the properties of the seafloor are unknown. Scientifically, it was a surprise how bad the existing compilations of Ekströmisen’s ice shelf cavity bathymetry has been. This means that basically all available ice shelf bathymetries are unreliable unless at least some direct observations do exist. Over the course of the project, some short reports were published on AWI Glaciology’s “Eisblog”, where ongoing work is presented in a way to enable the general public to follow activities: https://blogs.helmholtz.de/eisblog/category/schelfeis/
Publications
- (2019) Coring of Antarctic Subglacial Sediments, Journal of Marine Science and Engineering, 7(6), p. 194
Gong, D. , Fan, X. , Li, Y. , Li, B. , Zhang, N. , Gromig, R. , Smith, E., Dummann, W. , Berger, S., Eisen, O., Tell, J. , Biskaborn, B. K., Koglin, N. , Wilhelms, F., Broy, B. , Liu, Y. , Yang, Y. , Li, X. , Liu, A. and Talalay, P.
(See online at https://doi.org/10.3390/jmse7060194) - Detailed seismic bathymetry beneath Ekstroem Ice Shelf, Antarctica: Implications for glacial history and ice-ocean interaction, Geophysical Research Letters, 47, e2019G
Smith, E., Hattermann, T., Kuhn, G., Gaedicke, C., Berger, S., Drews, R. , Ehlers, T. A. , Franke, D. , Gromig, R. , Hofstede, C. , Lambrecht, A. , Laeufer, A. , Mayer, C. , Tiedemann, R., Wilhelms, F., O.
(See online at https://doi.org/10.1029/2019GL086187) - Kinematic response of ice-rise divides to changes in oceanic and atmospheric forcing, The Cryosphere, 13, 2673–2691, 2019
C. Schannwell, R. Drews, T. A. Ehlers, O. Eisen, C. Mayer, and F. Gillet Chaulet
(See online at https://doi.org/10.5194/tc-13-2673-2019) - (2020) Bathymetry beneath ice shelves of western Dronning Maud Land, East Antarctica, and implications on ice shelf stability, Geophysical Research Letters, 47(12), e2019GL086724
Eisermann, H., Eagles, G., Ruppel, A., Smith, E., W.
(See online at https://doi.org/10.1029/2019GL086724) - (2020) Deep glacial troughs and stabilizing ridges unveiled beneath the margins of the Antarctic ice sheet, Nature Geoscience, 13, pp. 132-137
Morlighem, M. , Rignot, E. , Binder, T. , Blankenship, D. , Drews, R. , Eagles, G., Eisen, O., Ferraccioli, F. , Forsberg, R. , Fretwell, P. , Goel, V. , Greenbaum, J. S. , Gudmundsson, H. , Guo, J. , Helm, V., Hofstede, C. , Howat, I. , Humbert, A. , Jokat, W., Karlsson, N. B. , Lee, W. S. , Matsuoka, K. , Millan, R. , Mouginot, J. , Paden, J. , Pattyn, F. , Roberts, J. , Rosier, S. , Ruppel, A. , Seroussi, H. , Smith, E. C., Steinhage, D., Sun, B. , Broeke, M. R. v. d. , Ommen, T. D. v. , Wessem, M. v. and Young, D. A.
(See online at https://doi.org/10.1038/s41561-019-0510-8) - Quantifying the effect of ocean bed properties on ice sheet geometry over 40 000 years with a full-Stokes model, The Cryosphere, 14(11), pp. 3917- 3934
Schannwell, C., Drews, R. , Ehlers, T. A. , Eisen, O., Mayer, C. , Malinen, M. , Smith, E. C., H.
(See online at https://doi.org/10.5194/tc-14-3917-2020)
