Genesis of esker corridors as erosional features beneath ice sheets
Abstract
When the large Pleistocene ice sheets retreated during the last deglaciation, eskers were deposited along subglacial channels. The eskers are principally composed of loose sediment transported in subglacial channels fed by meltwater. The chief source of meltwater was surface melt from the ice sheet with some basal melt. However, sediment transported to the esker is derived from the basal system. Evidence from esker systems show that corridors lateral to the eskers are stripped of fine sediments with topographic depressions. These esker corridors can be approximately 10 km wide and are indicative of the surface melt of the ice sheet. Thus, the eskers and their corridors give insight into how the ice sheet collapsed. Here, we use a numerical model of water and sediment transport to understand how esker corridors form. Our results show how upstream melt rate leads to development of the drainage system lateral to the channel. A low pressure (high effective pressure) boundary layer forms near the channel, conducting water and eroding sediments. We discuss how this boundary layer varies to produce variable corridor widths and ultimately yield insight into the surface melt of the ice sheet during its demise.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C21E1496C
- Keywords:
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- 0726 Ice sheets;
- CRYOSPHERE;
- 1616 Climate variability;
- GLOBAL CHANGE;
- 1621 Cryospheric change;
- GLOBAL CHANGE;
- 1641 Sea level change;
- GLOBAL CHANGE