Subglacial landscapes in Greenland: Obscure(d) insights into past climates, environments, and ice sheets

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• Guy Paxman, Lamont-Doherty Earth Observatory
• Tuesday 15 February 2022, 14:00-15:00
• Online (contact organiser for Zoom link).

If you have a question about this talk, please contact Dr Alex Bradley.

The landscape hidden beneath the Greenland Ice Sheet remains one of the most sparsely mapped regions on Earth, but offers a unique record of environmental conditions prior to and during widespread glaciation, and of the ice sheet’s response to changing climates. In particular, the bed topography bears the signatures of past processes of landscape evolution, which can in turn be used to build an understanding of the geological, glaciological, and climatological history of Greenland. In this talk I will present radar, gravity, and magnetic data from northern Greenland, acquired during a decade of Operation IceBridge geophysical surveys over the Greenland Ice Sheet. Radar data are used to map an enclosed subglacial basin and a network of subglacial valleys, and geomorphological analysis is used to infer that these features represent a palaeo-lake basin and palaeo-fluvial channels that formed prior to widespread glaciation. Modelling of gravity and magnetic anomalies indicates that the morphology and spatial organisation of these topographic features is influenced by the regional-scale geological structure, implying a long-lived and well-established hydrological system. I will also outline geophysical evidence that indicates that the palaeo-lake basin contains a sedimentary infill approximately one kilometre thick. Based on these findings and recent analysis of subglacial material from the nearby Camp Century ice core, this newly identified palaeo-lake basin may contain palaeoclimatically valuable sedimentary records of ice sheet extent and environmental conditions in northwest Greenland during (e.g.) interglacial periods of the Pliocene / Pleistocene. This region may therefore represent a promising target for future acquisition of ground-based active source seismic data and potential recovery of subglacial material by sub-ice drilling programs.

This talk is part of the British Antarctic Survey - Ice Dynamics and Paleoclimate Seminar Series series.

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• British Antarctic Survey - Ice Dynamics and Paleoclimate Seminar Series
• Online (contact organiser for Zoom link)

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