POMklim Tuesday March 9

Abstract

Large-scale and rapid variability in both space and time has been noted in Antarctic and Greenland ice streams. It is however, difficult to assess whether these are natural fluctuations in a stable system, or if they indicate instability and an acceleration of mass loss. The palaeo-record has great potential to provide a longer term perspective and improve understanding of the natural variability in contemporary ice masses. I will use two examples from our work in the Barents Sea to demonstrate this potential.

The first study used megascale geomorphic mapping of the southern Barents Sea seafloor, northern Fennoscandia and the Kola Peninsula as the basis for a new reconstruction of the deglaciation of the Barents Sea Ice Sheet. This reconstruction focused on the behaviour and influence on ice streaming of the retreat of this marine-based ice sheet. The second example used 3D seismic data to investigate the internal structure of subglacial tills in Bjørnøyrenna. This revealed successive series of megablocks and megascale glacial lineations, indicating repeated switching of the ice stream between periods of fast flow to periods of quiescence. Such behaviour was noted over multiple glaciations, suggesting that this may be a common behaviour of marine ice streams.

I will finish by introducing a new project, which will use three different numerical models to improve knowledge of the Late Cenozoic geological evolution of the Barents Sea area: (1) a 3D ice sheet model will provide simulations of the Barents Sea- Fennoscandia Ice Sheet during the last glacial cycle, (2) a 2D flowline model of ice stream grounding line retreat will test ice stream sensitivities to internal and external forcing factors, and (3) a 2D flowline model of basal sediment transport will investigate the erosion, transport and deposition of ice stream subglacial sediments.

POMklim is the lunch-time (mostly) polar climate research seminar series at POMI. The aim of POMklim is to promote cross-institutional and multi-disciplinary discussions and cooperation on all aspects of polar climate. Absolutely all are welcome.

POMklim organizer:

Dr. Jack Kohler

Norwegian Polar Institute

Polar Environmental Center