Subglacial Sediment and Ice Sheet Motion

Dr. Anders Carlson

Collaborators:

John Jenson (U. of Guam), Chandra Desai (U. of Arizona), Dinshaw Contractor (U. of Arizona)

This collaborative research project is using field observations, geotechnical experiments and finite element and difference models to investigate the behavior of till under ice sheets and the development of subglacial drainage systems.

Schematic of how warm-based glaciers and ice sheets move through internal deformation, sliding at the ice-till interface and subglacial sediment deformation.

We are focusing on two regionally significant tills, the Tiskilwa Till of Illinois deposited by the Lake Michigan Lobe and the Sky Pilot Till of the Hudson Bay Lowlands (see picture below).

Picture of a bluff exposure along the Nelson River, MB of the Sky Pilot Till.

This project is in its second iteration now, with funding coming from NSF. In particular, we are interested in the role of till in restraining fast-ice motion (see figure below) and the how the basal drainage system may regulate this motion. We are continuing geotechnical and field studies focusing on the interface between ice and till, and are now developing our finite element till model to include an ice sheet, sediment rheology, ice-till interface behavior and a basal drainage system.

Figure of velocity fields of Jakobshaven Isbrae, Greenland. This ice stream is the fastest flowing ice on the planet (From Joughin et al., 2004, Nature)