The Newfoundland Ice Sheet, Canada, reconstructed using a glacial geological inversion approach and cosmogenic exposure dating.

As ice sheets are sensitive barometers of global climate change, reconstructing palaeo-ice sheets provides important insights into how contemporary ice sheets may respond to future climate change. The Newfoundland Ice Sheet (NIS) is of particular significance in this regard. It was located on the fringes of the Atlantic Ocean and the Laurentide Ice Sheet (LIS). This suggests the NIS was likely influenced by a number of external and internal drivers, including configuration changes in the LIS, ice stream activity, fluctuations in sea level and oceanic circulation and climate signals from the wider Amphi-North Atlantic. Therefore Newfoundland is a key location for investigating how ice sheets may respond to a number of forcing mechanisms. An established technique used to reconstruct ice sheets is the mapping and spatial analysis of glacial landforms. This record can be used to establish relationships between ice sheet behaviour and a range of forcing mechanisms. Here we present new mapping based on our interpretation of SPOT satellite imagery, Digital Elevation Models and bathymetric imagery of Newfoundland. Our new database of ~150,000 individually mapped subglacial bedforms of glacial lineations and ribbed moraines significantly increases the known landform record in this region. We report our attempt at unravelling this record using a glacial inversion approach and flowset analysis, which separates ice flow patterns into snapshots of ice sheet events. Initial analysis indicates the NIS was dynamic and susceptible to configuration changes throughout the last glacial cycle including ice divide migration, regional configuration changes, ice stream activity and enhanced ice flow caused by marine drawdown. To enable greater radiometric control of the deglacial behaviour of the NIS, we report new cosmogenic exposure ages from several sites around southeast Newfoundland. These new exposure ages will be combined with existing cosmogenic records across Newfoundland to help temporally constrain our ice sheet reconstruction.