Start date:
November/ December
End date:
Blue Glacier
Principle Investigator:
Sean Fitzsimons
University of Otago
Dunedin, New Zealand
This proposal describes research that will advance our understanding of thermal, and mechanical processes that define the entrainment, transfer and deposition of sediment beneath and at the margins of ice shelves. Ice shelf moraines are form where floating glacier ice flows onto land and deposits marine sediment that usually contains biological material that can be dated. However, dating organic material that is preserved within ice shelf moraines is not a straight forward proposition because the death of marine organisms is not directly related to timing of moraine formation. Previous studies of debris entrainment within ice shelves and a reconnaissance study undertaken at the edge of the McMurdo Ice Shelf suggest that are deficiencies in our current understanding of the thermal, mechanical and deformation processes associated with ice shelves. We do not yet have a secure conceptual framework for understanding radiocarbon dates from marine organisms preserved within ice shelf moraines. Such a framework is a prerequisite for reliable and accurate glaciological or climatic reconstructions. The research proposed here is designed to add to our understanding of ice shelf moraine formation by relating ice shelf themodynamics to sediment entrainment and transportation processes. This proposal builds on our past research on sediment transfer in cold-based glaciers in the McMurdo Dry Valleys by focussing on water and sediment accretion processes beneath floating ice. The objective of the proposed research is to develop an understanding of the entrainment, transfer and deposition of sediment by ice shelves. The outcome will be the development of a model for the accretion and transfer of ice and debris in ice shelves and a glaciological basis for palaeoclimatic reconstructions derived from ice shelf moraines. Defining the glaciological basis of ice shelf moraine formation is essential to understanding the age and chronology of ice shelf moraines, which are widely used to reconstruct the timing and magnitude of Late Pleistocene ice advances. We propose to achieve these objectives by undertaking an integrated study of the entrainment, transfer, deposition and deformation of sediment adjacent to the margin of a thin, partly grounded ice shelf (the McMurdo Ice Shelf).