A geochemical approach to glacial sediment provenance in Northern Ireland

Reconstruction of flow patterns for the Irish Ice Sheet has traditionally relied heavily on the interpretation of subglacial bedforms, namely ribbed moraines and drumlins. Recent research has demonstrated the interpretation of these landforms may at times be misleading, particularly over small sample areas. Furthermore not all areas of glaciated terrain experienced or retain evidence of a
bedforming event. An alternative approach independent of bedform presence is to use geochemistry to establish glacial sediment provenance and hence ice flow direction. This project has used geochemistry of soil developed on till to investigate glacial sediment provenance in Northern Ireland. Principal Component Analysis has been applied to the Tellus Survey soil geochemical database for samples taken on areas of till superficial geology in the region. This approach
allows identification of groups of chemical elements that can be linked to likely parent bedrock material for the till. The regional results show glacial transport and that the majority of till deposits in Northern Ireland are closely related to local bedrock, with rapid geochemical changes at lithological boundaries. This suggests till transport rates in this sector of the Irish Ice Sheet were low, with rapid entrainment and low evacuation rates of debris to the ice margin.