The Origin of Bedrock Megagrooves in Glaciated Terrain
Supervised by Dr David Evans, Dr Dave Roberts & Dr Chris Stokes
This project aims to provide a better understanding of the production of bedrock megagrooves. Various (often radically different) hypotheses exist as to how these features form, including one which suggests that they are ancient forms that are perpetuated by ice erosion during subsequent glaciations and that initiation can be explained only by bedrock and regolith characteristics inherited by the early Quaternary glaciations. This involves gouging by boulders inherited from pre-Quaternary regolith residues. Research questions that relate to wider scale palaeoglaciological issues include: a) are megagrooves indicative of fast flow?; b) is megagroove location related to bedrock structure; and c) do megagrooves, once formed, dictate the location of lineation deepening during the late Quaternary rather than ice stream location in ice sheets? In order to test these various hypotheses and questions the successful student will investigate the geographical distribution of megagrooves, their morphology and relationships to bedrock types and structures and long term denudation histories. Other specific aspects that need to be addressed with respect to megagrooves are groove spacing, depth and alignment, specific characteristics that have previously escaped in depth analysis. Such data can then be employed in an attempt to scale up the characteristics of minor erosional forms, such as striae, chattermarks and gouges, in order to assess similar process-form relationships at different scales. Applicants are expected to have a general understanding of glacial landforms and their application to palaeoglaciological reconstruction and experience of remote sensing, aerial photograph analysis, GIS and field-based surveying and analysis of glacial deposits may be advantageous. Potential field sites include NW Scotland, Northern Iceland and the Mackenzie Valley of NW Canada.