DETRITAL COSMOGENIC 10BE OF TILL FROM CONTRASTING LANDSCAPES ON HALL PENINSULA, BAFFIN ISLAND: INVESTIGATING THE RELATIONSHIP AMONG MULTIPLE PROXIES OF GLACIAL DYNAMICS

Several relict surfaces, sometimes characterized by pre-glacial or interglacial weathering profiles, have been recognized in core regions of past ice sheets on relatively high plateaus formed on igneous and metamorphic rocks in Scandinavia, Scotland, and Canada. Landscapes with increasing evidence of glacial erosion radiate out of these relict terrains. The latter thus generally transition into landscapes of areal scouring, which are crosscut by landscapes of linear glacial erosion leading to fjords in coastal areas. All of these landscapes have recently been recognized, studied, and mapped across Hall Peninsula using various glacial geology methods including mapping through remote sensing and field work, as well as GIS techniques and till compositional analysis of large mineral exploration industry databases. End-member cold-based and warm-based terrains have been interpreted, as well as more complex transitional terrains or areas where subglacial conditions may have switched from one regime to the other. These interpretations of basal thermal regime and glacial dynamics are now being further tested and developed using detrital ¹⁰Be data obtained from till and regolith sediment on Hall Peninsula. The ¹⁰Be provides an index of spatial variation in glacial erosion, which is then compared to the glacial dynamics interpretation based on all the other proxies including glacial landforms (i.e. elongation and density of streamlined bedrock hills and bedrock depressions/lakes density), occurrence of relict weathered surfaces, and till provenance analysis. The strong relationships among the different proxies suggest the approach will advance our understanding of glacial dynamics and thermal regime histories, especially of more complex transitional terrains.