MORPHOMETRY OF GLACIGENIC LAKES IN NORTH AMERICA

Glaciation has extensive impacts on landscape evolution past, present, and future. Inactive (paleo) and actively-forming glacigenic lakes provide insight on glacial history, valuable resources and, in some cases, hazards to nearby human populations. Both proglacial and subglacial lakes are potentially significant in influencing ice-sheet dynamics by way of, for example, subglacial lake drainage and proglacial lake ice-sheet instability. However, investigations of continent-wide and ice-sheet-wide analyses of glacigenic lake characteristics, such as shape and spatial distribution, are lacking. The geomorphologic record of deglaciated landscapes provides a tool to assess and compare the morphometry of negative-relief lakes (i.e., within basins) beneath and at the margins of the relict Cordilleran and Laurentide ice sheets. Using publicly available datasets of millions of North American lakes, this work examines characteristics, including surface area, perimeter, shoreline development, and shoreline density, of paleo-subglacial and active proglacial lakes. We consider regional geology, topography, surrounding landform assemblages, latitude, and glacial history as factors possibly associated with glacial hydrology and/or glacial behavior (i.e., terminus position and ice flow). Preliminary results from select regions in eastern and northwestern Canada suggest latitudinal controls on the distribution of exceptional perimeter-to-area ratios. Furthermore, both lake morphometry and total area exhibit spatial patterns related to bedrock geology, suggesting an important influence of substrate on glacigenic - in this case, subglacial - lake development. This work aims to explore spatial patterns of lake characteristics in the context of the regional landscape and glacial behavior, findings of which will provide insight to glacial hydrology of contemporary ice sheets. The large-scale geomorphic approach in deglaciated landscapes highlights the utility of approaching outstanding questions in landscape evolution and glaciology by merging morphometric data with qualitative landscape and glacial history information within a statistical framework.