A Glacier through a Grain of Sand: Sediment Micromorphology from a Land-Terminating Glacier in West Greenland

Abstract

Isunnguata Sermia is a land terminating glacier in West Greenland with prominent upwellings of subglacial water in the outwash plain. Sediment that is suspended in the upwelling water is preserved in ice, creating a window into the subglacial environment. The presence of certain established microtextures, such as those caused by fluvial or high-stress processes, is indicative of a grain’s impact and transport history. Scanning electron microscopy (SEM) imaging of quartz sand grains is used to analyze this micromorphology. Across sand grains collected from different glacial depositional environments and the frozen subglacial water of Isunnguata Sermia, the microtexture distributions are extremely similar despite their different transport processes. While this may represent the limitations of microtexture analysis, it also suggests a high degree of sediment recycling in a basin that includes both the subglacial and the proglacial environment.