Journal of Geography  & Natural Disasters
Acesso livre

Abstrato

Deformation styles and sedimentology criteria to distinguish between subglacial, glaciotectonic and glaciomarine sedimentation of glacial Lake Agassiz

Afsoon Kazerouni,

Glaciolacustrine sediments accumulated in vast lake systems of central and eastern North America. The central region included glacial Lake Agassiz, one of the largest fresh-water lakes that every existed. Lake Agassiz covered during different phases most of Manitoba, and parts of Saskatchewan, Ontario, North and South Dakota, and Minnesota. Overflow from Lake Agassiz and other large proglacial lakes cut spectacular spillway channels across the northern Great Plains. The southern part of the Lake Agassiz basin contains a complex of sediments that reflects the first 2000yr of the lake's history. This research compares and contrasts the sedimentology and structural geology of a Glaciolacustrine sediments site (glacial Lake Agassiz). Primary studies suggest that the glaciomarine environment is dominated by sedimentary processes, related to sediment supply, water content and distance from the glacier margin. Glaciotectonic deformation, however, is dominated by deformational processes, related to effective pressure, shear strain, nature of the subglacial material and distance from the glacier margin. From this study a series of criteria will be suggested to distinguish both Quaternary and contemporary glaciotectonic and glaciomarine environments. In addition, the investigation also discusses the subsequent effects of glaciotectonic deformation on a primary glaciomarine site due to a glacial readvance.