See more from this Division: Topical Sessions
See more from this Session: The Origin of Mima Mounds and Similar Micro-Relief Features: Multidisciplinary Perspectives
Abstract:
This terrain was deposited in areas where the retreating glacial ice became covered by a comparatively thick blanket of supraglacial drift and therefore melted slowly, allowing hummocks to form and be preserved. The melting of the buried glacial ice is known to have take thousands of years in some areas. During the Holocene, this terrain has undergone moderate post-depositional modification with sediment being eroded from the crests and deposited on the flanks, or for doughnuts, within the central depressions. Multiple weathering horizons have been documented within this sediment.
Another hummocky terrain unit is composed entirely of glaciolacustrine sediment. The relatively low relief phases of these landforms are referred to as humpies. Their genesis is generally due to deposition of glacial lake sediment over grounded glacial ice which subsequently melts to produce the hummocky/doughnut terrain. In some areas, it is proposed that they may also be a product of rapid permafrost development in recently drained glacial lakes under periglacial environments, which subsequently disintegrated during the early Holocene.
See more from this Division: Topical Sessions
See more from this Session: The Origin of Mima Mounds and Similar Micro-Relief Features: Multidisciplinary Perspectives