A glacial geomorphological map of the Seno Skyring-Seno Otway-Strait of Magellan region, southernmost Patagonia

Abstract

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This paper presents a detailed glacial geomorphological map covering over 16,000 km of the Seno Skyring-Seno Otway-Strait of Magellan region in southernmost Patagonia. It builds on previously published maps produced at a variety of scales and is re-mapped in detail for the purposes of reconstructing the pre-Last Glacial Maximum (LGM) glacial dynamics of the region, with particular focus on deciphering the glacial landsystem north east of Seno Otway, which has been postulated as a zone of ice streaming. Additional areas of interest include the reconstruction of proglacial lakes dammed by the Skyring and Otway lobes; their drainage during various stages of retreat; and a landsystems approach to the overall reconstruction of the combined Skyring-Otway-Magellan ice lobes. Mapping was conducted using a combination of Landsat ETM+ and ASTER satellite imagery and oblique and vertical aerial photographs, and is centred on approximately 53_S, 71_W. Seven main landform types have been mapped: glacial lineations, moraines, meltwater channels, irregular dissected ridges, eskers, outwash plains and former shorelines. The map records several episodes of ice flow, as revealed by glacial lineations, with the area around Laguna Cabeza del Mar exhibiting spectacular elongate drumlins. Drumlin fields are associated with three major ice lobes whose extent is marked by a series of moraine ridges and lateral meltwater channels. Large parts of the area were also subjected to proglacial meltwater erosion and deposition, as recorded by large tracts of outwash and associated channels.