The landforms and pattern of deglaciation in the Strait of Magellan and Bahia Inu'til, southernmost South America

• Published in: Geografiska Annaler: Series A, Physical Geography
• Main Authors: Bentley, Michael J, Sugden, David E, Hulton, Nicholas R J, McCulloch, Robert
• Other Authors: Durham University, University of Edinburgh, Biological and Environmental Sciences, orcid:0000-0001-5542-3703
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley-Blackwell 2005
• Subjects: Palaeo-environments; Reconstructing Past Environments; Environmental Change; Environmental Geography; Glacial response to climate change; bahía Inútil; Inútil; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/1893/17620; https://doi.org/10.1111/j.0435-3676.2005.00261.x; http://dspace.stir.ac.uk/bitstream/1893/17620/1/Bentley%20et%20al%20313.pdf

We report the results of glacial geomorphological mapping of the Strait of Magellan and Bahía Inútil, southernmost South America. Our aims are to determine the pattern and process of deglaciation during the last glacial–interglacial transition, and to provide a firm geomorphological basis for the interpretation of radiocarbon, cosmogenic isotope and amino acid dates for the timing of deglaciation. The area is important because it lies in a southerly location, providing a link between Antarctica and southern mid-latitudes, and also lies in the zone of the southern westerlies which are a key element in regional climate change. Our mapping shows that it is possible to make a clear weathering and morphological distinction between last glaciation and older landforms and sediments. Within the last glacial deposits we have identified a number of former glacier limits. The key to delineating many of these limits is continuous meltwater channels that run for several kilometres along the outer edge of discontinuous moraine belts. There are four distinct belts of moraines within the deposits of the last glaciation in the central part of the Strait of Magellan. There are two closely spaced major limits (B and C) at the north end of the Strait that reach Punta Arenas airport on the west side, and Península Juan Mazia on the east side. A third limit (D) terminates south of Punta Arenas on the west side, and passes close to Porvenir on the east. In Bahía Inútil there is a more complex pattern with a prominent outer limit (C) and a series of four equally prominent limits (D1 to D4) on both sides of the bay. South of these limits, there is a fourth group of moraine limits (E) on both coasts of the northern end of Isla Dawson, reflecting the last fluctuations of the Magellan glacier before final deglaciation of the southern end of the Strait. There are a number of drumlins within the outer moraine limits. The drumlins are draped by small, younger moraines showing that they have been overridden by subsequent advance(s). The ...