Evidence for late‐glacial ice dammed lakes in the central strait of magellan and bahía inútil, southernmost south america

Abstract

. This paper critically appraises the evidence for a succession of ice‐dammed lakes in the central Strait of Magellan (c. 53°S) c. 17 000–12 250 cal. yr BP. The topographic configuration of islands and channels in the southern Strait of Magellan means that the presence of lakes provides compelling constraints on the position of former ice margins. Lake shorelines and glacio‐lacustrine sediments have been dated by their association with a key tephra layer from Volcan Reclús (c. 15 510–14 350 cal. years bp) and by 14C‐dated peats. The timing of glacial lake formation and associated glacier readvances is at odds with the rapid and widespread glacier retreat of the Patagonian ice fields further north after c. 17 000 cal. yr bp, suggesting rather that the lakes were coeval with the Antarctic Cold Reversal and persisted to the Late‐glacial/Holocene transition. This apparent asymmetrical latitudinal response in glacier behaviour may reflect overlapping spheres of northern hemisphere and Antarctic climatic influence in the Magellan region.

Retreat of the Cordillera Darwin icefield during Termination I

“…Available evidence from Cordillera Darwin suggests only modest ice advance during the subsequent Antarctic Cold Reversal. Although early reports suggested a major ACR advance to the vicinity of Isla Dawson on the north side of Cordillera Darwin (McCulloch et al, 2005a), sediment cores from Puntas Esperanza and Marinelli are at odds with that interpretation, as they lack any evidence for a readvance following initial deglaciation. The Punta Esperanza bog core, in particular, would have been covered by any ice that advanced north from Cordillera Darwin through Canal Whiteside to Isla Dawson.…”

“…Northern ice flow from Cordillera Darwin is characterized best along a flowline through Canal Whiteside to Bahia Inútil, where numerous, low-relief moraines enclose the eastern end of the bay (Caldenius, 1932;Meglioli, 1992;Clapperton et al, 1995;Bentley et al, 2005;McCulloch et al, 2005aMcCulloch et al, , 2005bEvenson et al, 2009;Darvill et al, 2014). The moraines can be traced southeastward across Isla Grande, where they are thought to correlate with those enclosing the eastern end of Lago Fagnano (Coronato et al, 2009).…”

Assessment of an east-west phenotypic variation in body height, body form and body mass among prehistoric hunter-gatherers of Patagonia and Tierra del Fuego, chile

“…BP) and correspond to terrestrial hunter-gatherers, who lived on the pampas (eastern slopes), and exploited modern and extinct fauna (Bird 1993(Bird , 1946Borrero 2002;Borrero and Martin 2012;Martin et al 2015;Massone 1989Massone , 2004McCulloch and Morello 2005). After the Last Glacial Maximum, a gradual rise in sea levels resulted in a shoreline modification (12,000-8,000 BP) that led to the establishment of modern marine environments (Borrero 1999;McCulloch et al 2005;Morello et al 2012). By 7,000 cal.…”

Geomorphology of marine and glacio-lacustrine terraces and raised shorelines in the northern sector of Península Brunswick, Patagonia, Straits of Magellan, Chile

“…and Glacial stage B (25.2-23.1 ka B.P. ; age from McCulloch, Bentley, Tipping, & Clapperton, 2005). In particular, in the northern sector of the Brunswick Península drumlin direction and lateral-terminal moraine systems indicate that the Seno Otway lobe joined the glacier of the Strait of Magellan adjacent to Segunda Angostura during Glacial Stage A (Darvill et al, 2017;Kilian et al, 2013;Lovell et al, 2011).…”