Asynchronous glacier dynamics during the Antarctic Cold Reversal in central Patagonia

Glacier expansion in central Patagonia during the Antarctic Cold Reversal followed by retreat and stabilisation during the Younger Dryas

“…Here, advances of the Tranquilo and Calluqueo glaciers were dated at 13.8 ± 0.5 ka and 13.2 ± 0.2 ka, respectively, coeval with the ACR (Fig. 2;Sagredo et al, 2018;Davies et al, 2018). At this time, the Calluqueo glacier calved into a palaeolake, and part of the moraine was subaqueous (Davies et al, 2018).…”

“…Following disintegration of the Lago Puyerredón lobe, ice on the northern and western flanks of San Lorenzo was largely confined to the mountain valleys (Davies et al, 2018;Martin et al, 2019;Sagredo et al, 2018). Here, advances of the Tranquilo and Calluqueo glaciers were dated at 13.8 ± 0.5 ka and 13.2 ± 0.2 ka, respectively, coeval with the ACR (Fig.…”

“…2;Sagredo et al, 2018;Davies et al, 2018). At this time, the Calluqueo glacier calved into a palaeolake, and part of the moraine was subaqueous (Davies et al, 2018). YD stabilisation is suggested by a couple of exposure ages from inset moraines in both valleys (Fig 2; 12.5 ± 0.4 and 11.6 ± 0.4 ka in the Tranquilo valley (Sagredo et al, 2018), and 12.9 ± 0.8 and 12.0 ± 0.5 in the Salto valley (Glasser et al, 2012)).…”

“…Glacier advances/stillstands during the ACR (Sagredo et al, 2018;Davies et al, 2018;Nimick et al, 2016) as well as YD (Sagredo et al, 2018;Glasser et al, 2012;Nimick et al, 2016) have been reported east of the Northern Patagonian Icefield and on the north-western flanks of Monte San Lorenzo. Many of these glaciers calved into a large regional palaeolake during most of the LGIT (Davies et al, 2018;Thorndycraft et al, 2019), and this process together with topographic pinning points on the ice bed likely exerted a strong influence on their dynamics and response to cold reversals (Davies et al, 2018). In addition, many exposure ages from moraine boulders previously interpreted as dating YD advances (Glasser et al, 2012), are considered erroneously young as a consequence of their submergence in a palaeolake (Thorndycraft et al, 2019).…”

The glacial geomorphology of the Río Corcovado, Río Huemul and Lago Palena/General Vintter valleys, northeastern Patagonia (43°S, 71°W)

“…The Patagonian region of southern South America was host to the most extensive Quaternary ice sheet of the southern hemisphere outside of Antarctica, the Patagonian Ice Sheet (PIS). The PIS covered a latitudinal extent of ∼2000 km (38°S-56°S; Figure 1) along the spine of the Patagonian and Fuegian Andes (Caldenius, 1932;Davies et al, 2018Davies et al, , 2020Martínez et al, 2011). Patagonia is part of the only continental landmass that fully intersects the precipitationbearing southern westerly winds (Garreaud et al, 2013) and is one of few regions in the southern mid-latitudes containing a well-developed Quaternary glacial geomorphological record (Clapperton, 1993;.…”