The nature and timing of landscape change at Cerro Benítez, Última Esperanza, southern Patagonia (52°S): New insights into the history of megafaunal extinctions and human occupation

Holocene hydroclimate variability along the Southern Patagonian margin (Chile) reconstructed from Cueva Chica speleothems

“…4) signify reduced infiltration and less favourable conditions for intensive calcite precipitation in the cave. Local pollen data confirms our interpretation of drier conditions at the time (McCulloch et al, 2021).…”

“…Some areas are covered by open grassland and peat vegetation. It is noteworthy that the catchment of the cave is downstream the Vega Benitez peat bog (McCulloch et al, 2021). Fig.…”

Late Glacial and Holocene Palaeolake History of the Última Esperanza Region of Southern Patagonia

“…New data from Lago Pato are consistent with the timing of 1) forest expansion in and around Última Esperanza from c. 11.9 cal ka BP onwards (Moreno et al, 2012;Moreno and Videla, 2016;Moreno et al, 2018;McCulloch et al, 2021;Moreno et al, 2021); 2) regional fjord deglaciation (Bertrand et al, 2017); and 3) regional pollen and lacustrine records from 52 to 55 °S (Zolitschka et al, 2018;McCulloch et al, 2020;Moreno et al, 2021). Increasingly arid conditions (linked to falling lake levels) have been found in several early Holocene terrestrial records from Southern Patagonia (Moreno et al, 2012;Zolitschka et al, 2013;Moreno et al, 2018;Zolitschka et al, 2018;Reynhout et al, 2019;McCulloch et al, 2020;Moreno et al, 2021) and in the wider sub-Antarctic region, for example, Macquarie Island at 54 °S in the Southern Ocean (Saunders et al, 2018) (Figures 10C,F,G,I,J).…”

“…Several lines of evidence support Units 2-5A being missing from the LP08 record: 1) the lack of pollen from a cold-steppe scrubland environment and the existence of an already established open landscape with a Nothofagus forest (comprising ~30% of TLP) around Lago Pato; 2) the existence of a benthic diatom community in organic sediments of Unit 5B that were deposited unconformably on top of Unit 1 glacial sediments; 3) the presence of shallow-water sub-aquatic angiosperm Myriophyllum sp., an early coloniser in organic deposits <10 ka (Unit 5 in LP08); and 4) the absence of two substantial Volcan Reclus tephras dated to 9,320 ± 15 14 C yr BP (10,570-10,300 cal a BP) in the basal glaciolacustrine unit in a record from nearby Lago Eberhard (Moreno et al, 2012) and other lake records in the Última Esperanza region (Sagredo et al, 2011) and the R1 tephra dated to 12,627 ± 48 14 C a BP (15,,610 cal a BP) (Sagredo et al, 2011). The latter is >20 cm thick in the Cerro Benitez area ~31 km S of Lago Pato (McCulloch et al, 2021), and the presence in lacustrine deposits indicates that ice had thinned to at least ~215 m a.s.l. by 17.5 ka (Sagredo et al, 2011).…”

“…Successive palaeolake lowering after the g-LGM occurred sometime before c. 17 ka during Stage I of the Cordillera Paine glaciation scheme (García et al, 2014;García et al, 2018) and after glacial advance stages C and D in the Strait of Magellan that ended between c. 21.7-20.4 ka and c. 17 ka (McCulloch et al, 2005). The oldest minimum radiocarbon ages for ice retreat and the formation of ice-dammed lake deposits in the Lago Sofia-Puerto Consuelo valley area are c. 18-17 cal ka BP (Sagredo et al, 2011;McCulloch et al, 2021) (Figure 2).…”