Chronology of the Late Cenozoic Patagonian glaciations and their correlation with biostratigraphic units of the Pampean region (Argentina)

A single Mid-Pleistocene long-distance dispersal by a bird can explain the extreme bipolar disjunction in crowberries ( Empetrum )

“…The GPG was followed by four major glaciations (20) during the Middle and Late Pleistocene, the last having its maximum between 19,000 and 23,000 y ago (22). The upper age constraints for the end of the Danaglacial/post-GPG 1 (0.76 Ma) and the Gotiglacial/post-GPG 2 and 3 [0.065 Ma (20)] fit well with our estimated median ages for southern hemisphere Empetrum.…”

“…Starting in the Late Miocene, southern Patagonia and Tierra del Fuego were heavily glaciated several times (20). The Patagonian Andes and the eastern piedmont areas between 36°S and 56°S were almost completely covered by a continuous ice sheet, the Great Patagonian Glaciation (GPG), with ice tongues reaching the Atlantic coast south of Río Gallegos (~51°S) toward the end of the Early Pleistocene (20,21). The GPG was followed by four major glaciations (20) during the Middle and Late Pleistocene, the last having its maximum between 19,000 and 23,000 y ago (22).…”

“…The Patagonian Andes and the eastern piedmont areas between 36°S and 56°S were almost completely covered by a continuous ice sheet, the Great Patagonian Glaciation (GPG), with ice tongues reaching the Atlantic coast south of Río Gallegos (~51°S) toward the end of the Early Pleistocene (20,21). The GPG was followed by four major glaciations (20) during the Middle and Late Pleistocene, the last having its maximum between 19,000 and 23,000 y ago (22). The upper age constraints for the end of the Danaglacial/post-GPG 1 (0.76 Ma) and the Gotiglacial/post-GPG 2 and 3 [0.065 Ma (20)] fit well with our estimated median ages for southern hemisphere Empetrum.…”

Insight into the latest Messinian (5.7–5.2Ma) palaeoclimatic events from two deep-sea Atlantic Ocean ODP Sites

“…Moreover, high-resolution data from sediment cores obtained from multi-sensor studies suggest orbitally controlled size variations of the Antarctic Ice sheet in the late Miocene (Grutzner et al, 2003). Further afield, evidence for several glacial episodes is found in Patagonia between 7 and 5 Ma (Rabassa et al, 2005). These observations are also consistent with major coeval changes in deep oceanic circulation recorded in sediments in the Argentine basin (Ledbetter and Bork, 1993;Hernandez-Molina et al, 2006) and thought to be related to episodic changes in Antarctic Bottom Water (AABW) flow.…”

Can glacial erosion limit the extent of glaciation?

“…From 40ºS to 55ºS latitude, moraines and till sheets clearly show that glacial expansions have been less extensive in general since the GPG, at 1.1 Ma (Caldenius, 1932, Rabassa andClapperton, 1990;Mercer, 1983;Meglioli, 1992;Singer et al, 2004a;Coronato et al, 2004a;Rabassa et al, 2005). Lava flows interbedded with glacial deposits allow a multi-chronologic approach to dating the record; radioisotopic and cosmogenic nuclide data provide quantitative ages on at least a broad chronologic framework for the last 1 Myr (Singer et al, 2004a, b;Kaplan et al, 2005).…”