Mid-Quaternary Glaciations in the Southern Hemisphere

CORONATO, A.; RABASSA, J.

Encyclopedia of Quaternary Science

Elsevier

Lugar: Amsterdam; Año: 2007; p. 1051 - 1057

The Mid-Quaternary glaciations in the Southern Hemisphere are poorly known, due to the relative lack of emerged lands in an ocean-dominated hemisphere and to the technological problems of absolute dating during this period. The Patagonian glacial sequence in Southern Argentina is the most complete and relatively well-dated in the hemisphere, with 2-3 major glaciations and several stages depicted by extensive morainic arcs. Some of these units are inter-bedded with lava flows, which have allowed their 40Ar/39Ar dating and paleomagnetic studies. Erratic boulders on the youngest moraines of this period (Late Illinoian/Riss) have been dated by cosmogenic isotope dating techniques. Their age is estimated as extending over the Marine Isotope Stages (MIS) 6 to 22-26 (?). All the Mid-Quaternary glaciations were smaller than the most extensive glaciation (“Great Patagonian Glaciation”, GPG), which took place probably during MIS 30-34 (Early Pleistocene). Other areas with glaciations with the same age are the Northern and Central Andes, Tropical Africa, Tasmania, New Zealand and Antarctica and several subantarctic islands, but their record is generally poorly dated.