Extent and chronology of Quaternary glaciation

Abstract

In a recent INQUA project the extent of Pleistocene glaciations has been digitally mapped and the chronology of events reviewed. The onset of the present Ice Age in both hemispheres dates back to the Palaeogene. In Greenland, Iceland, North America and southernmost South America sizeable ice sheets formed well before 2.6 ka BP. In Alaska and on Tierra del Fuego the ice advanced further than in any later glaciations. Evidence for Early Pleistocene glaciation (2.6-0.78 Ma) has been reported from many parts of the world, but in most cases dating remains problematic, and the size of the glaciers and ice sheets is unknown. A number of Middle Pleistocene glaciations (0.78-0.13 Ma) have been identified, mostly correlated with MIS 16, 12 and 6, including the Donian, Elsterian and Saalian of Europe. The extent of the MIS 6 glaciations is well known. Especially in Eurasia the extent of the Late Pleistocene (0.13 Ma to present) glaciations had to be revised. Major ice advances are reported for 80-100 ka BP, c. 70-80 ka BP and c. 20 ka BP, with the earlier glaciations being most extensive in the east. The very different shapes of the ice sheets-Donian vs Elsterian, Early vs Late Weichselian -are as yet difficult to explain and remain a challenge for climatic modellers.