Discrepancies in dating the expansion of European glaciers during the Last Glacial Cycle

Abstract

One of the most important problems in glacial geomorphology is the disagreement regarding the dates of glacial advances. During the Last Glacial Maximum (LGM, ~29 to 19 ka), the generalised advance of mountain glaciers coincided with the greatest extent of ice in the large ice sheets of northern Europe and North America and with the lowest sea level during the Last Glacial Cycle (∼110 to 11.7 ka). The significant number of studies dealing with glacial chronologies during recent decades and improvements in dating techniques have provided a wide range of information about the evolution of European glaciers and the timing of major glacial advances that deposited different types of moraines, proglacial sediment (especially fluvioglacial and kame terraces, and sandar), and glaciolacustrine sediment. Several publications have synthesized data on the evolution of European glaciers as a starting point for analysis of synchronous or asynchronous patterns regarding the dates of glacial advances in European ice sheets and mountain glaciers. Thus, studies of the significant glacial advances during MIS 5, MIS 4, and MIS 3 have reported disparate dates, so available information only provides an incomplete understanding of the expansion of European glaciers. Some of these discrepancies were significant, such as the occurrence of advances at the end of MIS 3 in some mountains of southern Europe while the ice sheet occupied a very small area in the Scandinavian Peninsula. Other dating discrepancies, such as events during the LGM and the Oldest Dryas (Heinrich Stadial 1), are smaller but still relevant. The possible causes of these discrepancies include climatic differences between northern and southern Europe, the importance of local topographic factors, and the variety of dating techniques. This review does not include the Younger Dryas Stadial, because the short duration of this cold period does not reflect the occurrence of large disparities in the timing of glacier advances, and also because of the uncertainty ranges of the datings overlap with the onset of the Holocene and the end of the Bølling-Allerød.