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Permafrost aggradation followed by brutal degradation during the upper pleniglacial in Mongolia: the probable response to the H2 Heinrich event at 21 kyr BP
Author(s) -
Bertran Pascal,
Fontugne Michel,
Jaubert Jacques
Publication year - 2003
Publication title -
permafrost and periglacial processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.867
H-Index - 76
eISSN - 1099-1530
pISSN - 1045-6740
DOI - 10.1002/ppp.435
Subject(s) - aggradation , geology , permafrost , physical geography , horizon , loess , climatology , geomorphology , paleontology , structural basin , oceanography , fluvial , geography , physics , astronomy
Upper pleniglacial loess and slope deposits in Europe frequently show an intensely cryoturbated gley horizon used as a stratigraphic benchmark level (the Nagelbeek Tongue Horizon). An equivalent horizon has been found in Mongolia, suggesting that it may characterize the whole Eurasiatic continent between latitudes 45° and 50° north. This horizon reflects a very cold episode marked by the aggradation of permafrost, followed by a sudden warming and a probable increase in snowfall, that gave rise to permafrost degradation. The latter episode is indicated by cryoturbation on gentle slopes and plug‐like solifluction or active‐layer sliding on steeper slopes. We correlate these processes to the Heinrich H2 cold event at ca. 21 kyr 14 C BP and the following interstade that has been recognized in high‐resolution ice and marine records. Copyright © 2003 John Wiley & Sons, Ltd.