Lacustrine and eolian records of Holocene climate changes in the Mongolian Plateau: preliminary results

This study compares two pairs of adjacent lacustrine and eolian sections at sites in the southern and northern Mongolian Plateaus in order to test spatial climate variability during the Holocene. Based on the lithology, proxy data, and 14C dated and the interpolated ages, the following observations can be made. In the northern Mongolian Plateau, a best developed Holocene paleosol dated at 8672 14C yr BP at the Shaamar section and the carbonate-rich laminated layer in the Gun Nuur lake core mark the interval of warmer and dryer climate during the early Holocene. Younger paleosols at the Shaamar section and corresponding organic-rich layers in the Gun Nuur core were formed under distinctly cooler and more humid conditions. The Baahar Nuur lake core in the southern Mongolian Plateau and the Dingxi-type section in the northern part of the Western Chinese Loess Plateau appear to indicate that a prolonged interval of maximum humidity prevailed in this region during the early and mid-Holocene (9000-4000 14C yr BP). By contrast, in the northern Mongolian Plateau the most humid conditions seem to have occurred from 4500 to 2500 (possibly to 1650) 14C yr BP. This discrepancy implies that the concept of the Holocene climatic optimum has limitations and may have to be reconsidered if it is intended to have a large-scale connotation.