Quaternary International 136 (2005) 25–32 Lacustrine and eolian records of Holocene climate changes in the Mongolian Plateau: preliminary results Z.-D. Feng a,b,Ã , W.G. Wang a , L.L. Guo a , P. Khosbayar c , T. Narantsetseg c , A.J.T. Jull d , C.B. An a , X.Q. Li a , H.C. Zhang a , Y.Z. Ma a a National Laboratory of Western China’s Environmental Systems, MOE, Lanzhou University, Lanzhou 730000, China b Department of Earth and Environmental Studies, Montclair State University, Upper Montclair, NJ 07043, USA c Institute of Geology and Mineral Resources, Mongolian Academy of Sciences, Ulaan Baatar 210351, Mongolia d NSF Arizona AMS Laboratory, University of Arizona, Tucson, AZ 85721, USA Available online 19 January 2005 Abstract 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 14 C dated and the interpolated ages, the following observations can be made. In the northern Mongolian Plateau, a best developed Holocene paleosol dated at 8672 14 CyrBP 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 14 CyrBP). By contrast, in the northern Mongolian Plateau the most humid conditions seem to have occurred from 4500 to 2500 (possibly to 1650) 14 CyrBP. 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. r 2004 Elsevier Ltd and INQUA. All rights reserved. 1. Introduction Possible human-induced climate change and adverse human impacts on environment alert us to assess the future climatic stability and environmental sustainabil- ity. However, this assessment requires a solid under- standing of the natural climatic variability on different time scales. The Holocene is of particular interest in that regard because the climatic boundary conditions are similar to those experienced now and possibly in the near future. Of a special and most likely global significance to the Holocene climatic history is the traditionally defined Maximum Postglacial Warmth event (Winkler and Wang, 1993) when large-scale climatic systems were interpreted to have reorganized (Stager and Mayewski, 1997; Steig, 1999). Its onset has been variously placed at 10,000–7500yrBP and its end at 5000–2000yrBP (An et al., 2000). The Maximum Postglacial Warmth was reported to have occurred synchronously between 8500 and 3000yrBP across east–central Asia with the climax (equivalent to the Climatic Optimum defined by An et al., 2000) from 7200 to 6000yrBP (Shi et al., 1994a,b). However, An et al. (2000) recently argued that the Climatic Optimum was time-transgressive from northwest to the southeast in the summer monsoon-influenced area of China (i.e. eastern China). To understand the global Holocene climate changes and the controlling mechanisms, temporal and spatial ARTICLE IN PRESS 1040-6182/$-see front matter r 2004 Elsevier Ltd and INQUA. All rights reserved. doi:10.1016/j.quaint.2004.11.005 Ã Corresponding author. National Laboratory of Western Chinas Environment Systems, Lanzhou University, MOE, Lanzhou 730000, China. Tel: +869736557811; fax: +869736554390. E-mail address: fengzd@lzu.edu.cn (Z.-D. Feng).