干旱区生态环境知识资源中心

We present a high-resolution reconstruction of vegetation and environmental changes from a 40-m thick section in the western part of the Chinese Loess Plateau in attempt to reveal the details of the MIS 2 and MIS 1 climate variations. Our data show that a desert steppe occupied the landscape between similar to 24,500 and similar to 13,600 C-14 yr BR Two episodes of further vegetation deteriorations occurred between similar to 20,000 and similar to 17,100 C-14 yr BP and between similar to 15,100 and similar to 13,600 C-14 yr BP, corresponding to the Heinrich events 2 and 1. The late glacial stage between similar to 13,600 and similar to 9880 C-14 yr BP included four sub-stages that correspond chronologically and climatologically to the European deglacial sub-stages. The first sub-stage (similar to 13,600 to similar to 12,400 14C yr BP) corresponds to the Boiling warm period; the second sub-stage (similar to 12,400 to similar to 11,500 C-14 yr BP) to the Older Dryas cold period; the third sub-stage (similar to 11,500 to similar to 10.700 C-14 yr BP) to the Allerod warm period: and the fourth Sub-stage (similar to 10,700 to similar to 9880 C-14 yr BP) to the Younger Dryas cold period. The early-mid Holocene (similar to 9880 to similar to 4370 C-14 yr BP) was a period when a forest steppe dominated the landscape under a warm and wet climate. During this period, eight cool and dry spells occurred at similar to 9720 C-14 yr BP (E1), similar to 9380 C-14 yr BP (E2), similar to 8870 C-14 yr BP (E3), similar to 8660 C-14 yr BP (E4), similar to 8440 C-14 yr BP (E5), similar to 8240 to similar to 8060 C-14 yr BP (E6), similar to 7120 to similar to 6550 C-14 yr BP (E7), and similar to 5640 to similar to 5120 C-14 yr BP (E8). After a major deterioration in vegetation between similar to 4370 to similar to 3270 C-14 yr BP, the study area experienced improved moisture conditions between similar to 3270 to similar to 1450 C-14 yr BP, followed by a persistent deterioration of vegetation under a drying climate during the past similar to 1500 years. (C) 2009 Elsevier B.V. All rights reserved.