• 责任者：Zhao Shuang (Key Laboratory of Western China’s Environmental Systems ; Ministry of Education ; Research School of Arid Environment ＆ Climate Change ; Lanzhou University ; Lanzhou 730000 ; China) ; Xia Dunsheng
• 刊名：Quaternary Sciences
• 出版年：2013
• 卷期：33(2)
• 关键词：气候 ; climate ; 沙地 ; sandy land ; 内蒙古 ; Inner Mongolia
• 页码：p.283-292
• 图表：illus., 1 table, 66 refs.
• 分类号：1400
• issnNo：ISSN1001-7410
• isbnNo：CN11-2708/P

The Horqin sandy land（42°40＇ - 45°15＇N; 118°30＇ - 124°30＇E） in the western part of Northeast China is located in the present margin of East Asian monsoon zone, and its landscape is sensitive to the climate change. It lies in the transition zoon between the Inner Mongolian Plateau and the Manchurian Plain,with a total area of about 50000km2. This.region is characterized by continental monsoon climate,with a mean annual temperature of 3 -7℃. The mean annual precipitation ranges from ca. 500ram in the southeast to ca. 350mm in the northwest, with about 70% of the rainfall in summer. Stabilized and semi-stabilized sand dunes are widely spread in this region. Sand fields have high sedimentation rates during episodes of sand accumulation period, hence, it is possible that the sand deposits may record short time climatic changes at certain period. However, due to the potential erosion or hiatus, few successive and high-resolution palaeoclimatic sequences of sand deposits have been reported.  This paper present a high-resolution climate evolution record during 4300 - 1000cal, aB. P. derived from sequential aeolian sediments of Liuhutun （ LHT ） section （ 44°28＇N, 123°08＇E ; 151 m a. s. 1. ） in the northeastern frontier of the Horqin sandy land. The 2.96-m sandy paleosol/sandy loess/fine sand section, with a chronological support of 7 radiocarbon dates,has been analyzed at 2-cm intervals（84 -120cm at 4-cm intervals）for grain size distribution（clay,silt, sand contents and Md）, CaCO3 content, organic matter content and environmental magnetic parameters（zlf,XAaM, SIRM et al. ）. Md is considered to represent wind strength and high Md reflects strong winter monsoon winds. CaCO3 content and organic matter content, which denote weathering intensity and the degree of vegetation cover, are chosen as proxies for summer monsoon circulations. The results show that 4300- 3800cal. aB. P. was the warmest and wettest epoch during the study period, with a trend of becoming cooler and drier. The Holocene Optimum in this region is supposed to end at 3800cal. aB. P. Climate between 3800cal. aB. P. and 1700cal. aB. P. was cold and dry, this period can be subdivided into two phases with 3000cal. aB. P. as a boundary. Climate became cooler and drier before 3000cal. aB. P., afterwards the winter monsoon stayed at a strong level while the summer monsoon gradually strengthened. 1700 - 1000cal. aB. P. was a warm and humid period,but the climatic conditions were inferior to the Holocene Optimum. On the millennial scale, our records show an anti-correlation between the strength of summer and winter monsoon. The main trends of climate changes during this period can be compared with stalagmite δ1880 records of the strength of summer monsoon in the South China.  Furthermore, detailed environmental magnetism researches show that the relationship between magnetic susceptibility and environmental factors is complicated, while XARM/XH and XARM/SIRM, which denote magnetic grain size,can be used as paleoclimatic proxies. Because the aeolian magnetic particals have already in a state of stable single domain（SSD）size fractions, XARM//XH and ZARM/SIRM show an inverse correlation with pedogenesis, which are different from pedogenic mechanism of loess-paleosol sequences in the Chinese Loess Plateau.