腾格里沙漠南缘土门剖面末次间冰阶层段的粒度特征及其反映的气候-沉积环境

腾格里沙漠南缘土门剖面末次间冰阶层段（TMS 3）由风成砂、黄土状亚砂土、砂黄土、古土壤、湖相沉积物和冲积黄土等6种沉积相相互叠覆构成。粒度分析结果显示，该层段以砂质沉积物为主，粉砂次之，黏土最少，平均值分别为65.45%、26.72%和8.83%；在砂粒级中，以细砂含量最高，其次为极细砂，其余为中砂-粗砂颗粒。粉砂含量、黏土含量、M_z和σ在风成砂中呈现谷值，在其他沉积相为峰值，中砂-粗砂和细砂则相反。粒度指标指示腾格里沙漠南缘土门剖面末次间冰阶至少经历了13次暖湿和12次冷干的气候波动，且可划分为TMS 3e（54 200~59 750 a BP）、TMS 3d （54 200~40 800 a BP）、TMS 3c （40 800~32 800 a BP）、TMS 3b （32 800~25 400 a BP）和TMS 3a （25 400~22 940 a BP）等5个亚段， 25次冷暖波动与格陵兰冰芯和中国南方石笋记录的D/O事件以及北大西洋深海沉积物记录的H事件具有很高的同步性。

Grain Size Characteristics and Sedimentary Environment of the Tumen Section in Southern Tengger Desert during the Interstadial of the Last Glacial

The MIS 3 sequence of Tumen Section (TMS 3) in the southern margin of Tengger Desert was composed by paleo-aeolian sand,loess-like sandy loams,sandy loess,paleosoil,lacustrine and alluvial loess.The results of grain size analysis showed the sand contents were dominants,silty sand contents were in second place,and clay contents were minimal in TMS 3,and their contents in average are 65.45%,26.72% and 8.83%,respectively;based on the sequence decreasingly in content,the sand contents can also be divided three portions,and they are fine sand,very fine sand and medium sand-coarse sand.The contents of medium sand-coarse sand and fine sand in paleo-aeolian sands were higher than other 5 sediments in TMS 3.These grain size cycles indicated the climate during MIS 3 in this area at least went through 13 warm-wet events and 12 cold-dry events and could divided into five substages:TMS 3e (54 200-59 750 BP),TMS 3d (54 200-40 800 BP),TMS 3c (40 800-32 800 BP),TMS 3b (32 800-25 400 BP) and TMS 3a (25 400-22 940 BP).These fluctuations show a strong coherence with D/O events recorded in Greenland ice core and southern China stalagmites,as well,H events recorded in North Atlantic sediments.