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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、Mz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 750aBP)、TMS 3d(54 200~40 800aBP)、TMS 3c(40 800~32 800aBP)、TMS 3b(32 800~25 400aBP)和TMS 3a(25 400~22 940aBP)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。
The last interglacial interval (TMS 3) of the Tumen section in the southern margin of the Tengger Desert overlaps with six sedimentary facies including aeolian sand, loessial sandy soil, sandy loess, paleosol, lacustrine sediments and alluvial loess constitute. The results of particle size analysis showed that the sediments are mainly sandy sediments, followed by silt, with the least amount of clay, with the average values of 65.45%, 26.72% and 8.83% respectively. Among the sand grades, the content of fine sand is the highest, followed by Very fine sand, the rest of the sand - coarse sand particles. The silt content, clay content, Mz and σ show valleys in the aeolian sand and peak values in the other sedimentary facies, while the middle sand - grit and fine sand are the opposite. The grain size index indicates that the last intercropping of the Tumen section in the southern margin of the Tengger Desert has undergone at least 13 warm and 12 cold cycles of climatic fluctuations and can be divided into TMS 3e (54 200-59 750 aBP), TMS 3d 54 200 ~ 40 800aBP), TMS 3c (40 800 ~ 32 800aBP), TMS 3b (32 800 ~ 25 400aBP) and TMS 3a (25 400 ~ 22 940aBP) D / O events recorded by the stalagmite in southern China and H events recorded in the deep-sea sediments of the North Atlantic have a high degree of synchronicity.