四川金川黄土地层  

The Jinchuan Loess Stratigraphy in Western Sichuan Plateau

作　　者：王书兵[1,2] 蒋复初[1,2] 田国强[1] 傅建利[1] 刘萪[1] 赵志中[1] 

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]中国科学院黄土和第四纪地质国家重点实验室

出　　处：《地球学报》2005年第4期355-358,共4页Acta Geoscientica Sinica

基　　金：中国科学院知识创新工程项目(编号:KZCX2-108);国土资源部基础研究项目(批准号:20010202;991005);中国地质调查局项目(批准号:200312300034);国家自然科学基金项目(批准号:40302025;40302036)共同资助。

摘　　要：马厂剖面中黄土-古土壤序列共厚15.5m,根据岩性、磁性地层特征、磁化率、CaCO3含量和光释光测年结果,将金川黄土划分为冰后期S0古土壤,末次冰期L1黄土,末次间冰期S1古土壤、倒数第二冰期L2黄土和倒数第二间冰期S2古土壤等5个地层单位;其中,S1复合型古土壤又可细分为S1LL1、S1LL2黄土和S1SS1、S1SS2和S1SS3古土壤等5个次级地层单位。金川黄土沉积始于中更新世晚期,其底界的年龄大致为200kaBP,其磁化率变化反映了最近200ka来的高原季风演化和气候环境变迁,5个磁化率高值段指示了5个夏季风环流增强的时段,4个磁化率低值段则代表了4次夏季风减弱的时期。There exists widespread eolian loess in western Sichuan plateau. A preliminary study of the loess strata in Jincuan area was carried out, in which Macang profile was measured. According to characteristics of lithology, magnetostratigraphy, susceptibility, CaCO3 content and thermoluminescent dating, the loess sequence can be divided into five stratigraphic units, namely paleosol So, loess L1, paleosol S1 , loess L2 and paleosol S2 which were formed in the postglacial period, last glaciation, last interglaciation, last but one glaciation, and last but one interglaciation respectively. Among them, the compound paleosol S1 can be subdivided into five secondary stratigraphic units, i.e. , loess S1 LL1, S1 LL2, paleosol S1SS1, S1SS2 and S1SS3. The deposition of the Jincuan loess began at the late Middle Pleistocene, about 200 ka B P. The evolution of plateau monsoon and the change of climate environment can be indicated by the susceptibility of the Jincuan loess strata in the last 200 ka. , in which five intensified sunmmr monsoon circulations are shown by higher values of susceptibility, and four weakened circulations are indicated by the lower values.

关 键 词：黄土 磁性地层 川西高原 金川 黄土地层 黄土-古土壤序列 CaCO3含量 末次间冰期 夏季风环流 四川 

分 类 号：P642.131[天文地球—工程地质学] TU457[天文地球—地质矿产勘探]