Thick Miocene eolian deposits on the Huajialing Mountains:The geomorphic evolution of the western Loess Plateau  

作　　者：ZHAN Tao GUO ZhengTang WU HaiBin GE JunYi ZHOU Xin WU ChunLin ZENG FangMing 

机构地区：[1]Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China [2]Graduate University of Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Science China Earth Sciences》2011年第2期241-248,共8页中国科学（地球科学英文版）

基　　金：supported by National Natural Science Foundation of China (Grant No. 40730104);Chinese Academy of Sciences (Grant Nos. KZCX2-YW-Q1-15 and KZCX2-YW-117)

摘　　要：The geomorphic evolution of northwestern China during the Cenozoic has been a subject of much geological interest because of its link with the uplift of the Himalayan-Tibetan complex.Much information about these changes is recoverable from the sedimentary sequences of the region.We report here on the thick eolian deposits mantling the Huajialing Mountains,a relatively flat mountain range in the western Loess Plateau.Correlation of magnetic susceptibility stratigraphy with the QA-I Miocene eolian sequence dates a 134.7 m section(NL-VII) for the interval from 18.7 to 11.8 Ma,as confirmed by micro-mammalian fossils.These eolian deposits demonstrate a much wider distribution of the Miocene eolian deposits,and also indicate that the topography contrasts in the western Loess Plateau,including the uplifts of the Huajialing Mountains and the bedrock highlands in the Qinan region,were formed by the early Miocene.The near-continuous Miocene eolian sequence from 18.7 to 11.8 Ma indicates that the substratum of Huajialing had not experienced any intense tectonic changes during this time interval,which suggests further,the relative tectonic stability of the nearby Tibetan Plateau.The geomorphic evolution of northwestern China during the Cenozoic has been a subject of much geological interest because of its link with the uplift of the Himalayan-Tibetan complex. Much information about these changes is recoverable from the sedimentary sequences of the region. We report here on the thick eolian deposits mantling the Huajialing Mountains, a relatively flat mountain range in the western Loess Plateau. Correlation of magnetic susceptibility stratigraphy with the QA-I Miocene eolian sequence dates a 134.7 m section （NL-VII） for the interval from 18.7 to 11.8 Ma, as confirmed by micromammalian fossils. These eolian deposits demonstrate a much wider distribution of the Miocene eolian deposits, and also indicate that the topography contrasts in the western Loess Plateau, including the uplifts of the Huajialing Mountains and the bedrock highlands in the Qinan region, were formed by the early Miocene. The near-continuous Miocene eolian sequence from 18.7 to 11.8 Ma indicates that the substratum of Huajialing had not experienced any intense tectonic changes during this time interval, which suggests further, the relative tectonic stability of the nearby Tibetan Plateau.

关 键 词：MIOCENE eolian deposits Huajialing Tibetan Plateau Cenozoic geomorphic evolution 

分 类 号：P736.22[天文地球—海洋地质] S157[天文地球—海洋科学]