新疆伊犁黄土磁化率增强机制差异性分析  

Differences in Magnetic Susceptibility Enhancement in Ili Loess,Xinjiang

作　　者：李传想[1,2] 宋友桂[1] 

机构地区：[1]中国科学院地球环境研究研究所,黄土与第四纪地质国家重点实验室,陕西西安710075 [2]中国科学院研究生院,北京100049

出　　处：《地球学报》2011年第1期80-86,共7页Acta Geoscientica Sinica

基　　金：国家重点基础研究规划项目(编号:2010CB833406);国家自然科学基金(编号:40972230,40772116);黄土与第四纪地质国家重点实验室自主部署课题(编号:LQ0701)联合资助

摘　　要：本文对处于西风区的新疆伊犁昭苏黄土剖面进行了磁化率和粒度分析,初步探讨了伊犁黄土磁化率增强机制的差异性。研究表明,伊犁黄土虽然粘土含量较黄土高原黄土高,但细粒组分对磁化率的贡献非常有限,粗颗粒组分对磁化率贡献较大,说明磁性载体主要存于粗颗粒组分中。同时研究发现地形、沉积环境、源区矿物组分和气候等多种因素对磁化率产生不同程度的影响。伊犁黄土磁化率成因机制既具有阿拉斯加风速论模式的特点又叠加了黄土高原成壤作用的模式,即使在同一剖面的不同时段两种模式对磁化率增强的贡献也不同,伊犁黄土磁化率增强机制存在着时空差异性。In this paper,the authors have analyzed loess magnetic susceptibility and grain sizes along the Zhaosu section in Ili basin of Xinjiang dominated by the westerlies,and discussed the differences in the enhancement mechanism of magnetic susceptibility of the Ili loess.Studies show that although the content of fine clay is higher in the Ili loess than that in the loess plateau,the contribution of fine components to the loess magnetic susceptibility is very limited,suggesting that the magnetic carriers in the study area exist mainly in the coarse components.The authors hold that the mechanism of susceptibility formation in the Ili loess can be interpreted as either Alaska wind model or pedogenesis model of the Chinese Loess Plateau.However,the two models make different contributions to the loess magnetic susceptibility in different regions of the Ili basin,and even make different contributions to the enhancement of magnetic susceptibility in different periods of the same section,i.e.,the enhancement mechanism of magnetic susceptibility in the Ili loess has spatial-temporal differences due to the influence of various factors,such as climate,topography,source mineral components and sedimentary environment.

关 键 词：伊犁黄土 磁化率 粒度 中亚 增强机制 

分 类 号：P318.21[天文地球—固体地球物理学] P318.41[天文地球—地球物理学]