塔吉克斯坦黄土矿物与稀土元素组成特征  

Mineralogical and REE geochemical compositions of Tajikistan loess

作　　者：宋友桂[1] 李越[1,2] 陈秀玲[3] 李云[1] 

机构地区：[1]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安710075 [2]中国科学院大学,北京100049 [3]福建师范大学地理科学学院福建省湿润亚热带山地生态省部共建国家重点实验室培育基地,福州350007

出　　处：《地球环境学报》2014年第2期145-154,共10页Journal of Earth Environment

基　　金：国家自然科学基金项目(41172166);中国科学院自主布署项目(ZZBS1301);中国科学院科技创新"交叉与合作团队"项目

摘　　要：黄土矿物和地球化学组成是研究黄土来源和成因的重要手段。利用X射线衍射(XRD)和电感耦合等离子体质谱技术(ICP-MS)对亚洲内陆塔吉克斯坦共和国的黄土分别进行了矿物组成和稀土元素(REE)特征分析,并与黄土高原和新疆伊犁黄土进行了对比。研究结果表明:XRD鉴定出塔吉克斯坦黄土有10多种矿物,以石英为主,其次为长石、方解石,还有少量绿泥石、云母类、白云石等,偶见多种重矿物,其矿物组成与黄土高原和新疆伊犁黄土类似,但石英、方解石的含量较低,角闪石含量介于黄土高原与伊犁黄土之间,反映近源弱风化的环境。稀土元素总含量(∑REE)变化于130.61~205.62μg·g^(-1),平均值为158.81μg·g^(-1),明显低于黄土高原黄土和新疆黄土,但黄土与古土壤的REE特征参数及配分模式具有很好的相似性,说明两者具有类似的风成成因。塔吉克斯坦黄土不同时代的矿物成分和REE特征参数、配分模式与黄土高原、新疆黄土接近,显示出其经过搬运后的高度混合性特征,亦指示其为风成成因,而含量的细微差异则主要反映了区域地质背景和源区的不同。Mineralogical and geochemical compositions of loess are important characteristics which canbe used to track provenance and origin. With X-ray diffraction （XRD） and inductively coupled plasmamassspectrometer （ICP-MS）, mineralogical compositions and REE characteristics in Tajikistan （TJ）loess were carried out. Meanwhile, we compared them with CLP and Ili loess. The results indicate thatat least ten minerals in Tajikistan are identified through XRD, and in addition to quartz, the primarymineral composing Tajikistan loess, followed by feldspar and calcite, there are few chlorite, micas,dolomite, etc., and some kinds of heavy minerals found by accident. Although TJ, CLP and Ili loesshave the similar characteristics in mineralogical compositions, the contents of quartz and calcite arelower in TJ, with the content of hornblende between CLP loess and Ili loess, reflecting the weaklyweathering environment near provenance. The gross amount of rare earth elements （ΣREE） of Tajikistanloess varied in the range from 130.61 μg·g^-1 to 205.62 μg·g^-1 with an average value of 158.81 μg·g^-1,conspicuously less than those of CLP and Ili loess, whereas loess and paleosol in Tajikistan have quitesimilar REE character parameters as well as distribution patterns, indicating similarly eolian originsof both. Tajikistan loess of different ages have similar mineralogical compositions and REE characterparameters and distribution patterns of CLP and Ili loess, displaying the characteristics of high mixtureafter transportation, as well as the eolian origin of the Tajikistan loess. But the subtle difference of theirREE contents mainly reflects the discrepancy of regional geological background and provenance.

关 键 词：塔吉克斯坦 黄土 矿物 稀土元素 化学风化意义 

分 类 号：S151.9[农业科学—土壤学] P595[农业科学—农业基础科学]