文献类型：期刊文献

中文题名：库姆塔格沙漠地表物质组成、来源和风化过程

英文题名：Composition,Origin and Weathering Process of Surface Sediment in Kumtagh Desert,Northwest China

作者：徐志伟[1] 鹿化煜[1] 赵存法[1] 王先彦[1] 苏志珠[2] 王振亭[3] 刘宏宜[4] 王立新[1] 卢琦[2]

第一作者：徐志伟

机构：[1]南京大学地理与海洋科学学院;[2]中国林业科学研究院荒漠化研究所;[3]兰州大学资源环境学院;[4]中国气象局兰州干旱气象研究所

年份：2010

期号：1

起止页码：53-64

中文期刊名：地理学报

外文期刊名：Acta Geographica Sinica

收录：CSTPCD;;Scopus;北大核心:【北大核心2008】；CSCD:【CSCD2011_2012】；PubMed;

基金：国家科技基础性工作专项(2006FY110800);国家大学生创新训练计划项目(081028413);国家自然科学基金项目(40930103)联合资助~~

语种：中文

中文关键词：矿物;地球化学元素;物源;风化过程;库姆塔格沙漠

外文关键词：minerals; geochemical elements; sediments provenance; weathering process; Kumtagh Desert

分类号：P941.73;Q938.1

摘要：通过对库姆塔格沙漠地表沉积物样品进行重矿物和主量元素分析,获得了其矿物和元素组成特征:矿物种类多,绿帘石和角闪石含量为主;化学组成上以Si、Al为主,和上陆壳平均化学组成相比,除Si、Ca外都有一定的亏损,Fe、Mg、Ca、P、Ti、Mn等元素的变异系数较高。库姆塔格沙漠地表沙物质组成特征与阿尔金山北麓出露的岩石和冲、洪积扇物质组成基本一致,与塔克拉玛干沙漠也有很大的共性,反映了库姆塔格沙漠地表沙物质主要来源于阿尔金山。沙漠北区强烈的东北风将阿奇克谷地和疏勒河下游的河湖相沉积物搬运至沙漠腹地,构成另一个重要的沙物质来源。A-CN-K图解揭示了库姆塔格沙漠地表物质化学风化程度很低,处于较弱的去Na、Ca阶段,其他元素未发生明显的化学风化或迁移;A-CNK-FM图解表明,库姆塔格沙漠地表物质在搬运、沉积过程中Fe、Mg等元素发生显著分异,其原因主要是铁镁质矿物由于磨损、分选作用遭破碎和风化,使粒度较粗的沙漠沙Fe、Mg等元素相对亏损。
The Kumtagh Desert is one of the eight biggest deserts in China. In this study, 33 representative surface sediment samples were collected from Kumtagh Desert and analyzed in the laboratory to obtain composition of heavy mineral and content of geochemical elements. Results show that there are various kinds of heavy minerals in these samples, with large content of epidote and hornblende. Si and A1 take up a large part of chemical composition. Compared with the average composition of geochemical elements of the upper continental crust （UCC）, all elements except Si and Ca are depleted to a certain degree; Fe, Mg, Ca, P, Ti and Mn have high coefficients in their contents. Mineral composition of the samples of the Kumtagh Desert has a similarity with that of rocks of Altyn Tagh, surface sediments of the alluvial/fluvial fans of the Aityn Tagh and that of the Taklamakan Desert, indicating that one major source of the Kumtagh Desert sediments is located in Altyn Tagh. Alluvial deposits and lake sediments in Aqik valley and lower reaches of the Sule River are prone to be eroded and transported by the strong northeasterly wind to the Kumtagh Desert, as a result these places form another source of surface deposits of the Kumtagh Desert. A-CN-K ternary diagram shows that a weak chemical weathering by loss of Na and K occurred in these sediments, while other geochemical elements was in a less weathering or leaching process. A-CNK-FM ternary diagram suggests that Fe and Mg have distinct chemical differentiation. Physical weathering process makes it easy for mafic minerals to be eroded and enriched in fine particles, thus coarse desert sand particles can be relatively depleted in Fe and Mg. Mineral and geochemical composition of sediments in arid regions with less chemical weathering are mostly effected by physical processes.