伊犁尼勒克黄土石英颗粒微形态特征及其成因与物源意义  

Micromorphological characters of quartz grain from Nilke loess-paleosol sequences and their implications of origin and provenance

作　　者：李越[1] 宋友桂[1] 赵井东[2] 

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710061 [2]中国科学院寒区旱区环境与工程研究所,兰州730000

出　　处：《地球环境学报》2016年第4期366-379,共14页Journal of Earth Environment

基　　金：国家自然科学基金项目(41572162;41172166);中国科学院地球环境研究所自主部署重点项目(ZZBS1301);中国科学院科技创新"交叉与合作团队"项目(中科院人字[2013]47号);中国科学院国际合作局对外合作重点项目(132B61KYS20160002)~~

摘　　要：石英颗粒表面微形态分析是判断沉积物成因和来源的重要方法之一。对伊犁盆地尼勒克黄土石英颗粒表面微形态特征进行了研究,并将其与冰川、河流、沙漠样品进行比较,结果表明尼勒克黄土石英颗粒磨圆较差,冰川和水流作用的微形态特征明显,系近源风力搬运沉积。通过对比分析讨论了石英粉砂的可能产生机制,认为流水和寒冻风化作用为伊犁黄土的形成提供了重要动力来源。尼勒克黄土的物质来源和匈牙利黄土类似,而与黄土高原黄土有较大差别,这主要表现在经受风力搬运-沉积的次数上或者风力搬运的距离上。该研究为解译伊犁地区黄土的古气候环境意义提供了重要基础。Background, aim, and scope Xinjiang is also one of the most significant loess regions in China with the exception of Chinese Loess Plateau, and the loess is mainly present in the northern piedmont of the Tianshan and Kunlun Mountains and Ili Basin. The loess deposits in Ili Basin unconformably cover the river terraces, the low uplands and the slopes of the Tianshan Mountains, and the researches on them have the merit of enabling reconstructions of past climate change in westerly dominant area of inland Asia. Although many predecessors have investigated the spatial distribution and studied the ages, pedostratigraphy, rock magnetism, elemental and mineral compositions and their implications for paleoclimate in details with respect to the Ili loess, there are many urgent questions that need to be solved： How were the materials of Ili loess generated？ Which geological process was experienced by the loess silt particles before they reached the sediment area？ And where is the provenance of Ili loess？ We have had no understanding of the answers by far, which hampers the interpretation of climate change. For this reason, this paper aims to solve the problems above mentioned with the micromorphological characters of quartz grains. In recent study, we compared the micromorphology of quartz grains from Nilka loess with those from glacial tills, riverbed deposits and desert sands to determine the mechanisms of loess-sized quartz silt production. These works will lay the foundation for the subsequent studies on the Ili loess. Materials and methods The 4 loess samples were collected from Nlika section located at the second-order terrace of Kashi River in the east of Ili Basin with the depths 1.50 m, 9.10 m, 11.06 m and 19.56 m, respectively. Glacial till was sampled from the terminus of Arqialeter Glacier located in catchment area of Xiate River; riverbed deposits were sampled from Kashi River and the sampling sites lay in the west of Nilka loess section; desert sands were sampled from Kyzylkum, Muyunkum and Saryeslk A

关 键 词：伊犁黄土 石英颗粒表面结构 成因与来源 

分 类 号：S152[农业科学—土壤学]