摘要
对柴达木盆地不同地貌地表沉积物样品中的矿物构成进行分析,结果表明,柴达木盆地沙漠地表沉积物中轻矿物平均质量百分含量为89.45%,变化在32.57%～98.43%,且不同地貌表层沉积物的轻矿物组成存在较大差异;轻矿物成分成熟度指数Q/TF的平均值为1.65,变化范围是1.43～1.82,沙丘沉积物的轻矿物成分成熟度指数高于其他地貌类型。柴达木盆地沙漠地表沉积物中重矿物平均重量百分含量为0.82%,变化在0.11%～4.24%,以不稳定矿物为主;重矿物特征指数中ATi指数平均值为68.82,GZi指数平均值为80.91,ZTR指数平均值为2.15。研究后认为,柴达木盆地沙漠中沙物质的来源途径为：①河流冲、洪积作用将高山剥蚀产物带入盆地腹地,后经风力吹蚀、分选形成沙漠;②察尔汗盐湖退化后的湖相沉积物提供了丰富的沙源,在西北风的强烈作用下“就地起沙”,沉积形成沙漠。
In the Qaidam Basin, there are some typical sand dunes, such as linear dune and barchans dune, which distribute to the similar physical environment. In this study, the representative surface sediment samples were collected from the Qaidam Basin Desert and analyzed in the laboratory to obtain mineral composition. The results show that： ①Light mineral dominate in content, with 89.45% on average and the different composi- tions are distributed in different landforms; the Q/TF ratio in light mineral, with 1. 65 on average, exists in the surface sediment and its value of sand dunes, however, is higher than other landfbrms include Yardman, historical sand dunes, diluvia fan etc. ②In these samples little heavy minerals exist, with average 0. 82%. The number of mineral species is various, however, unstable minerals account for a big proportion in heavy minerals ; the deposition environment of Qaidam Basin was indicated by the ATi ratio （ average 68.82） , GZi ratio （ average 80. 91 ） and ZTR ratio （ average 2. 15 ） in the heavy mineral. ③The origin of sand sediments is from two ways： one is that the weathered substance was transported from mountain to basin by fluvial and developed desert by wind erosion; the other is that the lake sediments, with the shrinking salt lake, become the local origin of sand particle and the landforms were developed by the NW direction of wind deposition.
出处
《西北大学学报（自然科学版）》
CAS
CSCD
北大核心
2015年第1期90-96,共7页
Journal of Northwest University（Natural Science Edition）
基金
教育部"长江学者"特聘教授基金资助项目(801813)
国家重大科学研究计划基金资助项目(2013CB956000)
国家自然科学基金资助项目(41130533
41171010)
关键词
矿物成分
沙丘
柴达木盆地
mineral composition
sand dunes
Qaidam Basin
