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中国沙漠 ›› 2021, Vol. 41 ›› Issue (3): 127-136.DOI: 10.7522/j.issn.1000-694X.2021.00034

• • 上一篇    

柴达木盆地西北部长垄状雅丹沉积物地球化学元素组成及指示意义

郜学敏1(), 屈欣2, 王萌2, 张思悦2, 张姚姚2, 李继彦2()   

  1. 1.晋中学院 旅游管理系,山西 晋中 030619
    2.太原师范学院 地理科学学院,山西 晋中 030619
  • 收稿日期:2021-02-08 修回日期:2021-03-22 出版日期:2021-05-26 发布日期:2021-05-26
  • 通讯作者: 李继彦
  • 作者简介:李继彦(E-mail: jyli@tynu.edu.cn
    郜学敏(1987—),女,山西陵川人,博士,讲师,主要从事风沙地貌、旅游地理研究。E-mail: waipoqiaoqt@163.com
  • 基金资助:
    国家自然科学基金项目(41601005)

Composition of geochemical elements and its implications for long-ridge yardang in the northwestern Qaidam Basin China

Xuemin Gao1(), Xin Qu2, Meng Wang2, Siyue Zhang2, Yaoyao Zhang2, Jiyan Li2()   

  1. 1.Department of Tourism Management,Jinzhong University,Jinzhong 030619,Shanxi,China
    2.School of Geography Science,Taiyuan Normal University,Jinzhong 030619,Shanxi,China
  • Received:2021-02-08 Revised:2021-03-22 Online:2021-05-26 Published:2021-05-26
  • Contact: Jiyan Li

摘要:

雅丹沉积物蕴含丰富的区域环境变化和物源演变信息。以柴达木盆地西北部的长垄状雅丹为研究对象,通过对地球化学元素的研究,探讨沉积物的化学风化特征及其对物质输移的指示意义。结果表明:(1)雅丹沉积物的常量元素以SiO2、CaO、Al2O3、MgO和Na2O为主,微量元素Cl、Sr、Ba和Zr含量较高。相较于上陆壳平均化学元素组成,雅丹沉积物常量元素CaO和MgO富集程度较高,微量元素中Cl和As富集程度较高。(2)雅丹沉积物的CIA值平均为39.03,且在A-CN-K三角图上准平行于A-CN连线,主体在斜长石与钾长石连线的下方,因此雅丹沉积物的化学风化程度较低,处于初期的脱Na、Ca阶段。(3)特征元素比值表明雅丹体内赋存的大量细颗粒物质为廊道流沙的源区。细颗粒物质经过外营力的风化、剥蚀等过程而出露,在雅丹廊道内堆积并向下风向输移,遇阻堆积而形成沙丘。雅丹是否为下风向黄土的物源区,尚需进一步验证。

关键词: 雅丹, 化学风化, 地球化学元素, 柴达木盆地

Abstract:

Yardangs are enigmatic landforms, whose formation and evolution processes are still not fully understood. Yardang strata bear abundant information on the change of regional environment and provenance for the development of yardangs. This paper selected the long-ridge yardang in the northwestern Qaidam Basin as research object, and investigated the chemical weathering of yardang strata and their implications for the transportation of sand-sized grains in the Qaidam Basin by analyzing the composition of geochemical elements. The results indicated that the major elements were dominated by SiO2, CaO, Al2O3, MgO and Na2O, while the contents of Cl, Sr, Ba and Zr were in dominant for the trace elements in yardang sediments. Compared to the average content of chemical elements for the upper continental crust, the enrichment of major elements such as CaO and MgO, and trace elements such as Cl and As was in a high degree. The mean value of CIA was 39.03 for long-ridge yardang sediments, and they quasi were parallel to the A-CN line and behind the connecting line between plagioclase and potassium feldspar in the A-CN-K tertiary diagram, which indicated that the chemical weathering of long-ridge yardang sediments in the Qaidam Basin was in the early stage of losing Na and Ca. Ratios of characteristic elements demonstrated that the abundant fine-grained particles in the yardang bodies were the source of drift sands in the yardang corridors. These drift sands were exposed by the weathering and erosion of exogenic agents and accumulated in the yardang corridors. And they can developed into sand dunes when they blocked by obstacles during their transportation in the downwind direction. However, as to whether the yardangs were the source of downwind loess still need further investigation.

Key words: yardang, chemical weathering, geochemical element, Qaidam Basin

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