青藏高原东北缘柴达木盆地红沟剖面物源分析及其构造意义
作者:
作者单位:

作者简介:

通讯作者:

中图分类号:

基金项目:

本文为重点研发项目(2017YFC1500104);自然科学基金(41872204, 41590861, 41603054);地震动力学国家重点实验室基金 (LED2017A04)共同资助成果。


Provenance identification for the Honggou section of the Qaidam basin in the northeastern margin of the Tibetan Plateau and its tectonic significance
Author:
Affiliation:

Fund Project:

  • 摘要
  • |
  • 图/表
  • |
  • 访问统计
  • |
  • 参考文献
  • |
  • 相似文献
  • |
  • 引证文献
  • |
  • 资源附件
  • |
  • 文章评论
    摘要:

    青藏高原东北缘柴达木盆地红沟剖面发育巨厚的新生代沉积地层,通过分析其沉积物质来源,可以揭示柴达木盆地潜在物源区隆升、剥蚀历史,为高原东北缘新生代构造变形过程提供证据。本文以红沟剖面磁性地层年代框架为约束,对剖面晚渐新世上新世的碎屑砂岩样品进行了碎屑锆石物源示踪分析。研究结果表明,23. 7~12. 5 Ma样品的锆石UPb年龄主要分布在220~290 Ma,锆石 ε Hf( t )集中在-13. 53~9. 27,Hf同位素 t DM 范围524~1456 Ma;大于300 Ma 的锆石,ε Hf ( t )介于-31. 77~13. 44,其中76. 3%为负值,Hf同位素 t DM 介于484~3727 Ma。采集自12. 5~7. 6 Ma样品的锆石UPb年龄主要集中在400~500 Ma(峰值~440 Ma), ε Hf ( t )值(-27. 75 ~10. 75)的90% 为负值,Hf同位素 t DM 介于615~2115 Ma之间。6. 8~5. 5 Ma样品的锆石UPb年龄主要分布在400~500 Ma, ε Hf ( t )值(-26. 8~8. 97), t DM(Hf) 介于668~2093 Ma,但220~290 Ma的锆石显著增加,其 ε Hf ( t )值(-11. 86~9. 42),Hf一阶段模式年龄范围549~1399 Ma。碎屑锆石Hf同位素组成对比分析显示红沟剖面220~290 Ma的锆石与东昆仑山锆石Hf同位素特征相似,而400~500 Ma的锆石则与南祁连山锆石Hf同位素组成相似,揭示东昆仑山在>24 Ma开始抬升成为柴达木盆地的源区,~12 Ma南祁连山开始隆升,为柴达盆地提供碎屑物质,成为青藏高原东北缘的构造与地貌边界。

    Abstract:

    Located in the northeastern corner of the Tibetan Plateau, the Honggou section deposits comprise thick Cenozoic strata,the provenance analysis of which provides an exceptional opportunity to study the uplift and denudation history of the potential source regions for the Qaidam Basin and the deformational processes in the northeast Tibetan Plateau. Here, the detrital zircon U- Pb ages and Hfisotopic compositions are used to trace the source changes for the Late Oligocene- Pliocene strata based on the magnetostratigraphy of the Honggou section. Most of the U- Pb ages of the detrital zircon from 23. 7~12. 5 Ma are concentrated within the intervals of 220~290 Ma, the ε Hf( t ) is concentrated at -13. 53~9. 27, and the range of the t DM(Hf) is 524~1456 Ma. For zircons whose U- Th age are greater than 300 Ma, the ε Hf( t ) is between -31. 77 and 13. 44, of which 76. 3% is negative, and the Hf isotope t DM is between 484 and 3727 Ma. The zircon U- Pb ages of sandstone samples from 12. 5~7. 6 Ma are mainly concentrated at 400~500 Ma (peak ~ 440 Ma), 90% of the ε Hf( t ) value (-27. 75~10. 75) is negative, Hf isotope one- stage model age is between 615~2115 Ma. Sandstone samples of 6. 8~5. 5 Ma, zircon U- Pb age is mainly distributed at 400~500 Ma, the ε Hf( t ) value is ranging from -26. 8 to 8. 97, and the t DM is between 668~2093 Ma, but the zircon ages of 220~290 Ma increase significantly, having ε Hf( t ) values ranging from -11. 86 to 9. 42, Hf one- stage model age range is 549~1399 Ma. Comparing these with neighboring tectonic units, we found that Hf isotopic compositions of zircon whose populations are at 220~290 Ma have affinity with the East Kunlun Shan, while the Hf isotopic composition of 400~500 Ma zircon is similar to South Qilian Shan. These features reveal that the East Kunlun Shan began to deform and become the main source region of the Qaidam Basin at 24Ma. The southward expansion of the Qilian Shan is at ~12 Ma, providing detrital materials for the Qaidam Basin and becoming the tectonic and geomorphic margin along the Tibetan Plateau.

    参考文献
    相似文献
    引证文献
引用本文

刘康,王伟涛,赵旭东,庞建章,俞晶星.2020.青藏高原东北缘柴达木盆地红沟剖面物源分析及其构造意义[J].地质学报,94(3):716-728.
LIU Kang, WANG Weitao, ZHAO Xudong, PANG Jianzhang, YU Jingxing.2020. Provenance identification for the Honggou section of the Qaidam basin in the northeastern margin of the Tibetan Plateau and its tectonic significance[J]. Acta Geologica Sinica,94(3):716-728.

复制
分享
文章指标
  • 点击次数:
  • 下载次数:
  • HTML阅读次数:
  • 引用次数:
历史
  • 收稿日期:2019-10-31
  • 最后修改日期:2019-12-23
  • 录用日期:
  • 在线发布日期: 2020-02-21
  • 出版日期: