SEISMOLOGY AND GEOLOGY ›› 2021, Vol. 43 ›› Issue (3): 521-539.DOI: 10.3969/j.issn.0253-4967.2021.03.004

• Research paper • Previous Articles     Next Articles

TECTONIC GEOMORPHIC FEATURES AND GEOLOGICAL SIGNIFICANCE OF THE SHIDIQUAN ANTICLINE IN THE NORTHERN MARGIN OF THE QAIDAM BASIN

DONG Jin-yuan1), LI Chuan-you1), ZHENG Wen-jun2), LI Tao1), LI Xin-nan1), REN Guang-xue1), LUO Quan-xing1)   

  1. 1)State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China;
    2)Guangdong Provincial Key Laboratory of Geodynamics and Geohazards, School of Earth Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
  • Received:2020-04-27 Revised:2020-07-20 Online:2021-06-20 Published:2021-07-20

柴达木盆地北缘石底泉背斜构造地貌特征及地质意义

董金元1), 李传友1),*, 郑文俊2), 李涛1), 李新男1), 任光雪1), 罗全星1)   

  1. 1)中国地震局地质研究所, 地震动力学国家重点实验室, 北京 100029;
    2)中山大学地球科学与工程学院, 广东省地球动力作用与地质灾害重点实验室, 广州 510275
  • 通讯作者: *李传友, 男, 1971年生, 研究员, 现主要研究方向为活动构造, E-mail: chuanyou@ies.ac.cn。
  • 作者简介:董金元, 男, 1988年生, 现为中国地震局地质研究所构造地质学在读博士研究生, 研究方向为活动构造, E-mail: dongjinyuan@163.com。
  • 基金资助:
    第2次青藏高原科学考察研究(2019QZKK0901)和国家自然科学基金(41590861)共同资助

Abstract: In the process of intense compression and shortening of the orogenic belt, a series of thrust faults and folds related to reverse faults developed in the piedmont. Determining the kinematic characteristics of these reverse faults and folds is of great significance for understanding the deformation mode of the orogenic belt. The Qilian Shan is located on the northeastern margin of the Tibetan plateau and is the front edge of the plateau expansion. The area has undergone strong tectonic activity since the Late Quaternary, with developed active structures and frequent earthquakes. There are a series of piedmont thrust faults and thrust related folds in the northern and southern margins of Qilian Shan. Compared with a large number of research results of active folds in Tian Shan area, the study of active folds in Qilian Shan is relatively weak. In the northern margin of the Qilian Shan, in addition to the study of individual active folds, most previous studies focused on the thrust faults in the northern margin of the Qilian Shan and the Hexi Corridor, and obtained the active characteristics of these faults. In the southern margin of Qilian Shan, that is, the northern margin of the Qaidam Basin, some studies have been carried out on paleoearthquakes and slip rate of the fault in the southern margin of Zongwulong Shan. However, the study on the late Quaternary folds in this area is relatively weak and there are only some sporadic works.
Shidiquan anticline is located in the intermountain basin surrounded by Zongwulong Shan and Hongshan in the northern margin of Qaidam Basin. It forms the first row fold structure in front of Zongwulong Shan with Huaitoutala and Delingha anticline. Constraining the tectonic geomorphic features of the Shidiquan anticline is of great significance for studying the crustal shortening in the northern margin of the Qaidam Basin and the expansion of the Qilian Shan to the Qaidam Basin. In this paper, the tectonic and geomorphic characteristics of Shidiquan anticline are obtained by means of geological mapping, high-precision differential GPS topographic profile survey, geological profile survey and cosmogenic nuclide dating. Field investigation shows that Shidiquan anticline is an asymmetric fold with steep south limb and gentle north limb, and is controlled by a blind reverse fault dipping northward. The age of the alluvial fan3 obtained from cosmogenic nuclide dating is(158.32±15.54)ka. This age coincides with the Gonghe Movement, indicating that the formation of Shidiquan anticline responds to the Gonghe Movement in the northeast margin of Tibetan plateau. The uplift rate of Shidiquan anticline since 158ka is(0.06±0.01)mm/a, and the shortening rate is(0.05±0.01)mm/a. The folding effect of Shidiquan anticline indicates that the folding of the intermountain basin in the northern margin of the Qaidam Basin, similar to the thrust shortening of the piedmont fault, plays an important role in regulating the shortening of the foreland crust.

Key words: Shidiquan anticline, northern Qaidam Basin, Qilian Shan, fold deformation, Gonghe Movement

摘要: 石底泉背斜位于柴达木盆地北缘宗务隆山与红山围限的山间盆地内, 与怀头他拉背斜、 德令哈背斜构成宗务隆山山前的第1排褶皱构造, 限定石底泉背斜的构造地貌特征对研究柴达木盆地北缘构造变形、 地壳缩短和青藏高原的向N扩展具有重要意义。 文中通过地质地貌填图、 高精度差分GPS地形剖面测量、 地质剖面测绘和宇宙成因核素定年等方法, 获得了石底泉背斜的构造地貌特征。 基于宇宙成因核素定年获得构成褶皱主体的Fan3洪积扇的年龄为(158.32±15.54)ka, 该年龄与共和运动同期, 表明石底泉背斜的形成响应了青藏高原东北缘的共和运动。 综合洪积扇变形量和废弃年代, 获得石底泉背斜自158ka BP以来的隆升速率为(0.06±0.01)mm/a, 缩短速率为(0.05±0.01)mm/a。 石底泉背斜的褶皱作用表明, 在柴达木盆地北缘, 山间盆地的褶皱作用与山前逆断裂的逆冲缩短相同, 均对造山带前陆的地壳缩短具有重要的调节作用。

关键词: 石底泉背斜, 柴达木盆地北缘, 祁连山, 褶皱变形, 共和运动

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