SEISMOLOGY AND GEOLOGY ›› 2018, Vol. 40 ›› Issue (1): 71-86.DOI: 10.3969/j.issn.0253-4967.2018.01.006

Previous Articles     Next Articles

LATE QUATERNARY CRUSTAL SHORTENING RATE OF THE BEILUNTAI FAULT IN SOUTHERN TIAN SHAN, XINJIANG

YAO Yuan1, SONG He-ping1, CHEN Jian-bo1, LI Shuai1, JIA Hai-liang2   

  1. 1. Earthquake Agency of Xinjiang Uygur Autonomous Region, Urumqi 830011, China;
    2. School of Architecture and Civil Engineering, Xi'an University of Science and Technology, Xi'an 710000, China
  • Received:2017-11-15 Revised:2017-12-12 Online:2018-02-20 Published:2018-04-13

新疆天山南部北轮台断裂带晚第四纪活动速率

姚远1, 宋和平1, 陈建波1, 李帅1, 贾海梁2   

  1. 1. 新疆维吾尔自治区地震局, 乌鲁木齐 830011;
    2. 西安科技大学建筑与土木工程学院, 西安 710000
  • 作者简介:姚远,男,1988年生,2012年于中国地质大学(武汉)工程学院获得硕士学位,工程师,主要从事第四纪地质、构造地质方面的研究工作,电话:0991-3853817,E-mail:yy8096658@126.com。
  • 基金资助:
    地震科技星火计划(XH17042Y)、北轮台断裂东段1:5万地质填图项目与国家自然科学基金(41702334)共同资助

Abstract: The Beiluntai Fault is a Holocene active fault. It is the boundary between southern Tian Shan and Tarim Basin. Since the late Quaternary, steady activities of the Beiluntai fault have resulted in offsets, folds, and uplift of pluvial terraces. We used the high-resolution RTK topographic surveys to reveal that the fault scarp morphology on the Akeaiken(Ak) segment and Zhuanchang(Zc) segment of the Beiluntai fault. We found that the crustal shortening of Ak and Zc segments are dominated by thrusting and folding-uplift, respectively. We employed th optically stimulated luminescence(OSL) dating method to develop a new chronology for the different pluvial terraces, indicating that they formed at 49.14~58.51, 27±3, 13.72~14.64, 7.13±0.88, (3.32±0.43) ka, respectively. These data permitted to estimate the crustal shortening rate(about 2.4mm/a) remains largely constant on the Ak segment, while the crustal shortening rate of Zc segment was 1.43~1.81mm/a since the Fan4 pluvial terraces was abandoned. Compared with the Ak segment, the crustal shortening rate of the Zc segment declined obviously. This shows that the NS-trending crustal shortening rate of the Beituntai fault decreased gradually from west to east. A comprehensive comparison of the reverse fault-fold belt system in the front of southern Tian Shan also indicates that the crustal shortening rate drops from west to east.

Key words: Tian Shan, Beiluntai fault, thrust, fold, late Quaternary

摘要: 北轮台断裂是1条全新世活动断裂,为南天山与塔里木盆地的分界断裂。晚第四纪以来,北轮台断裂的持续活动使得多期洪积地貌面发生了断错变形与褶皱隆升。利用高精度差分GPS,对北轮台断裂阿克艾肯段和砖厂段内的多期地貌面的断层陡坎形态进行了测量。通过大比例尺活动断层填图发现,阿克艾肯段以逆冲作用为主,而砖厂段则是以褶皱隆升为主。利用光释光测年方法,分别得到了不同期次地貌面(Fan4,Fan3b,Fan3c和Fan2)的年龄,发现自Fan4地貌面形成以来,阿克艾肯段的地壳缩短速率(约2.4mm/a)基本保持恒定;同时,晚第四纪以来砖厂段的SN向地壳缩短速率为1.43~1.81mm/a,较阿克艾肯段有明显下降,推测北轮台断裂带的SN向地壳缩短速率由西向东递减。综合对比南天山山前的逆断裂-褶皱带体系,同样反映出地壳缩短速率由西向东递减的特征。

关键词: 天山, 北轮台断裂带, 逆冲变形, 褶皱变形, 晚第四纪

CLC Number: