地震地质 ›› 2017, Vol. 39 ›› Issue (5): 871-888.DOI: 10.3969/j.issn.0253-4967.2017.05.001

• 研究论文 • 上一篇    下一篇

榆木山北缘断裂现今构造活动特征及其对青藏高原北东扩展的构造地貌响应

陈干1, 郑文俊2, 王旭龙3, 张培震1,2, 熊建国2, 俞晶星1,4, 刘兴旺5, 毕海芸1, 刘金瑞1, 艾明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;
    3 中国科学院地球环境研究所, 西安 710075;
    4 牛津大学地球科学系, 英国牛津 OX13AN;
    5 中国地震局兰州地震研究所, 兰州 730000
  • 收稿日期:2017-03-23 修回日期:2017-06-18 出版日期:2017-10-20 发布日期:2017-11-22
  • 通讯作者: 郑文俊,男,教授,E-mail:zhengwenjun@mail.sysu.edu.cn
  • 作者简介:陈干,男,1993年生,2015年于合肥工业大学获资源勘查工程专业学士学位,在读硕士研究生,主要从事活动构造方面的研究工作,E-mail:chengan_93@126.com。
  • 基金资助:
    国家自然科学基金(41590861,41372220,41172194)与公益性行业科研专项经费项目(201408023)共同资助

PRESENT KINEMATICS CHARACTERISTICS OF THE NORTHERN YUMUSHAN ACTIVE FAULT AND ITS RESPONSE TO THE NORTHEASTWARD GROWTH OF THE TIBETAN PLATEAU

CHEN Gan1, ZHENG Wen-jun2, WANG Xu-long3, ZHANG Pei-zhen1,2, XIONG Jian-guo2, YU Jin-xing1,4, LIU Xing-wang5, BI Hai-yun1, LIU Jin-rui1, AI Ming1   

  1. 1 Institute of Geology, China Earthquake Administration, State Key Laboratory of Earthquake Dynamics, Beijing 100029, China;
    2 Guangdong Key Lab of Geodynamics and Geohazards, School of Earth Sciences and Engineering, Sun Yat-sen University, Guangzhou 510275, China;
    3 Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China;
    4 University of Oxford, Earth Science, England Oxford OX13AN;
    5 Lanzhou Institute of Seismology, China Earthquake Administration, Lanzhou 730000, China
  • Received:2017-03-23 Revised:2017-06-18 Online:2017-10-20 Published:2017-11-22

摘要: 榆木山北缘断裂位于祁连山逆冲断裂带中部,是榆木山隆起与河西走廊之间的分界断裂。探究榆木山北缘断裂的构造活动,有助于进一步了解祁连山向N的扩展过程以及青藏高原向NE方向推挤的机制。文中主要从断层滑动速率、古地震活动习性和构造变形3个方面总结了榆木山地区近20多年以来的研究成果。通过遥感影像解译、野外地质调查、断错位移测量及地貌面年龄测定等方法和手段,估算了榆木山北缘断裂典型位错点的逆冲滑动速率为(0.55±0.15) mm/a;左旋滑动速率为(0.95±0.11) mm/a。认为前人提出的"骆驼城陡坎"并非断层活动的产物,而是古代引水工程或水利灌溉工程的遗迹,也就是说它不是公元180年表氏地震的地表破裂。通过DEM剖面所反映的山体形态,结合断裂各项特征,认为榆木山隆起是祁连山向N推挤的结果,断裂活动目前仍集中在榆木山北侧,山体的形态受断层扩展控制,山脉的扩展是1个垂向和侧向的过程,晚新生代以来榆木山持续隆升。

关键词: 断层滑动速率, 公元180年表氏地震, 榆木山北缘断裂, 高原扩展, 青藏高原东北缘

Abstract: Qilian Shan and Hexi Corridor, located in the north of Tibetan plateau, are the margin of Tibetan plateau's tectonic deformation and pushing. Its internal deformations and activities can greatly conserve the extension process and characteristics of the Plateau. The research of Qilian Shan and Hexi Corridor consequentially plays a significant role in understanding tectonic deformation mechanism of Tibetan plateau. The northern Yumushan Fault, located in the middle of the northern Qilian Shan thrust belt, is a significant component of Qilian Shan thrust belt which divides Yumushan and intramontane basins in Hexi Corridor. Carrying out the research of Yumushan Fault will help explain the kinematics characteristics of the northern Yumushan active fault and its response to the northeastward growth of the Tibetan plateau.Because of limited technology conditions of the time, different research emphases and some other reasons, previous research results differ dramatically. This paper summarizes the last 20 years researches from the perspectives of fault slip rates, paleao-earthquake characteristics and tectonic deformation. Using aerial-photo morphological analysis, field investigation, optical simulated luminescence(OSL)dating of alluvial surfaces and topographic profiles, we calculate the vertical slip rate and strike-slip rate at the typical site in the northern Yumushan Fault, which is(0.55±0.15)mm/a and(0.95±0.11), respectively. On the controversial problems, namely "the Luotuo(Camel)city scarp" and the 180 A.D. Biaoshi earthquake, we use aerial-photo analysis, particular field investigation and typical profile dating. We concluded that "Luotuo city scarp" is the ruin of ancient diversion works rather than the fault scarp of the 180 A.D. Biaoshi earthquake. Combining the topographic profiles of the mountain range with fault characteristics, we believe Yumu Shan is a part of Qilian Shan. The uplift of Yumu Shan is the result of Qilian Shan and Yumu Shan itself pushing northwards. Topographic profile along the crest of the Yumu Shan illustrates the decrease from its center to the tips, which is similar to the vertical slip rates and the height of fault scarp. These show that Yumu Shan is controlled by fault extension and grows laterally and vertically. At present, fault activities are still concentrated near the north foot of Yumu Shan, and the mountain ranges continue to rise since late Cenozoic.

Key words: fault slip rates, 180 A.D. Biaoshi earthquake, Plateau growth, the northern Yumushan active fault, the northeast margin of Tibetan plateau

中图分类号: