地震地质 ›› 2011, Vol. 33 ›› Issue (4): 777-788.DOI: 10.3969/j.issn.0253-4967.2011.04.004

• 活动构造 • 上一篇    下一篇

柯坪塔格山前层状地貌面与晚第四纪逆断层变形——以三岔口北西山前断错地貌为例

徐良鑫1, 冉勇康1, 刘华国1,2, 李安1   

  1. 1. 中国地震局地质研究所, 国家地震活断层研究中心, 北京 100029;
    2. 中国地震灾害防御中心, 北京 100029
  • 收稿日期:2011-09-01 修回日期:2011-11-08 出版日期:2011-12-30 发布日期:2012-01-12
  • 通讯作者: 冉勇康,研究员,E-mail: ykran@263.net
  • 作者简介:徐良鑫,男,1987年生,2009年毕业于中国地质大学(北京)宝石与材料工艺学专业,获学士学位。现为中国地震局地质研究所在读硕士研究生,主要从事活动构造方面的研究,电话010-62009140,E-mail: s0mile0@163.com。
  • 基金资助:

    国家自然科学基金(40872130)与财政部重大专项"我国地震重点监测防御区活动断层地震危险性评价"共同资助。

DEFORMATION OF REVERSE FAULT AND LAYERED LANDFORM IN PIEDMONT OF KALPINTAG MOUNTAINS DURING THE LATE QUATERNARY:EXAMPLE FROM THE FAULTED LANDFORM OF NORTHWESTERN SANCHAKOU

XU Liang-xin1, RAN Yong-kang1, LIU Hua-guo1,2, LI An1   

  1. 1. National Center for Active Fault Studies, Institute of Geology, China Earthquake Administration, Beijing 100029, China;
    2. China Earthquake Disaster Prevention Center, Beijing 100029, China
  • Received:2011-09-01 Revised:2011-11-08 Online:2011-12-30 Published:2012-01-12

摘要:

柯坪塔格山前三岔口北西发育了5级不同期次的冲洪积扇面,其中较年轻的3期完整地保留了断裂最新活动形成的陡坎。依据断错地貌面上砾石混合样品的10Be暴露年龄及差分GPS地形实测结果,计算出(20.22±1.91)ka以来T1、T2、T3级冲洪积扇上记录的断裂垂直滑动速率分别为(0.16±0.02)、(0.17±0.02)和(0.15±0.02)mm/a。T4、T5级地貌面的抬升速率为(0.51±0.05)、(0.58±0.05)mm/a,稍大于T1、T2、T3冲洪积扇面的结果。 柯坪塔格断裂在三岔口处出露的断层倾角为20°~40°,据此计算得到(20.22±1.91)ka以来柯坪塔格的水平缩短速率为0.19~0.58mm/a。

关键词: 柯坪塔格断裂, 断错地貌, 10Be暴露年代, 滑动速率

Abstract:

There are five different levels of alluvial fans developed at Sanchakou in the south edge of the Kalpintag Mountains.Kalpintag Fault has faulted three younger alluvial fans on which fault scarps caused by the latest fault activities are perfectly retained.To estimate the vertical slip magnitude and rates of the Kalpintag Fault during the late Quaternary,we investigated the latest evidences from the topographic and geomorphic survey of the fault scarps on the fans using differential GPS and the exposure 10Be age of amalgamated samples on the surface of abandoned fans.We estimated the cosmogenic nuclide contents accumulated during the post-depositional processes in the amalgamated samples on the fans collected from nearby active gullies.The vertical displacements of fault scarps we measured on the T1,T2 and T3 alluvial fans are 0.6±0.05,1.3±0.05 and 3.0±0.05m,respectively.Based on the 10Be exposure age of each alluvial fan,we calculated the vertical slip rate on T1,T2,T3 alluvial fans to be 0.15±0.02,0.16±0.02 and 0.15±0.02mm/a since(20.22±1.91)ka BP,with a corresponding crustal shortening rate of the Kalpintag Fault to be 0.18~0.44mm / a.The uplift rate since the formation of the T4 and T5 alluvial fans is 0.51±0.05 and 0.58±0.05mm/a,respectively,which is slightly bigger than that of T1,T2 and T3 alluvial fans.

Key words: Kalpintag Fault, layered landform, 10Be exposure age, slip rate

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