地理学报 ›› 2012, Vol. 67 ›› Issue (5): 681-688.doi: 10.11821/xb201205010

• 第四纪研究 • 上一篇    下一篇

新疆独山子的冲沟发育与断层新活动

钱蟒, 李有利, 司苏沛, 吕胜华, 王怡然   

  1. 北京大学城市与环境学院地表过程重点实验室,北京100871
  • 收稿日期:2011-12-07 修回日期:2012-02-19 出版日期:2012-05-20 发布日期:2012-05-20
  • 通讯作者: 李有利(1965-), 男, 教授, 主要从事构造地貌学与环境演变研究。E-mail: liyouli@pku.edu.cn
  • 基金资助:
    国家自然科学基金(40971001)

Gullies Evolution and Fault Activities in Dushanzi, Xinjiang

QIAN Mang, LI Youli, SI Supei, LU Shenghua, WANG Yiran   

  1. College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
  • Received:2011-12-07 Revised:2012-02-19 Online:2012-05-20 Published:2012-05-20
  • Supported by:
    National Natural Science Foundation of China, No.40971001

摘要: 独山子背斜是天山北麓三排褶皱带中西北端的背斜,其北翼发育一条逆冲断层。断层的活动在奎屯河阶地和冲积扇上形成了高度小于20 m的断层陡坎。陡坎上游冲积物中发育多条冲沟,冲沟根据长度可分为7 组。探槽揭示了独山子背斜北翼断层最新的两次活动,其中较早的断层活动时间为3110±40 a BP。根据这次断层活动触发的冲沟的平均长度得到冲沟溯源侵蚀的速率为38 mm/a。由该溯源侵蚀速率,计算出每组冲沟发育的时间,分别约为1170 aBP,3110 a BP,7200 a BP,12570 a BP,14990 a BP,30570 a BP,37750 a BP,可能代表断层多次活动的时间。断层最新一次活动的时间与本文探槽研究限定时间段相符,其他最近的三次活动时间与前人探槽研究的结果相符。说明在特定条件下,用断层上升盘冲沟平均溯源侵蚀速率推算断层活动时间是可行的。

关键词: 冲沟, 溯源侵蚀, 断层活动事件, 独山子背斜, 独山子断层

Abstract: Dushanzi anticline is the northwestern fold of the three fold belts in north Tianshan Mountains. A thrust fault has developed in the north limb of the fold. The fault movement caused scarps with a height of less than 20 m in the terraces and alluvial fans of Kuitun River. Gullies have developed on the upper stream alluvium of the scarp, which can be divided into 7 groups by length. Trenches revealed two latest faulting events of the north limb fault in Dushanzi anticline, the former occurred at 3110?40 a BP. The headwater erosion rate is 38 mm/a, deduced from the average length of gullies triggered by faulting. Based on the headwater erosion rate, the time of formation can be calculated for each group of gullies (1169 a BP, 3110 a BP, 7203 a BP, 12573 aBP, 14992 a BP, 30568 a BP, and 37745 a BP), which may coincide with occurrences of faulting events. The latest faulting age derived from headwater erosion rate is consistent with that discovered from trenches, and another three latest events are consistent with the previous studies on trenching. This result shows that under specific conditions it is applicable to estimate the time of faulting based on headwater erosion rate of gullies on uplift wall.

Key words: gully, headwater erosion, faulting event, Dushanzi anticline, Dushanzi fault