The formation and evolution of the Qiaojia pull-apart basin,North Xiaojiang Fault Zone,Southwest China  

作　　者：LI Tian-tao PEI Xiang-jun HUANG Run-qiu JIN Long-de 

机构地区：[1]State key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 61oo59,China [2]Georgia Institute of Technology,Atlanta 30332,Georgia,USA

出　　处：《Journal of Mountain Science》2016年第6期1096-1106,共11页山地科学学报（英文）

基　　金：funded by the Major State Basic Research Development Program of China(2013CB733200);the State Key Program of National Natural Science of China(41572302)

摘　　要：Sedimentary sequences with drastic thickening over short distances have been observed in Qiaojia County,Yunnan Province,Southwest China.These are related to a pull-apart basin controlled by the Xiaojiang strike-slip fault.Our field investigations include determining the surface characteristics of the Qiaojia basin which consists of three terrace sequences and a series of alluvial fans.Several drill holes were used to reveal the internal structure of the basin.The results suggest that the basinal sediments are over 300 m thick.From bottom to top,they can be classified into five different units.We inferred that the units of lacustrine sediments are deposited in a paleolake which was formed by a paleo-landslide.Accelerator mass spectrometry radiocarbon dating(AMS ^(14)C dating) was used to estimate the ages of the terrace and lacustrine sediments.We use the results to infer that the paleo-lake has existed about 15,000 years and that the Qiaojia basin was uplifted at an average rate of 3.3 mm/a.Furthermore,we then model the evolution process of the basin and interpreted 6 phases of development.

关 键 词：Pull-apart basin Xiaojiang fault STRIKE-SLIP EVOLUTION TERRACE Dammed lake 

分 类 号：P542[天文地球—构造地质学]