Measurement of terrace deformation and crustal shortening of some renascent fold zones within Kalpin nappe structure  

作　　者：YANG XiaoPing RAN YongKang CHENG JianWu CHEN LiChun XU XiWei 

机构地区：[1]Institute of Geology,China Earthquake Administration,Beijing 100029,China

出　　处：《Science China Earth Sciences》2007年第1期33-42,共10页中国科学（地球科学英文版）

基　　金：Supported by the National Natural Science Foundation of China (Grant No. 40572126);China Earthquake Administration under project Integrated Investiga-tion of Seismogenic Structures for Intermediate-Strong Earthquakes in Jiashi-Bachu of Xinjiang Uygur Autonomous Region.

摘　　要：The Kalpin nappe structure is a strongest thrust and fold deformation belt in front of the Tianshan Mountains since the Cenozoic time. The tectonic deformation occurred in 5―6 striking Meso-zoic-Cenozoic fold zones, and some renascent folds formed on the recent alluvial-proluvial fans in front of the folded mountains. We used the total station to measure gully terraces along the longitudinal to-pographic profile in the renascent fold zones and collected samples from terrace deposits for age de-termination. Using the obtained formation time and shortening amount of the deformed terraces, we calculated the shortening rate of 4 renascent folds to be 0.1±0.03 mm/a, 0.12±0.04 mm/a, 0.59±0.18 mm/a, and 0.26±0.08 mm/a, respectively. The formation time of the renascent folds is some later than the major tectonic uplift event of the Qinghai-Tibet Plateau 0.14 Ma ago. It may be the long-distance effect of this tectonic event on the Tianshan piedmont fold belt.The Kalpin nappe structure is a strongest thrust and fold deformation belt in front of the Tianshan Mountains since the Cenozoic time. The tectonic deformation occurred in 5–6 striking Mesozoic-Cenozoic fold zones, and some renascent folds formed on the recent alluvial-proluvial fans in front of the folded mountains. We used the total station to measure gully terraces along the longitudinal topographic profile in the renascent fold zones and collected samples from terrace deposits for age determination. Using the obtained formation time and shortening amount of the deformed terraces, we calculated the shortening rate of 4 renascent folds to be 0.1±0.03 mm/a, 0.12±0.04 mm/a, 0.59±0.18 mm/a, and 0.26±0.08 mm/a, respectively. The formation time of the renascent folds is some later than the major tectonic uplift event of the Qinghai-Tibet Plateau 0.14 Ma ago. It may be the long-distance effect of this tectonic event on the Tianshan piedmont fold belt.

关 键 词：TIANSHAN Mountains Kalpin NAPPE structure active FOLDS TERRACE folding CRUSTAL shortening. 

分 类 号：P542[天文地球—构造地质学]