Depositional architecture of the Tertiary tectonic sequences and their response to foreland tectonism in the Kuqa depression, the Tarim Basin  

作　　者：林畅松 肖建新 刘景彦 陈建强 张燕梅 纪云龙 

出　　处：《Science China Earth Sciences》2002年第3期250-258,共9页中国科学（地球科学英文版）

基　　金：This work was supported by the Ministry of Science and Technology of China (Grant No.G1999043304).

摘　　要：The Tertiary Kuqa depression is a foreland basin generated by flexural subsidence resulting from the southward thrusting of the southern Tianshan Mountains. Tertiary basin fills of the depression can be classified into four tectonic sequences bounded by gentle angular unconformities. The sequences are composed of two parts, the lower transgressive and the upper progradational successions, which are separated by a regional maximum transgressive surface. The development of these sequences is attributed to the foreland tectonic process from flexural subsidence caused by thrust loading to rebounded uplift due to the erosion and stress release. The generation of the angular unconformities defining the tectonic sequences has been interpreted as the result of the rebounded uplift and the following thrusting. It has been found that there is a significant difference in depositional pattern between the northeastern and the northwestern margins. The relatively strong thrusting and mountain building occurring along the northwestern margin resulted in the development of thick-bedded alluvial fan and angular unconformities. The northeastern margin, in contract, lacks thick alluvial fan accumulation due to weak thrusting. This difference is likely related to the pre-existing east-west partition of the basin basement.The Tertiary Kuqa depression is a foreland basin generated by flexural subsidence resulting from the southward thrusting of the southern Tianshan Mountains. Tertiary basin fills of the depression can be classified into four tectonic sequences bounded by gentle angular unconformities. The sequences are composed of two parts, the lower transgressive and the upper progradational successions, which are separated by a regional maximum transgressive surface. The development of these sequences is attributed to the foreland tectonic process from flexural subsidence caused by thrust loading to rebounded uplift due to the erosion and stress release. The generation of the angular unconformities defining the tectonic sequences has been interpreted as the result of the rebounded uplift and the following thrusting. It has been found that there is a significant difference in depositional pattern between the northeastern and the northwestern margins. The relatively strong thrusting and mountain building occurring along the northwestern margin resulted in the development of thick-bedded alluvial fan and angular unconformities. The northeastern margin, in contract, lacks thick alluvial fan accumulation due to weak thrusting. This difference is likely related to the pre-existing east-west partition of the basin basement.

关 键 词：TECTONIC sequence  DEPOSITIONAL architecture  TERTIARY KUQA depression. 

分 类 号：P542[天文地球—构造地质学]