新疆和静地区新生代原型盆地恢复及后期构造破坏

焉耆盆地和静北部地区发育一个现今地貌上的小型背驮盆地。新生代地层中砾岩砾石成分稳定，以变质岩和沉积岩成分居多，岩浆岩很少；砂岩成熟度普遍低，长石和石英含量少，岩屑含量居多，砂岩成熟度从盆地早期渐新统—中新统的玛萨盖特组到上新统—更新统安吉然组下降。该盆地内部及其周缘地区新生代地层古水流方向主要向南，显示物源是北部的南天山地区，直至更新世时期该背驮盆地并未单独发育，而是焉耆盆地北部的一部分。由于天山地区的侧向扩展作用，更新世以来本区形成了典型的逆冲断裂带，北部的逆冲断层使中泥盆统逆冲到安吉然组之上，中部的一条逆冲断裂使下伏的中泥盆统和花岗岩体抬升，形成了现今的地貌；南部的逆冲断层作用在安吉然组内形成了南陡北缓的断层相关褶皱。和静地区的新生代变形是由北向南进行的，具有西强东弱的特点，西部地区的构造缩短率大于东部地区。

Reconstruction of Cenozoic original basin and its structural destruction in Hejing area, Xinjiang province

The North Hejing basin located in the north of the Hejing area now is a piggyback basin. Gravels components from the Cenozoic strata are mainly composed of metamorphic rocks and sedimentary rocks with little magmatic rocks. The low maturity of sandstones are characterized by low contents of quartz, feldspar and large amount of rock debris. From Oligocene-Miocene Masagaite Formation to Pliocene- Pleistocene Anjiran Formation, the maturity of the debris decreases. The paleocurrent direction of Cenozoic strata in the internal and around basin was from north to south, which indicates the southern Tianshan Mountain was the source region of Cenozoic strata. Until Pleistocene Epoch, there is no individual piggyback basin in the northern Yanqi Basin. Because of the lateral spreading process of the Tianshan Mountain caused southward thrust wedge belt in the Northern Hejing area. And the northern thrust uplifted the middle-Devonian upon the Anjiaran Formation, while central thrust fault uplifted the middle-Devonian and the granite, formed present topographical feature on the ground. In addition, southern thrust fault caused a series of folds in the Anjiran Formation characterized by steep dip angle in the south section and gently angle in the north. During the Cenozoic, the age of deformation event is older in the northern area than southern in Hejing district. Furthermore, the deformation in the western area is stronger than eastern and the shorten ratio related to structural activities is larger too.