川东—武陵地区构造格局及其演化

陆内变形是现今大陆动力学研究的重要内容之一。川东-武陵地区位于扬子地块的内部，远离板块边界，是研究陆内变形的绝佳场所。通过野外断裂构造详细的解析、褶皱构造的形态分析以及沉积地层接触关系的研究，建立了川东-武陵地区显生宙构造格局，探讨了多期构造演化过程。晚中生代以来的两次构造作用奠定了研究区的构造格架，认为滑脱层的深度及数量从根本上控制了川东-武陵地区侏罗山式褶皱变形的差异，褶皱与断裂构造几乎同时形成，川东地区的隔挡式褶皱为单层滑脱变形的结果，而武陵地区的褶皱构造是由于多层次滑脱背景下、差异隆升剥蚀造成的不同构造层次褶皱出露的结果。结合区域地质演化，提出川东-武陵地区显生宙时期主要经历了五期构造演化。晚志留-中泥盆世、石炭纪末和中、晚三叠世之交，研究区均以整体的抬升作用为主，不发育任何褶皱构造；晚侏罗-早白垩世发生大规模褶皱-逆冲作用；新生代晚期，受印度与欧亚大陆汇聚作用的影响，区内断裂带走滑方向发生反转，早期构造被强烈改造。 

TECTONIC ARCHITECTURE AND EVOLUTION OF THE EASTERN SICHUAN-WULINGSHAN AREA, SOUTH CHINA

Intracontinental deformation is one of the important contents in continental dynamics research. The eastern Sichuan-Wulingshan area is located in the interior of the Yangtze Block, far away from the plate boundary, which is an excellent place to study the intracontinental dynamics. On basis of kinematic analysis of faults, morphological analysis of the folds, and contact relationship of the sedimentary strata in the field, we established the Phanerozoic tectonic architecture and discussed the multiple evolutions of the eastern Sichuan-Wulingshan area. Two tectonic events since the Late Mesozoic have laid the tectonic framework of the study area. The fold deformation differences of the eastern Sichuan-Wulingshan area were fundamentally controlled by the depth and quantity of decollement layers. Folds and faults were formed at the same time. The ridge-like folds in the eastern Sichuan area were the result of single-layer slip deformation, while the fold structures in the Wulingshan area were the result of the exposure of folds at different structural levels by different uplifts and denudations under the multi-layer slip background. Combining with the regional evolution, we proposed a five-stage tectonic evolution model of the eastern Sichuan-Wulingshan area in the Phanerozoic. The first three stages (Late Silurian-Middle Devonian, the end of the Carboniferous, and the Middle-Late Triassic) were dominated by regional uplift, without any folds. Then, large-scale folds and thrusts were developed at the fourth stage in the Late Jurassic-Early Cretaceous. Ultimately, due to the influence of the convergence of the India continent and Eurasia continent, the slip direction of the fault was reversed and the early structure was strongly reformed in the late Cenozoic.