川西龙门山冲断系构造样式与前陆盆地演化  

STRUCTURAL STYLES OF THE LONGMENSHAN THRUST BELT AND EVOLUTION OF THE FORELAND BASIN IN WESTERN SICHUAN PROVINCE, CHINA

作　　者：刘和甫[1] 梁慧社[1] 蔡立国 沈飞 

机构地区：[1]中国地质大学

出　　处：《地质学报》1994年第2期101-118,共18页Acta Geologica Sinica

基　　金：国家自然科学基金(9487002)

摘　　要：龙门山冲断系构造样式按卷入深度,可分为基底冲断层-挤压断块与盖层褶皱-冲断系两大类。在剖面上将龙门山构造带划分为5个带。龙门山冲断系扩展顺序分为:前期由推覆作用引起的前展式扩展;后期由重力滑覆作用引起后展式扩展。据平衡剖面及构造复原,龙门山冲断系总滑移量为120km。川西特提斯域构造演化可划分为大陆裂解、洋-陆俯冲、陆-弧碰撞、冲断选山及川西隆起5个阶段。The formation of the Longmenshan orogenic thrust belt and the evolution of its foreland basins record the tectonic evolution of the Tethys domain in western Sichuan Province, China. Structural styles of the Longmenshan thrust belt can be classified into two major groups according to the depth of their involvement: basement thrusts and compressive blocks; the fold-thrust system in the cover. The Longmenshan thrust system consists of tectonic elements. From west to east, they are: (1) flysch fold-thrust belt, (2) basement thrusts, (3) thin-skinned imbricate thrusts, duplex system and klippes, (4) back-thrusts and triangle zone, and (5) foredeep synclines. The thrusts propagation in Longmenshan is piggy-back at the early stage due to pushing and overstep at the late stage due to gravity sliding. Balanced cross-sections and palinspastic reconstruction reveal that the displacement of thrusts in the region amounts to over 120km. The tectonic evolution of the Longmenshan thrust system consists of five stages: (1) continental break-up, resulting in the formation of a passive margin along the western margin of the Yangtze Block; (2) ocean-continent subduction, forming the Yidun arc-trench system in western Sichuan; (3) continental collision, giving rise to the Shongpan-Garze foreland flysch basin or remnant basin; (4) orogenic thrusting, resulting in formation of a foreland molasse basin in the front of Longmenshan; (5) uplift of western Sichuan, forming sliding thrusts and lag normal faults.

关 键 词：冲断层系 构造样式 前陆盆地 断层 

分 类 号：P532.3[天文地球—古生物学与地层学]