Abstract: Structural geometry and kinematics analysis show that lower Triassic strata are characterized by nearly N-S trending gently anticlines, while the middle-upper Triassic and Paleozoic strata have sub-E-W or NE trending in the uplift of the Sichuan Basin. These structural patterns indicate that there was a “tectonic decoupling” event during Triassic. Based on structural and sedimentary analyses, it is concluded that event briefly responded to the Indo-China orogeny and resulted in the initiation of the Weiyuan uplift. The close-relationship between the folds and fractures may have important applications in hydrocarbon exploration in Paleozoic strata of the Weiyuan uplift.

Key words: Weiyuan uplift, Triassic, tectonic decoupling, Indo-China, paleo-uplift, reservoir

摘要： 通过对四川盆地中央平缓区内威远隆起三叠系地层的构造几何学和运动学解析发现, 下三叠统地层呈近南北走向的宽缓褶皱变形, 而其上覆中、上三叠统地层和下伏古生界地层均为近东西和北东走向的褶皱?断裂构造形迹, 表明下三叠统嘉陵江组地层构造变形与上下层系的构造变形解耦, 分析认为该构造解耦是早三叠世末期印支构造变形事件的重要响应和记录, 保存于三叠系地层中的这一构造解耦事件暗示威远隆起是印支构造运动的直接产物, 是印支期构造古隆起。从褶皱样式与破裂相关性分析, 认为威远褶皱型古隆起及其相伴生裂缝是威远古生界气藏赋存的重要方式。

关键词: 威远隆起, 三叠系, 构造解耦, 印支期, 古隆起, 油气藏