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为了揭示孟加拉湾盆地的构造特征和中生代以来的动力学演化,对研究区卫星重力数据进行滤波、梯度和延拓等深度处理,对相关地震剖面进行标准化处理,在研究区建立了8条主干剖面.自由空气重力异常及其深度处理结果显示在盆地西部、海岭内部及盆地东部分别发育北西向破碎带、近东西向断裂和北东向线性构造,分别反映了海底北西向扩张、海岭侵位及印度洋洋壳北东向俯冲的影响.主干剖面经标准化处理后划分出上白垩统-第四系5套层系,结合重力异常与地层厚度,将孟加拉湾盆地划分为西部坳陷、85°E海岭隆起、中央坳陷、90°E海岭隆起和若开坳陷5个构造单元.85°E海岭隆起内发育的多个孤立高隆起是热点幕式喷发的响应,控制着碰撞前盆地“西厚东薄”的沉积格局,而碰撞后孟加拉扇体系在始新世至中新世期间一直向南迁移,未受到海岭的明显影响.90°E海岭南段(7°~14°N)的俯冲消减促进了安达曼增生楔的向西生长,北段(14°~20°N)的俯冲作用则控制着若开坳陷、印缅增生楔和孟加拉湾盆地沉积中心的演化.构造特征和动力学演化分析表明盆地经历了原始大洋盆地(晚白垩世-早渐新世)和残留洋盆地(晚渐新世-)2个主要演化阶段.
In order to reveal the tectonic characteristics of the Bay of Bengal and the dynamic evolution since the Mesozoic, the satellite gravity data in the study area were filtered, graded and extended. The relevant seismic sections were normalized and eight main sections were established in the study area. Free-air gravity anomalies and their depth-treatment results show that the NW-trending crust, NE-trending faults and NE-trending linear structures are developed in the western part of the basin, in the interior of the Ridge and in the eastern part of the basin, respectively reflecting the northwest expansion of the seafloor, the ridge encroachment and the Indian Ocean The northeastern subduction of the oceanic crust is normalized and the upper Cretaceous-Quaternary system is divided into five sets. Based on the gravity anomalies and the thickness of the strata, the Bay of Bengal Basin is divided into the western depression, the 85 ° E ridge uplift , Central Depression, 90 ° E Ridge Uplift and 5 structural units in the Wakahae Depression.The multiple isolated uplifts developed in the 85 ° E Ridge Uplift are the responses of hot-curtain episodes, controlling the pre- East Thin "deposition pattern, and after the collision Bengal fan system during the Eocene to the Miocene migration has been southward, without being significantly affected by the ridge .90 ° E The subduction reduction of Lingnan section (7 ° ~14 ° N) promoted the westward growth of the Andaman accretion wedge. The subduction of the northern segment (14 ° -20 ° N) controlled the Ruoka depression, the Indo-Myanmar accretion wedge and The evolution of the sedimentary center in the Bay of Bengal.The tectonic characteristics and dynamic evolution of the basin indicate that the basin underwent two major stages of evolution in the primitive oceanic basin (Late Cretaceous-Oligocene) and the residual ocean basin (Late Oligocene).