浙闽近海瓯江凹陷新生代地质构造发展特征

瓯江凹陷的上白垩统和下第三系建造序列具体反映了断凹演化。断陷阶段分为初始开裂、强裂裂开、全面裂陷和频繁振荡。凹陷阶段沐现了海浸—沉降—填满全过程,凹陷由数个剖面上呈箕状的菱形次级小断块组成。这种结构及发展特征既与弧后垃开体制有关,也与瓯江凹陷处于中生代地体碰撞带有关。瓯江凹陷是东海陆架弧后裂陷盆地的一部分。

CHARACTERISTICS OF CENOZOIC GEOLOGIC AND TECTONIC DEVELOPMENT OF THE OUJIANG DEPERESSION IN ZHEJIANG-FUJIAN OFFSHORESEA

The formation sequence in the Oujiang Depression obviously reflects the evolution of the depression from faulting-depressing to depressing during the late Cretaceous and Paliogene. The faulting-depressing stage has undergone several puocesses:1) initial rifting,2) intense breakup,3) overall downfaulting,4) frequent oscillation.The depressing stage has proceeded in the Whole process from transgression through subsidence to filling up of the depression. Structurally the Oujiang Depression may be composed of several rhombic small fault-blocks, showing a dustpan structure in the profile.This structure and the geological deuelopment of the depression are related to a backard extension regime and to the Mesozoic terrene collision zone,where the Oujiang Depression is situated.Again,the depression is a part of the backarc rifted basin on the East China Sea shelf.