东海陆架盆地地质结构及构造演化

东海陆架盆地发育于东海大陆架之上,是一个复合型沉积盆地。盆地的西侧是浙闽隆褶带,东侧是钓鱼岛岩浆岩带,盆地从西至东呈现为凹-凸-凹的格局,南北差异明显,总体地质构造格架表现为东西分带、南北分块的特征。该盆地存在元古代的变质基底,是浙闽沿海陆区出露的深变质岩系向东的延伸,这套古老的变质岩系组成了陆架盆地的主要基底。盆地在垂向上表现为明显的多层结构。除古生界地质结构尚待证实外,中生界明显为裂谷型二层结构,新生界为三层结构。盆地结相特征受控于特定的构造演化过程。中生代以前不同性质的地体增生和中生代以来太平洋板块的运动方向不断变化以及印度板块作用造成的地壳蠕散是控制盆地形成和树造演化的主要体制,使盆地构造演化表现为多阶段、多种构造体的明显特征。

The Geological Structure and Tectonic Evolution of the East China Sea Shelf Basin

The East China Sea shelf basin,as a composite sedimentary basin,is occurrred on the East China Sea shelf.On the west of basin is Min - Zhe upfold, while Diao - yudao magmatic rock belt on the left. The basin shows a concave - convex - concave pattern from west to east. The differences between the south and north are obvious. The total geological structure characterized to be belted from east to west and blocked from south to north. The metamorphic basement of Proterozoic Era existed in this basin, and was believed to be the eastern prolongation of the deep - metamorphic rock systems which occurred along the coastland of Min - Zhe area. The main basement of the shelf basin was consisted of this ancient metamorphic rock system. The vertical section shows and obvious multiple - layer structure. The Mesozoic Erathem shows an obvious rift - valley two - layer structure, while the Cenozoic Erathem shows a three - layer structure. But the geological structure of the Palaeozoic Erathem was still not certified. The characterize of the basin structure was enslaved to the process of the tec- tonic evolution. The accretions of the terranes of the different properties before dMesozoic Era, the change of the drift direction of the Pacific Ocean plate and the lithosphere' s creep deformation conduced by the India plate ater Mesozoic Era contributed to the formation of the basin and the tectonic evolution, thus characterized the tectonic evolution of the basin as multiple - phase and complex - structure terranes.