论文部分内容阅读
介绍了国内外有关东海地壳结构特征的调查研究状况,并利用前人大量的调查研究成果,根据自西向东地壳速度结构的差异,将东海海区划分为东海陆架区、冲绳海槽区、琉球岛弧-海沟区三部分。东海陆架区主要由沉积盖层(速度为5.8～5.9km/s)、基底层(速度为6.0～6.3km/s)和下地壳层(速度为6.8～7.6km/s)三个速度层组成,属于典型的大陆型地壳。冲绳海槽则位于大陆地壳和大洋地壳的过渡地带,它仍然具有大陆地壳的结构特征,并无洋壳的形成,但在海槽的轴部地壳已经减薄。琉球岛弧-海沟区的地壳结构总的来说属于过渡型地壳,但在海沟靠洋一侧已属于大洋型地壳,而从琉球海沟往东的西北菲律宾海盆,就完全属于典型的大洋地壳。
This paper introduces the research status of the crustal structure in the East China Sea at home and abroad, and makes use of a large number of previous research results. According to the differences in crustal velocity structure from west to east, the East China Sea is divided into the East China Sea shelf area, the Okinawa trough area, Arc - trench area three parts. The East China Sea continental shelf is mainly composed of three velocity layers: sedimentary cover (velocity 5.8-5.9km / s), basement (velocity 6.0-6.3km / s) and lower crust (velocity 6.8-6.6km / s) , Is a typical continental crust. The Okinawa Trough is located in the transition zone between the continental crust and the oceanic crust. It still has the structural characteristics of the continental crust and does not have the formation of the oceanic crust. However, the crust has been thinned at the axis of the trough. The Ryukyu Island Arc-Trench District crustal structure generally belongs to the transitional crust, but it belongs to the oceanic crust on the oceanic side of the trench. The northwestern Philippine basin eastward from the Ryukyu Trench belongs to the typical oceanic crust.