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一、前言西太平洋的小洋盆(或边缘海)与活动的岛弧海沟系伴生,并位子被动的大陆边缘的一侧。虽然这些小洋盆在构造上是大洋性质的,但在海底深度、充填沉积物的厚度、基底高程、重磁力异常以及热流等方面都有很大的变化。对于它们的成因则有以下种种解释:由于岛弧的形成,包围了老的洋壳;由于岛弧的移动(海底扩张)产生了新的地壳;由于大洋化使陆壳或准陆壳沉降或解体;由于强烈火山作用所引起的复活;或者是由于这些机制的任意结合。
I. INTRODUCTION The small ocean basins (or marginal seas) in the western Pacific Ocean are associated with the active island arc trench and one side of the passive continental margin. Although these small oceanic basins are structurally oceanic, they vary widely in terms of seafloor depth, thickness of fill sediment, basement elevation, gravity and magnetic anomalies, and heat flux. For their causes, there are the following explanations: the formation of the island arc surrounded the old oceanic crust; the new crust was created by the movement of the island arc (seafloor expansion); the continental crust or quasi-continental crust subsided due to oceanification or Disintegration; resurrection caused by intense volcanism; or due to any combination of these mechanisms.