弧后盆地

有关岛弧的研究,在三十年代早已开始了.1930年时,荷兰一位地球物理学家在研究重力异常时发现,在印尼南部的诸岛形成了一个弧状的构造,称它为岛弧.而且发现了它以南弧形的爪哇海槽,这是个很深的海槽,在它北坡下有个很大的重力异常带.这个海槽发现后,许多地质学家普遍认为岛弧在海洋地质上是个很重要的现象,与造山运动有关.

BACK-ARC BASINS

This article reviews briefly current data and ideas on back-arc basins and suggests that such basins in the Western Pacific might indeed owe their origin to back-arc spreading as postulated by D. Karig(1971).Those basins commonly have an oceanic curst, recognizable magnetic lineations, and high heat-flow. However, not all back-arc basins are so characterized. The Caribbean basins, for example, have neither magnetic lineation nor apparent crustal ages as predieted by a spreading model(Edgar, Saunders, et al., 1973).Recent multi-channel seismic data suggest that the previous deep-sea drilling there has only reached mid-Cretaceous basalt extruded during mid-plate volcanism;the drilling has failed to sample the true oceanic basement(e.g., L. Montadert, personal communication).Current speculations regard the Caribbean as a fragment of the Pacific curst that has incidentally been trapped behind the Caribbean Arc,(e.g., E. L. Winterer, personal communication);the geological history of the Caribbean crust might be comparable to that of the Nauro Basin of the South Pacific(Larsen, Schlanger, et al., 1980).