边缘海盆地的形成机制及其对中国东南地质研究的启示

FORMATION OF MARGINAL BASINS AND ITS IMPLICATION TO THE TECTONIC EVOLUTION OF SOUTHEAST CHINA

虽然有关边缘海的成因解释有“捕获机制”、弧后扩张（被动、主动）机制、陆内应力传播机制等，但迄今尚未有一种机制能统一解释所有边缘海的成因。边缘海的成因不仅是经典的沟－弧－盆二维剖面问题，而应是一个包括平面图上大陆板块的变形在内的三维问题。边缘海的研究能给我国东部、特别是东南地区地质研究提供有益的启示，它包括：慎重鉴别古岛弧、对变质带、古洋壳及洋盆规模；充分注意小块体之间的碰撞，古转换断层在本区晚中生代岩浆活动、大陆增生过程中起重要作用；相关盆地内的沉积物记录着丰富的大陆碰撞。

Although a large variety of mechanisms have been proposed to account for the formation of marginal basins, including “entrapment” origin, back arc spreading and intraplate stress propogation, etc., no solution has ever reached for the formation and evolution for marginal basins in the western Pacific. The study of marginal basins should take into account the mechanisms for continental deformation, thus constitute a 3-D approach to the problem. Recent contributions in the study of marginal basins also shed new light in the study of tectonic evolution of Southeast China. Cautions should be taken in the identification of ancient volcanic arcs, subduction zones and the reconstruction of ocean basins. The combined effect of NNE trending transform faults related to Paleo tethys and the movement of Paleo Pacific plates play a significant role in the formation of huge Mesozoic igneous activities. Transition from transform fault to subduction system constitutes a unique form of continental accretion for Southeast China and its adjacent areas. Sediment record in the related basins will provide substantial information for the related continental collision and mountain building and erosion process.