西北太平洋边缘新生代盆地成因(上):成盆机制述评

GENESIS OF CENOZOIC BASINS IN NORTHWEST PACIFIC OCEAN MARGIN(1):COMMENTS ON BASIN-FORMING MECHANISM

全面地简述了西北太平洋边缘新生代盆地成盆机制各种学说 ,强调了成盆机制分析原则。按弧后主动扩张说、弧后被动拉张说、局部区域左行挤出说等 ,演绎出的盆地空间几何形态与实际情形不符 ,演绎出的块体运动及位移在空间上不能平衡。局部区域的右行剪切拉分说是揭示西北太平洋边缘盆地成因的良好开端。以日本海和南海为例 ,讨论了边缘海“洋壳基底”性质 ,认为所谓的“洋壳”实为变薄的陆壳。现行边缘海的年龄值没有实际意义。

This article briefly describes variou hypotheses of the genesis of Cenozoic basins in northwest Pacific margin and emphasizes the analysis principle of basin genesis.The basins' spatial geometric forms deduced from the hypotheses of back arc active extension,back arc passive tension and regional left lateral extrusion do not coincide with the actural ones;and the deduced block movement and displacement do not balance in space.The hypothese of regional right lateral shear pulling apart is the starting point in revealing the genesis of the basins in the northwest Pacific Ocean margin.Finally the feature of ocean crust of marginal sea basins was discussed with Japan Sea and South China Sea as examples.It is suggested that the so called ocean crust is acturally the thinned continental crust.