传统的地槽地台说认为,地槽旋回未期发生造山运动,当地台阶段降临时,构造活动便衰减了。衰减可以是迅速的,也就是说,地槽阶段一结束,下一构造旋回一开始,便可见到典型地台的构造体制。乌拉尔即为一例,此处从阿尔卑斯旋回开始就形成了地台。在另外的场合,这种衰减来得很慢,因此,在地槽状态和典型的地台状态之间,可以分出一个中间阶 The traditional geosyncline platform said that there was no orogeny occurred during the geosyncline cycle, and the tectonic activity was attenuated when the local platform stage came. Attenuation can be rapid, that is to say, as soon as the geosyncline stage is over, the next stage of structural rotation begins, the typical structure of the platform can be seen. Ural, for example, forms the platform from the beginning of the Alps cycle. On other occasions, this attenuation is very slow, so that between the earth-trough state and the typical ground-state condition, an intermediate step