The current hypothesis of plate tectonics and the associated hypotheses of seafloor spreading and continental drift are found to be inadequate. They do not explain large bodies of data derived from geological, biological, and geophysical sources; nor has an acceptable mechanism been advanced.

Therefore, the following new model is proposed. (1) Volcanism, in bringing solid matter out of the mantle, has also brought water to the surface in sufficient volume to form the seas; other volatile materials also have been brought to the surface. The volatile and liquid materials remain on the surface because they are too light to restore balance of mass within the mantle; consequently, restoration is through subsidence of crust. Thus the ocean basins gradually have subsided as water has accumulated on the surface to form the present seas. (2) Stresses resulting from extensive and severe subsidence induce the formation of fracture zones. (3) Subsequent slower downwarping results in transverse surface fractures, through which magma flows to form magnetic anomalies. (4) Similar but bil teral subsidence leads to the formation of the so-called midocean ridges. (5) Because volcanism centers around present or past island arcs, growth of continental regions occurs peripherally. As a consequence of their continual seaward growth, suitable asthenospheric materials capable of moving into the magma chambers are drawn ultimately from adjacent suboceanic regions. (6) Thus volcanism eventually leads to subsidence, which in turn induces earthquakes, fracture zones, magnetic anomalies, midocean ridges, and other characteristic features of the ocean floors.