大陸移動と火成活動

概要

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Various geological and paleomagnetic evidences strongly support the concept of continental drift since the Middle Mesozoic. It might be taken, as already stressed by a number of authors, as a geological "fact". The theory of ocean-floor spreading and plate tectonics to date seem, however, insufficient to interprete the cause and real mechanism of continental drift. In my opinion the decisive cause of continental drift was the slight expansion of certain horizon within the upper mantle due to heat accumulation during relatively quiet periods since the Latest Precambrian through the Late Paleozoic. The essential mechanism of continental drift seems to have been the " active" advance of continental lithospheres, through the overriding of neighbouring oceanic (Pacific) floors beneath them, corresponding to the new generation and spreading of the Atlantic and Indian ocean floors. As well-known, several localities at the tails of drifting continents are characterized by the Early〜Middle Mesozoic basic (tholeiitic) volcanic eruptions, the frontal regions of drifting continents adjacent to the Pacific being, on the other hand, marked by calcalkaline, predominantly intermediate〜acid volcanism and plutonism since the Late Mesozoic. Some genetial problems concerning these contrasted magmatisms are presented in term of the above-mentioned cause and mechanism of continental drift.
地学団体研究会の論文
1972-05-25