Abstract
(I) Analogy of the pattern of tectogenesis (1) The most important ground for the writer's assertion that the Green Tuff movement began with collapse lies in the character of the basal conglomerate. From the fact that a similar conglomerate is found in the sedimentary basins of the Late Mesozoic to Early Paleogene period, the writer presumed that the tectogenesis of this period must have begun also with collapse. Later, his presumption was corroborated by MURAKAMI and others. (2) The Green Tuff movement occurred cutting the pre-Neogene tectogenic belt. In this respect, the Green Tuff movement is identical with the Late Mesozoic〜Paleogene tectogenesis. (II) Tectogenic correspondence between Inner Zone and Outer Zone The tectonic movement of the Outer Zone during the Late Mesozoic〜Early Paleogene period is characterized by subsidence, as exemplified by the Shimanto geosyncline and other basins. The Green Tuff movement took place mostly in the Inner Zone, whereas in the Outer Zone sedimentary basins were developed, accompanied by almost no igneous activity. When such a tectogenic correspondence is considered for the later period, the Inner Zone of the Late Neogene〜Quaternary period may be defined as a volcanic belt represented by the active volcanoes distributed on land, and the Outer Zone as a subsidence belt represented by the submarine trenches observed today. The above-mentioned correspondence is applicable only when the tectogenesis of the near-ocean side of the Inner Zone is dealt with. In actuality, however, the tectonic movement of the Inner Zone covers a vast area of the continent more than 1,000 km in width, as shown in Figs. 1, 2. This fact makes it difficult to explain those tectonic movements by a single plane of deep-seated earthquakes as advocated in the theory of the so-called plate tectonics. (III) The progress of the igneous activities in the three tectonic movements of the Inner Zone since Late Mesozoic shows a tendency of gradual basification. BELOUSSOV'S view that the igneous activities on the earth have been gradually basified since Mesozoic seems to be based on some areas centering on the rift systems. The areas discussed in the present paper are island arcs and adjacent areas, so that it is possible that the basification in these areas progressed more slowly than in the rift areas, and was delayed to the latter half of the Cenozoic area.
