日本での地向斜概念の発展とプレートテクトニクス

抄録

The concept of geosynclines was born in the middle of the nineteenth century had been a fundamental concept in geology for more than one hundred years. Geosynclines had been understood as the places where mountainbuilding occurred. However many geologists thought that mountain-building forces existed outside geosynclines. Many mountain-building theories as earth contraction, continental drift, etc. coexisted before the advent of plate tectonics. When plate tectonics which was applied to mountain-building appeared, it was regarded as one acceptable theory of mountain-building at first. Therefore the concept of geosynclines did not conflict with plate tectonics in the West. After World War II, the Japanese geological community was involved in a passionate movement for democracy and the members of this political group tended to apply their own scientific theories. In particular, they came to the idea that geosynclines possessed mountain-building forces within them. According to this idea, in the center of geosynclines granite is made from geosynclinal deposits, and it is so much lighter than other materials that it gets enough buoyancy to upheave the mountain surrounding it. This idea, which became dominant among Japanese geologists, was called geosynclinal mountain-building theory. It gradually grew into a kind of paradigm. In contrast, plate tectonics account for mountain-building as a conquence of plate motion. When plate tectonics was introduced into Japan in the end of 1960s, the adherence of the Japanese geosynclinal mountain- building theory therefore did not accept plate tectonics. Consequently, it was not until the middle of 1980s that plate tectonics was generally accepted in the Japanese geological community.