Research history of the Seba region in the Sambagawa metamorphic belt, central Shikoku, with special focus on its field-geological aspect.

Abstract

Abstract:In the Seba area of the Sambagawa belt it was previously proposed that eclogitic basic schists found in the area adjacent to a metagabbro body formed by solid-state contact metamorphism as a result of tectonic emplacement of the metagabbro. This explanation has been reexamined through later studies, which include discovery of a number of eclogitic basic schists (or their constituting mineral, omphacite) distant from the metagabbro and recognition of relationship between multiple deformation stages and growth of omphacite. The results indicate formation of all the eclogitic basic schists in the Seba area can be attributed to a single regional eclogite-facies metamorphism. This research history gives the following implications to field studies for high-grade metamorphic regions: 1) recognition of key metamorphic minerals and of its map distribution should be done with great care; and 2) multiple deformation stages and their associated structures should be classified in relationship to growth timing of metamorphic minerals.