A Historical Review and Present Status of the Geological Studies of the Mino Terrane(Recent progress of geological researches on Paleozoic-Mesozoic System in Japan)

Abstract

Paleozoic to Mesozoic "geosynclinal" deposits, composed chiefly of sandstone, mudstone, siliceous shale, chert, limestone and greenstone, are widespread in the Mino terrane, central Japan. The history of geological studies of these deposits, especially from the micropaleontological standpoint is reviewed and some basic future problems are pointed out. Our knowledge on the geological age of "geosynclinal" deposits in the Mino terrane has accumulated with the progress of three kinds of biostratigraphical works: fusulinacean biostratigraphy mainly during the 1880's-1960's, conodont biostratigraphy prominently in the decade of the 1970's, and radiolarian biostratigraphy since the end of the 1970's. One of recent important findings is the existence of widespread Jurassic olistostrome complexes in this terrane; the olistostromes have varisized allochthonous blocks and sheets of Carboniferous to Triassic age. The timing and mode of emplacement of the olistostrome complexes are fundamental to the geological history of the Mino terrane.