|Budget Amount *help
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1996: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1995: ¥1,500,000 (Direct Cost: ¥1,500,000)
To clarify the origin and paleogeographic transition of the South Kitakami Paleoland, the Early-Middle Paleozoic geotectonic history and Paleozoic biogeography of the South Kitakami Belt were studied.
The South Kitakami Belt is a part of the continent, South Kitakami Paleoland, having pre-Silurian (Caledonian) basement rocks : the high P/T type Matsugadaira-Motai Metamorphic Rocks, which were metamorphosed at about 500 Ma, Ordovician Hayachine Complex, late Ordovician (440 Ma) Hikami Granites and Shoboji Diorites. The basements are covered by the unmetamorphosed shallow marine sedimentary rocks ranging fron Silurian to Lower Cretaceous. Based on the Paleozoic geotectonic histort and paleobiogeography, the basements are considered to had been formed, during Cambrian to Ordovician time, in an accretionary prism situated at the northern margin of the Gondwanaland. It might be an extension of the South China Accretionary Fold Belt or Adelaide Fold Belt of eastern Australia.
The South Kitakami Paleoland, together with the South China, was separated from the southward migrating Australia (Gondwanaland) during the Carboniferous. Permian and Triassic ammonoid paleobiogeographic data implies that the South Kitakami Pleoland was located in the equatorial Tethys and closely situated with South China and Southern Primorye during Middle to Late Permian time. North China differs from South China and South Kitakami in that the Lower Permian strata of the northern margin of the North China yield Boreal ammonoids and no Middle Permian paraceltitid have been reported from there. The close geographic relationships among South China, Southern Primorye and South Kitakami, especially between the latter two had persisted at least until Middle Triassic.