Permian radiolarians from Paleozoic strata in the Tanto area, southeastern part of Toyooka City, Hyogo Prefecture, Southwest Japan

Abstract

Paleozoic strata are known to be present in the Tanto area of Toyooka City, in Hyogo Prefecture, but these sediments are poorly documented. This study indicates that these sediments are dominated by mudstones and felsic tuffs with conglomerates and red cherts that are intercalated with the felsic tuffs. Mudstones in the study area contain a radiolarian fossil assemblage that includes Pseudoalbaillella aff. longicornis Ishiga and Imoto, and this assemblage is indicative of a latest Early Permian to middle Middle Permian age of deposition. These lithological and geochronological features suggest that Paleozoic strata in the study area correlate with the Shimomidani Formation of the Akiyoshi or “Shidaka” terranes, consistent with previous research.