Middle and Late Permian radiolarians from the Nanjo Mountains, Fukui Prefecture, Southwest Japan

Abstract

    The Nanjo Mountains located in Fukui Prefecture, Southwest Japan are chiefly underlain by sedimentary complexes of various rock-types such as basalt, limestone, chert, mudstone and sandstone. A lot of reports on the occurrence of Mesozoic radiolarians mainly from mudstones in the mountains have been appeared in the last three decades, however litho-chronological information on Paleozoic rocks of the complexes is still not obtained enough because Paleozoic radiolarians have rarely been found. Through the present work, moderately- to poorly-preserved radiolarians recovered from tuffaceous and siliceous mudstones and cherts in the Nanjo Mountains are described and illustrated herein; they include genera Albaillella, Follicucullus, Pseudoalbaillella, Latentifistula, Pseudotormentus, Cauletella, Ishigaum, Raciditor, Srakaeosphaera and Stigmosphaerostylus, most of which are representatives of Middle and Late Permian periods. These radiolarian species are very important for giving an age constraint to the sedimentary complex in the Nanjo Mountains.