2013 Volume 64 Issue 3-4 Pages 85-112
The Nanjō Mountains located in the central region of Fukui Prefecture, Southwest Japan, are chiefly underlain by a sedimentary complex consisting of various rock-types such as basalt, limestone, chert, mudstone and sandstone. Among these rocks within the mountains, 27 chert outcrops were explored for their radiolarian content. In the studied Imajō district, the 14 rock samples from 10 localities yielded moderately- to poorly-preserved radiolarian remains as a result. Most of the samples contained Triassic to Middle Jurassic species, with Spumellaria and Entactinaria dominant among the Triassic faunas and Nassellaria dominant among the Jurassic faunas. The description and faunal analysis of these radiolarians revealed that the cherts in the Imajō district indicate a long range in age from the Olenekian? stage to the Bajocian stage.
