Radiolarians from the Upper Cretaceous Himenoura Group, Nakakoshiki-jima Island, Kagoshima Prefecture, Japan.

Abstract

Upper Cretaceous radiolarians are commonly found in the E1 lithological unit of the Himenoura Group, Nakakoshiki-jima Island, Kagoshima Prefecture, Kyushu, Japan. This radiolarian assemblage is characterized by Amphipyndax stocki, Dictyomitra koslovae, D. multicostata, Pseudoaulofacus floresensis, and Stichomitra asymbatos, indicative of deposition between the Santonian and middle Campanian. The E1 lithological unit probably formed during the middle Campanian, as the underlying D lithological unit contains abundant middle Campanian inoceramids.