Abstract
This paper describes the lithostratigraphy, microscopic characteristics, and conodont ages of Upper Triassic siliceous micrite from Kutajima Island, Kagoshima, southwest Japan. The siliceous micrite (ca. 34 m thick) comprises calcified radiolarians, thin-shelled bivalves, and calcispheres disseminated in a lime-mud matrix. Biostratigraphic data of conodonts show that the siliceous micrite accumulated in early Norian (Epigondolella quadrata Zone) through middle Norian (Epigondolella spiculata Zone to Epigondolella elongata Zone) with low sedimentation rates of 5.2 to 11.3 mm/kyr. The biotic constituents and lithologic characteristics of the siliceous micrite suggest the accumulation of deep-water oceanic basin. On the basis of lithologic characteristics and conodont ages, the siliceous micrite of Kutajima Island is compared with the siliceous micrite of the Sambosan accretionary complex, defined as a Late Jurassic to Early Cretaceous subduction-generated accretionary complex in southwest Japan.
