紀伊半島中央部大峯山地の放散虫化石群集

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Geology of the central part of Kii peninsula consists of the Mesozoic Hidakagawa and the Paleozoic Sanjogadake Groups with thrust up contact. In this paper we report Cretaceous radiolarian assemblages from the Tsuzurao Formation of the Hidakagawa Group and geological age assignments based on their radiolarian occurrence. Radiolarian fossils from the formation suggest its geologic age ranging from middle Albian to middle Turonian. These radiolarian assemblages correspond to the Dictyomirta duodecimcostata-Dictyomitra pseudomacrophora assemblages from the northern part of the present area previously reported by YAMATO-0HMINE RESEACH GROUP (1981). On the other hand, some blocks of the Tsuzurao Formation occurred early Valanginian-early Coniasian radiolarian assemblages and they were considered geologically as olistoliths taken into the Cenomanian strata. Cenomanian radiolarian assemblages are correlated to the Holocryptocanium barbui-Holocryptocanium geyserensis assemblages in the Shimanto belt of Shikoku (NAKASEKO et al., 1979).
奈良教育大学の論文