新潟県蒲原山地の足尾帯海洋性岩石から見出された放散虫・紡錘虫化石

概要

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Radiolarian and fusuline fossils were discovered respectively from chert and limestone blocks in the Ashio Terrane of the Kambara Massif, Southwest Japan. Radiolarians in gray bedded chert indicate an age of late Middle Permian (Capitanian) to early Late Permian (Wuchiapingian), and those in black massive chert indicate a latest Permian (Changhsingian) age. This is the first report of Late Permian oceanic rocks in the Kambara Massif. Fusulines in a piece of limestone float indicate a latest Carboniferous (Kasimovian and late Gzhelian) age. This limestone is probably the same as that reported in a previous study, broadly inferred to be Late Carboniferous to Early Permian in age. Therefore, the age of the limestone is now well constrained. These fossil data are important in reconstructing the oceanic plate stratigraphy of the Ashio Terrane of the Kambara Massif.
日本地質学会の論文