Ocean plate stratigraphy (OPS) within an ancient accretionary complex provides important information for understanding the history of an oceanic plate from its origin at a mid‐ocean ridge to its subduction at a trench. Here, we report a recently discovered chert–clastic sequence (CCS) that comprises a continuous succession from pelagic sediments to terrigenous clastics and which constitutes part of the OPS in the Akataki Complex within the Cretaceous Shimanto Accretionary Complex on the central Kii Peninsula, SW Japan. As well as describing this sequence, we present U–Pb ages of detrital zircons from terrigenous clastic rocks in the CCS, results for which show that the youngest single grain and youngest cluster ages belong to the Santonian–Campanian and are younger than the radiolarian age from the underlying pelagic sedimentary rock (late Albian–Cenomanian). Thus, the CCS records the movement history of the oceanic plate from pelagic sedimentation (until the late Albian–Cenomanian) to a terrigenous sediment supply (Santonian–Campanian).

中文翻译：

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日本西南部吉伊半岛中部白垩纪四万十增生复合体中的石碎屑序列

古代增生复合体内的海床地层学（OPS）为了解海床从中洋脊的起源到海沟的俯冲提供了重要的信息。在这里，我们报道了最近发现的石-碎屑岩层序（CCS），其包括从上层沉积物到陆源碎屑岩的连续演替，并且构成了日本西南部纪伊半岛中部白垩纪四万十增生复合群中的Akataki群中的OPS的一部分。 。除了描述此序列外，我们还介绍了CCS中陆源碎屑岩碎屑锆石的U–Pb年龄，结果表明，最年轻的单粒和最年轻的团簇年龄属于桑托尼亚－坎帕尼时代，并且比潜在的中上层沉积岩（晚阿尔比－西诺曼尼亚）的放射虫年龄小。因此，CCS记录了洋中板块从上层沉积（直到晚期的阿比安-西诺马尼亚）到陆源沉积物供应（桑托尼-坎帕尼亚）的运动历史。