Radiolarians as tracers for provenance of gravels in Lower Cretaceous molasse (Outer Zone of SW Japan)

This paper discusses the results and the recent status of the study by radiolarians as tracers for erosional events, especially for those of Jurassic and pre-Jurassic accretionary complexes in the Outer Zone of SW Japan. As a test case to clarify the provenance of radiolarian-bearing gravels in conglomerates, the author reviewed the work previously done to trace the source rocks within oceanic-plate stratigraphy successions from monomictic chert-pebble conglomerates of the Lower Cretaceous Ryoseki-Monobegawa group. The group is a molasse typical of paralic sedimentary facies in the Outer Zone of SW Japan.