HARA Hidetoshi (2020) Detrital zircon U–Pb age estimated from calcareous sandstone of the Cretaceous Takaoka Formation in eastern margin of the Kanto Mountains

Abstract

U–Pb dating of detrital zircons were analyzed from a calcareous sandstone of the Lower Cretaceous Takaoka Formation, distributed in the eastern margin of the Kanto Mountains. The youngest single grain age and the youngest cluster age were estimated to be 109.7 ± 0.8 Ma and 110.0 ± 1.0Ma, respectively. Both ages represent the early Albian, suggesting that the Takaoka Formation deposited after the early Albian. In addition, the calcareous sandstone of the Takaoka Formation is characterized by abundant content of Permian to Triassic zircons (276–240 Ma). Based on detrital zircon U–Pb age and sandstone lithology, the Permian to Triassic granitic rocks and the Chichibu accretionary complex were widely distributed in provenance of the Takaoka Formation. The Takaoka Formation corresponds to the Sanyama Formation in the Sanchu Cretaceous System. However, both formations present different peak spectra of detrital zircon U–Pb ages, and are characterized by different provenances.