Detrital zircon U–Pb age of sandstone within the Jurassic accretionary complex in the Omori area, northeastern Shimokita Peninsula, Northeast Japan.

Abstract

Jurassic accretionary complexes, which are basement rocks lying under the Neogene sediments, in the northeastern part of the Shimokita Peninsula of the Northeast Japan, are separately distributed in the Kuwahatayama, Katasakiyama and Omori areas from the north. Although latest Jurassic to earliest Cretaceous radiolarian ages have been reported from the mudstone in Cape Shiriya in the Kuwahatayama area, no geologic ages have been reported from the accretionary complexes in the Katasakiyama and Omori areas. The U–Pb ages of detrital zircon from sandstone in the Omori area were examined in this study. Consequently, 154.7 ± 1.5 Ma (1σ) was obtained as a weighted mean age of the youngest cluster. Therefore, it has been confirmed that the sandstone was deposited after Late Jurassic.