Western End of Late Cretaceous Fore-arc Basin and Provenance in SW Japan: Detrital Zircon U–Pb Dating of Upper Cretaceous–Paleogene Sandstones in Nagasaki-Nishisonogi Peninsula, Western Kyushu

Uranium–Pb ages of detrital zircons taken from seven sandstone samples collected at what were previously called “Paleogene strata” in the Nagasaki and Nishisonogi Peninsula, northwestern Kyushu, SW Japan are measured. Depositional three sandstones peninsula revealed to be e Campanian–Maastrichtian (Late Cretaceous) or younger. two Terashima Island off west coast Peninsula likewise dated as Campanian By contrast, western confirmed Ypresian–Lutetian (Eocene) These new concordant with sporadically reported mollusk fossils, basically supporting previous stratigraphic scheme, except for a distinct Upper Cretaceous strata Mitsuze Formation. The age spectra four share same pattern; i.e., ranging Aptian–Campanian peak around Cenomanian. Maastrichtian has grains Albian–Maastrichtian Turonian, which is slightly younger than that sandstones. Judging dominance Middle zircon grains, main provenances probably Ryoke/San-yo San-in granite belts Japan, where Late felsic igneous rocks extensively exposed. almost identical those Himenoura Mifune groups central Izumi Group Shikoku/western Kii peninsula. All these units deposited unconformably over Ryoke granitoids. Within elongated arc-trench system extending 1,300 km Kyushu northern Kanto, Formation Nagasaki-Nishionogi mark known end large-scale fore-arc basin Japan.