Detrital zircon U–Pb ages of the Miocene clastic sedimentary succession in the Shidara Basin, central Japan: Implications for provenance changes and timing of collision between the Izu–Ogasawara and Honshu arcs

Abstract

• Zircon U–Pb dating revealed provenance change in the middle of Miocene succession. • Deposition of Miocene strata was associated with the initial collision of two arcs. • Collision between the two arcs was initiated at around 17.4 ± 0.4 Ma. Collision of the Izu–Ogasawara and Honshu arcs occurred during the Miocene. The Miocene Hokusetsu Subgroup in the western part of the Izu collision zone is considered to be a key formation that might record the timing of the initial collision. To clarify the timing, we conducted provenance analysis based on detrital zircon U–Pb ages of the Hokusetsu Subgroup. Zircon ages show a Late Cretaceous peak in the strata below the Umedaira Sandstone Member and a peak around 100 Ma in the lower Umedaira Sandstone Member. Furthermore, the proportions of Jurassic to Proterozoic ages increase in the upper part of the sandstone member and the overlying horizons. The zircon ages and the petrographical characteristics of detritus suggest that the formations below the lower Umedaira Sandstone Member were derived from the Ryoke Plutonic Rocks, but the formations above the upper Umedaira Sandstone Member were derived from a Jurassic accretionary complex. Deposition of the Umedaira Sandstone Member suggests uplift of the provenance areas, which are inferred to have been the 100 Ma Ryoke Plutonic Rocks to the northeast and east of the Shidara Basin and Jurassic accretionary complexes farther to the northeast and east. The provenance change during deposition of the Umedaira Sandstone Member was caused by collision of the Izu–Ogasawara and Honshu arcs. Therefore, the collision is considered to have begun around 17.4 ±0.7 Ma constrained by depositional age of the Umedaira Sandstone Member.