Detrital Zircon U-Pb Ages of the Cretaceous Muju Basin: Implications for the Depositional Age and Provenance

Detrital zircon U-Pb dating was performed to determine the depositional age and provenance of sediments in the Cretaceous Muju Basin in Muju-gun, Jeollabuk-do. Six samples were collected from the Seolcheon Tuff (SCT), Bangyiri Formation (BYR), Gobang Member of the Gilwangri Formation (GWR-G), Seochang Member of the Gilwangri Formation (GWR-S), Bukchang Member of the Gilwangri Formation (GWR-B), and Jeogsangsan Formation (JSS). Based on the dating results, the sedimentary strata of the Muju Basin were deposited for approximately 105.6-90.4 Ma corresponding to the Albian to Turonian. The youngest single zircon ages of about 94.4 Ma and 89.6 Ma were confirmed in the samples from the Bangyiri Formation and the Gobang Member of the Gilwangri Formation, respectively, distributed in the western part of the Muju Basin. The relative and numerical ages previously estimated based on the lithostratigraphic correlation of the Gilwangri conglomerate need to be revisited in further research. The results also suggest that most of the sediments filling the Muju Basin were supplied from a limited area adjacent to the basin.