U-Pb ages of detrital zircons in Lower Cretaceous non-marine successions of the Gyeongsang Basin, Northeast Asia: Implications for sediment provenance

The Cretaceous Gyeongsang Basin is the largest non-marine Mesozoic sedimentary basin of the Korean Peninsula. The Lower Cretaceous successions of the Gyeongsang Basin are coevally correlated to those of the Cretaceous Gunsan Basin in the Yellow Sea which is located far to the west of the Gyeongsang Basin. This study presents U-Pb ages of detrital zircons to evaluate the sediment provenances of the Gyeongsang Basin. The detrital zircon ages clearly show the different distributions between the northern (Uiseong area) and southern (Jinju area) areas of the Gyeongsang Basin. The detrital zircons of the northern area have an age cluster in the Jurassic or Triassic, whereas the detrital zircons of the southern area show a wide range of ages from early Cretaceous to Neoarchean. In the Gunsan Basin, detrital zircons from a core also yield ages ranging from early Cretaceous to Neoarchean. The age distribution from the Gunsan Basin is similar to those of the southern Gyeongsang Basin, except for the absence of Jurassic detrital zircons. The petrographic modal analysis of sandstones in the Gyeongsang Basin suggests a mixed provenance. This study indicates that possible sediment provenances of the Gyeongsang Basin were shared with those of the Gunsan Basin. We suggest that the sediment provenance of the northern Gyeongsang Basin was adjacent basement highs, whereas sediments to the southern Gyeongsang Basin were probably derived from relatively distant source areas that possibly were located in the vicinity of the Gunsan Basin during the early Cretaceous (ca. 113 Ma).