Paleogeographic evolution of the western Taebaeksan Basin, Korea: constraints from provenance of late Carboniferous sediments

A distinctive unconformity between Cambro-Ordovician and Permo-Carboniferous strata in North China and the Taebaeksan Basin (TB) in Korea has been regarded as key evidence supporting their tectonic affinity (the ‘Sino-Korean Block’). However, controversy continues over the palaeogeographic position of the western part of the TB prior to the North and South China collision. To resolve this issue, we focus on the basal units of the upper Palaeozoic sequence overlying the Cambro-Ordovician strata. Results show that these late Carboniferous sediments, the Gapsan and Yobong formations in the western TB and the Manhang Formation in the eastern TB are all highly similar in composition, suggesting a common provenance: sandstones mostly consist of quartz and (meta)sedimentary rock fragments and are virtually devoid of feldspar; mudrocks are extremely depleted in CaO and Na₂O, while elemental ratios of immobile trace elements including rare earths are comparable to the recycled upper continental crust; detrital zircon ages are highly concentrated at 1.8–1.9 Ga and 310–340 Ma, whereas Meso- to Neoproterozoic ages are scarce. Coupled with the clear similarities in lithology, the collected data are in favour of the palaeogeographic views that the western and eastern TB were contiguous by the late Carboniferous.