Paleozoic sedimentation and tectonics in Korea: A review

Abstract

Abstract The geological history of the Korean Paleozoic is recorded in lower and upper Paleozoic strata, mostly distributed in two relatively large sedimentary basins, the Taebaeksan and Pyeongnam basins. The lower Paleozoic sedimentary rocks are exclusively of marine origin, dominated by shallow platform carbonate rocks with minor interbedded siliciclastic rocks. The development of the lower Paleozoic sequence was mostly controlled by eustatic changes, having cyclic sedimentation of various temporal scales. During the early Paleozoic the Korean Peninsula was located in a low‐latitude tropical region and experienced frequent storm activities. The upper Paleozoic sequence comprises paralic to non‐marine rocks with minor limestone intercalations in the lower part of the sequence. Upsection changes in sandstone composition and mudrock geochemistry of the upper Paleozoic Pyeongan Supergroup in the Samcheok coalfield indicate that sediments may have been derived from the continued uplift and unroofing of a collisional orogen source. There exists a great unconformity between the lower and upper Paleozoic strata, which spans the geological time from the Late Ordovician to Early Carboniferous. The unconformity period is conventionally thought to be of non‐deposition, but a recent study suggests that it is characterized by continuous sedimentation and significant removal (>1 km thick) of sediments by erosion. No Paleozoic tectonic history has been addressed so far, and thus it needs further study to elucidate geological events during the middle–late Paleozoic in the Korean Peninsula. Tectonostratigraphic correlation of the Korean Peninsula with neighboring Chinese blocks has been a hot issue for a long time. Although the eastward extension of the Chinese collision belt has been recently suggested to be the Imjingang belt located in the middle of the peninsula, further studies are needed to test this hypothesis because results of recent paleontological, sedimentological and stratigraphic studies on Paleozoic sediments are not in agreement with this possibility.