Published online May 1, 2023
Copyright © International Union of Geological Sciences.
Min-Kyu Oh1, Taejin Choi2, Seung-Bae Lee3, Jeong-Hyun Lee1,4*
1 Department of Astronomy, Space Science and Geology, Chungnam National University, Daejeon 34134, Republic of Korea
2 Department of Earth Science Education, Korea National University of Education, Cheongju 28173, Republic of Korea
3 Geological Museum, Korea Institute of Geoscience and Mineral Resources, Daejeon 34132, Republic of Korea
4 Department of Geological Sciences, Chungnam National University, Daejeon 34134, Republic of Korea
Correspondence to:*E-mail: firstname.lastname@example.org
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
The lithostratigraphic relationships among the basal Taebaek Group, including the Jangsan, Myeonsan, and Myobong formations, have been controversial until recently. It has long been assumed that the Jangsan and Myeonsan formations are lateral equivalents that are both conformably overlain by the Myobong Formation. However, recent studies have shown that the Jangsan is Precambrian in age and is unconformably overlain by the Cambrian succession, whereas the Myeonsan is a Cambrian unit. Accordingly, this study proposes a revised lithostratigraphic framework of the basal Taebaek Group. The Myeonsan Formation (Cambrian Age 3?) is defined here as a basal Cambrian succession consisting of a basal conglomerate and coarse-grained immature sandstone with detrital heavy minerals that unconformably overlies Precambrian basement. The Myobong Formation (~Cambrian Age 4–Wuliuan) is a fine-grained unit that conformably overlies the Myeonsan Formation. The Myobong is subdivided as follows: Seokpo Member of lenticular cross-laminated sandstone and siltstone; Daehyun Member of laterally continuous alternations of thin-bedded sandstone and siltstone with some carbonate-filled channels; Gurae Member of bioturbated sandstone. The Myeonsan Formation is comparable with lowermost Cambrian units in North China that formed during second-order transgression. Further sealevel rise led to the deposition of the Myobong Formation and its correlative units in North China.