Dataset for "Characteristics of Columnar Joints distributed on the Southwestern Coast of the Korean Peninsula"

Abstract: Columnar joints on the southwestern coast of the Korean Peninsula develop in various sizes and shapes depending on topographical characteristics. This study selected Buan, Shinan, Goheung, Suncheon, and Yeosu, where columnar joints are developing on a large scale, among the coastal areas in the southwestern part of the Korean Peninsula as the study area. Jeokbyeokgang has columnar joints developed from rhyolite formed by the eruption and intruded rhyolite, and a vertical colonnade is formed. In Ji-do, vertical colonnades develop, in Jeung-do, dome-shaped structures, and Manjae-do, columnar joints develop in intruded rocks along with vertical colonnades. In Goheung, fan-shaped columnar joints are developed, and in Suncheon, columnar joints with large-scale colonnades that are inclined in a certain direction are developed. The columnar joints of Yeosu show a unique structure compared to columnar joints developed in the Hyangilam. It appears that small columnar joints develop inside large columnar joints. Thick volcanic ash deposition is postulated to have initiated the formation of primary columnar joints during the subsequent cooling process. It is inferred that further cooling processes led to the development of secondary, small-scale columnar joints within the interior. In general, the higher the SiO2 content, the length of the polygon side of the colonnade tends to increase. However, the length of the polygon side of the colonnade appears differently in each region. This indicates that topographic factors played a more dominant role than rock chemical composition in the formation of columnar joints in the study area.