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.摘要：朝鲜半岛西南沿海的柱状节理（columnar joints）会依据地形特征呈现出多样的尺寸与形态。本研究选取朝鲜半岛西南沿海区域中，柱状节理大规模发育的扶安（Buan）、新安（Shinan）、高兴（Goheung）、顺天（Suncheon）与丽水（Yeosu）作为研究区域。绝壁江（Jeokbyeokgang）的柱状节理发育于火山喷发形成的流纹岩（rhyolite）及侵入流纹岩中，形成了垂直柱状节理群。在智岛（Ji-do），垂直柱状节理群发育；在曾岛（Jeung-do），区域内发育穹状构造；而在蔓菁岛（Manjae-do），侵入岩中兼具柱状节理与垂直柱状节理群发育。高兴地区发育扇形柱状节理，顺天地区则发育具有大规模节理群、且沿特定方向倾斜的柱状节理。与香一庵（Hyangilam）发育的柱状节理相比，丽水的柱状节理呈现出独特构造：大型柱状节理内部发育小型柱状节理。研究推测，厚层火山灰沉积为后续冷却过程中原生柱状节理的形成提供了起始条件；进一步的冷却作用则促使次级小型柱状节理在岩体内部发育。总体而言，二氧化硅（SiO₂）含量越高，柱状节理群的多边形边长往往越长，但不同区域的节理群多边形边长仍存在差异。这表明，在本研究区域的柱状节理形成过程中，地形因素相较于岩石化学成分占据了更为主导的地位。