Guraigol (Hantangang River UNESCO Global Geopark)

Guraigol is a compound word of 'gul' (cave) and 'awi' (rock), also called Gulbawi. It is named so because the canyon resembles a cave in summer when the vegetation is lush. Guraigol is a small basalt canyon formed in a tributary of the Hantangang River, and it is one of the places where three lava flows with different cooling processes can be well observed.<br /><br />The uppermost part observed has a thickness of about 5m, does not have developed columnar joints, and is characterized by breaking into massive blocks. Additionally, a weak clinker is developed in the lower part. In the middle and lower parts, cylindrical separation structures are well observed, indicating relatively slow cooling. It is divided into upper, middle, and lower parts according to the presence and characteristics of columnar joints.<br /><br />In the lower and middle parts, columnar joints are well developed, with the lower part being relatively larger and more irregular than the middle part. In the middle part, columnar joints with a diameter of 20-30cm are regularly developed. In the uppermost part of the upper section, 2-3 layers of lava crust are observed, and columnar joints are developed below, but the diameter is larger compared to the columnar joints in the middle part.<br /><br /><Source: Hantangang River Geopark>