Geologic characteristics of Jeju Samdasoo watershed in Jeju Island, Korea (II): Subsurface geology and volcanic activities

Research reveals that the subsurface geology of Jeju Island's Samdasoo watershed, Korea, spans approximately 500,000 years of volcanic activity, with lava flows and non-volcanic sediment layers forming its foundation. Analysis of eight drill cores identified 19 distinct geological units, including alkaline basalt to trachybasalt compositions, with the lowest layers showing more evolved tholeiitic basalt characteristics. Ar-Ar dating pinpointed three major volcanic phases: Phase I (466±9–444±8 ka), Phase II (367.5±7.9–212.8±4.0 ka), and Phase III (200±13–26.9±3.3 ka). The study integrated core analysis, petrography, geochemistry, and dating to reconstruct the region's volcanic history, providing critical insights for understanding Jeju Island's geological evolution.

Koh, G. W., Park, J. B., Kim, T. H., Koh, H. J., Moon, D. C., Mun, S. H., & Han, H. J. (2021). Geologic characteristics of Jeju Samdasoo watershed in Jeju Island, Korea (II): Subsurface geology and volcanic activities. Journal of the Geological Society of Korea, 57(3), 307–328. https://doi.org/10.14770/jgsk.2021.57.3.307