Multiple volcanic eruption episodes in the highlands of Mt. Halla (Hallasan), Jeju Island, Korea: 40Ar/39Ar ages of lava flows

A new timeline of volcanic activity on Jeju Island's Mt. Halla (Hallasan) reveals two distinct eruption phases spanning approximately 170,000 years, with the last major eruptions occurring between 20,000 and 14,000 years ago. Using ⁴⁰Ar/³⁹Ar dating on 20 lava samples, researchers identified reliable ages from plagioclase and alkali feldspar crystals, challenging previous stratigraphic interpretations. The youngest dated flows (17.7±2.7 ka and 16.2±3.9 ka) suggest the final eruptions originated from Hallasan's summit caldera, flowing eastward. This study underscores the need for revised stratigraphic frameworks and deeper investigations, including core drilling, to fully understand Jeju Island's volcanic history.

Koh, G. W., Park, J. B., Hong, S. S., Ko, I. J., & Kim, T. H. (2019). Multiple volcanic eruption episodes in the highlands of Mt. Halla (Hallasan), Jeju Island, Korea: 40Ar/39Ar ages of lava flows. Journal of the Geological Society of Korea, 55(1), 71–86. https://doi.org/10.14770/jgsk.2019.55.1.71