Shallow-marine records of pyroclastic surges and fallouts over water in Jeju Island, Korea, and their stratigraphic implications

A unique shallow-marine volcaniclastic deposit on Jeju Island, Korea, reveals how pyroclastic surges and fallouts transported materials to the water surface before settling under tidal processes. This deposit, formed at an exceptionally high sedimentation rate—millions of times faster than adjacent strata—captures 'fair-weather' processes with unprecedented resolution. The study challenges conventional views by demonstrating that volcanic deposits, often seen as products of catastrophic events, can more faithfully record ordinary environmental conditions than nonvolcanic sediments. Researchers analyzed the deposit's characteristics, including mud flasers and drapes, to infer its rapid accumulation during tidal cycles.

Sohn, Y. K., & Yoon, S.-H. (2010). Shallow-marine records of pyroclastic surges and fallouts over water in Jeju Island, Korea, and their stratigraphic implications. Geology, 38(8), 763–766. https://doi.org/10.1130/g30952.1