Records of palaeo-sea level and eruption duration in a coastal tuff ring, Jeju Island, Korea

초록

Phreatomagmatic volcanoes and their sedimentary products can preserve high-resolution records of earth surface processes because of their high deposition rate. Songaksan, Jeju Island, Korea, is a phreatomagmatic volcano, which erupted c. 3.7 ka BP in a coastal setting. Its tuff ring preserves a record of intertidal to supratidal facies transition in the basal part, which reveals the position of palaeo-high-tide level for at least 13 high-tide events, and a record of a storm-surge event in the middle part of the tuff ring, which lasted approximately three tidal cycles. Based on these features, the phreatomagmatic eruption of Songaksan is estimated to have taken place over a month. The sea level at the time was almost identical to that at present. This study shows that coastal phreatomagmatic volcanoes can preserve high-resolution records of eruption duration and palaeo-sea level, and can provide accurately levelled and dated data points to the Quaternary sea-level curve.

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