Influence of Aira-Tn Ash (AT) eruption on ecosystem

Abstract

We discuss the effects of Aira-Tn Ash (AT) eruption on ecosystem, based on fossil pollen and diatom assemblages obtained from central and northern Honshu in Japan. This eruption occurred during the Last Glacial Maximum (21 000 - 22 000 or 24 000 years ago) in the Aira Caldera in southern Kyushu. The fossil pollen accumulation rate and pollen assemblages from AT deposits show that the ash fall occurred in the spring. We conclude that the AT fall occurred during, and accelerated, the last stage of climate change to a colder phase, and of attendant vegetation change to coniferous forests, that began about 30 000 years ago. the AT fall also caused a rise in level and a change in pH from acid to alkaline of the sedimentary environment water. -from English summary