A role of large-scale volcanism in global environmental changes

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1.A worldwide tephra catalog is compiled for the Quaternary large-scale explosive eruptions. It covers such volcanic regions as Japan, New Zealand, North America, Europe, East Africa, and Southeast Asia. This tephra database includes petrographic characters of tephra-forming minerals, dating results, stratigraphic position in the marine isotope stages, distribution, volume, etc. This must be useful for correlation and identification of tephra observed in remote areas as well as for understanding of a role of large-scale eruptions in controlling global climatic changes.2.Of several marked transition stages in climate recorded in marine isotope fluctuations, border stages 3/2 and 5a/4 are characterized by such large explosive volcanisms as Aira-Tn and Taupo-Kawakawa tephras, and Toba tephra, respectively. This coincidence strongly suggests that rapid cooling may have induced or accerelated from these climactic volcanisms.3.The last 200-years long volcanic signals are determined from ice core of Antarctica. In particular, the 1809 and 1815 signals are prominent. The latter is a product of the great Tambora eruption, but the source volcano of the former has not yet been determined, presumably in the southern hemisphere.4.A non-glacial varved chronology is applied for determining calendar age of large scale eruptions producing several marker tephras such as Kikai-Akahoya and Ulreung-Oki ashes.