著者

岡田 里奈 近藤 美左紀 梅田 浩司 古澤 明 天野 格

出版者

特定非営利活動法人 日本火山学会

雑誌

火山 (ISSN:04534360)

巻号頁・発行日

vol.68, no.2, pp.91-98, 2023-06-30 (Released:2023-07-27)

参考文献数

25

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The Zenikame-Menagawa tephra (Z-M) has been reported from distal terrestrial settings in the southern Hokkaido, with those erupted from Zenikame volcano, and provides an important stratigraphic marker for paleoenvironmental reconstructions of marine isotope stage 3 (MIS 3). We use both major element (EPMA) and trace element (LA-ICP-MS) analyses on proximal and distal Z-M shards to make the correlations to explosive eruptive events. Proximal stratigraphic succession is divided into deposits of two main eruptive phases with pyroclastic fall (Z-Mpfa) followed by pyroclastic flow (Z-Mpfl). The Z-Mpfl and Z-Mpfl deposits are geochemically distinct and thus their origins can be different. Considering geochemical characteristics of glass shards, the distal Z-M in the Tokachi district, located about 200 km west of the source volcano, can be identified as ash fall deposits associated with the Z-Mpfl eruption.