東北日本弧, 那須火山群の形成史 [in Japanese] Evolutionary history of the Nasu volcano group, Northeast Japan arc [in Japanese]
Access this Article
Search this Article
The Nasu volcano group is composed of six volcanic edifices, Kasshiasahidake, Sanbon-yaridake, Asahidake, Minamigassan, Futamatayama, and Chausudake, located in the volcanic front of the Northeast Japan arc.<br> Kasshiasahidake (ca. 0.54-0.42 Ma), Sanbon-yaridake (ca. 0.36-0.27 Ma), Minamigassan (ca. 0.21-0.03 Ma) have similar geological sequences. Alternation of thin basaltic andesite lava flows and associated pyroclastics developed in the lower part, whereas thick andesitic or dacitic lava flows and minor pyroclastic flows developed in the upper part. Between these two stages, caldera collapse sometimes occurred. On the other hand, Asahidake (ca. 0.21-0.06 Ma), Futamatayama (ca. 0.14 Ma), and Chausudake(ca. 0.04-0 Ma) are composed of andesitic lavas, lava domes, and pyroclastic flows, lacking thin basaltic andesite sequences. From evolutionary historical point of view, Kasshiasahidake, Sanbon-yaridake, and Minamigassan (including Asahidake and Chausudake edifices) edifices construct individual stratovolcanoes, which have similar evolutionary histories. Futamatayama is distinct from these.<br> Volume and eruption duration of the three stratovolcanoes are as follows; ca. 200 k.y., 16.2 km<sup>3</sup> for Kasshiasahidake, ca. 150 k.y., 7.2 km<sup>3</sup> for Sanbon-yaridake, ca. 200 k.y., 17.8 km<sup>3</sup> for Minamigassan (including Asahidake and Chausudake). These volumes and eruption rates are less than those of large stratovolcanoes (Akagi, Haruna, Hakone volcanoes etc.) in near the triple junction of plate boundary, but are comparable to those of small stratovolcanoes (Quaternary volcanoes in Shin-etsu Highland).
- Journal of Mineralogical and Petrological Sciences
Journal of Mineralogical and Petrological Sciences 90(6), 195-214, 1995-06-05
Japan Association of Mineralogical Sciences