2026-03-09T02:52:48Z https://juen.repo.nii.ac.jp/oai

oai:juen.repo.nii.ac.jp:00004771 2024-03-11T05:03:39Z 993:994:1005

Note on rock-forming minerals in the Joetsu district, Niigata Prefecture,Japan. (14) Hornblende in the volcanic rocks from the Yoneyama and Myoko volcanos Oba, Takanobu ca-amphibole hornblende gabbro magnesiohornblende Myoko volcano group pargasite Yoneyama The volcanic rocks of the Myoko in Quaternary and the Yoneyama in late Pleiocene are distribed in the Nishikubiki region, Niigata Prefecture. In the Myoko volcanoes, pyroxene and hornblende andesites are common, and basalt is accompanied in subordinate amount. The majority of volcanic rocks from the Yoneyama are two pyroxene andesite, they are the rock types as follows: olivine-clinopyroxene-orthopyroxene basalt with or without hornblende, clinopyroxene- orthopyroxene andesite and hornblende clinopyroxene-orthopyroxene andesite. Hornblende gabbro occurs in these volcanic rocks. The amphiboles from the Yoneyama are magnesiohornblende to pargasite, on the other hand, the amphiboles from the Myoko except for the Maruyama lava are magnesiohornblende. Amphiboles in the Maruyama lava are pargasite. Amphiboles in the volcanic rocks from both the Myoko and Yoneyama in this study are near the tremolite-pargasite join in the field of hornblende from gabbroic inclusions from the Yoneyama. 上越教育大学 2000-03 eng departmental bulletin paper VoR http://hdl.handle.net/10513/322 https://juen.repo.nii.ac.jp/records/4771 AN10284863 0915-8162 上越教育大学研究紀要 19 2 483 491 https://juen.repo.nii.ac.jp/record/4771/files/kiyo19_2-07.pdf application/pdf 538.7 kB 2015-06-17