Details

Autor(en) / Beteiligte

• Watanabe, Yasushi

Titel

40Ar-39Ar Spectra of Alunite from Phreatic Craters in the Muine Volcano, Hokkaido, Japan

Ist Teil von

• Resource geology, 2003-09, Vol.53 (3), p.221-226

Ort / Verlag

Oxford, UK: Blackwell Publishing Ltd

Erscheinungsjahr

2003

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• . 40Ar‐39Ar analyses of two alunite samples from phreatic craters in the Pliocene Muine volcano in southwest Hokkaido, Japan, were carried out. The alunite with 17.4 permil δ34SV_CDT value in hydrothermal breccia from the Nagaoyama crater and that with 14.3 permil δ34SV_CDT value in silicified andesite from the Konuma crater give total fusion ages of 1.40 ± 0.04 Ma (la uncertainty) and 1.24 ± 0.08 Ma, respectively. However, the spectra of these samples indicate they have been effected by thermal overprinting and/or the existence of excess argon. These preliminary 40Ar‐39A analyses suggest that the alunite underwent multiple hydrothermal activity by magmatic gas and vapor subsequent to the main hydrothermal activity.