2019 Annual Meeting of Japan Association of Mineralogical Sciences (JAMS)
Sep 19 - Sep 23, 2019Kyushu University Ito Campus
2019 Annual Meeting of Japan Association of Mineralogical Sciences (JAMS)
Sep 19 - Sep 23, 2019Kyushu University Ito Campus
[S1P-03]Reexamination of the relationship between Sambe–Ukinuno and Sakate tephras based on refractive indices and chemistry of tephra components
*Seiji Maruyama1(1. KFT)
Keywords:
Sambe–Ukinuno tephra,Sakate tephra,refractive index,chemical composition,tephra fall area
The Sambe–Ukinuno (SUk) tephra from Sambe volcano is dividied into the lowermost Uk-pfa, Md-fl, and uppermost Uk-fa. The Sakate tephra beds have been associated with the Md-fl. The refractive index of the volcanic glass shards of the Md-fl were lower than that of the Uk-pfa, because of the difference of the FeO contents rather than the SiO2 contents. The Md-fl/Uk-fa (Sakate) widely distributes in the Chugoku and Kinki districts, whereas the Uk-pfa distributes in the southern Kinki and the eastern end of the Shikoku.