2022 Annual Meeting of Japan Association of Mineralogical Sciences (JAMS)

Presentation information

Oral presentation

R7: Petrology, Mineralogy and Economic geology (Joint Session with Society of Resource Geology)

Sat. Sep 17, 2022 9:30 AM - 12:30 PM B253 (Adv. Edu. Res. Bldg. E-2F)

Chairperson: Norikatsu Akizawa(The Univ. Tokyo), Taakuya Echigo(Akita Univ.)

11:30 AM - 11:45 AM

[R7-08] Formation of anorthite megacrysts from their inclusions in the Mt. Kayo, Oguro lava in Akita Prefecture

*Takeyoshi Nishiwaki1, Takuya Echigo1 (1. Akita Univ. Sci)

Keywords:Anorthite, Mt Kayo, EPMA, Chemical zoning, Crystal growth

Anorthite megacrysts with a maximum length of about 3 cm occur in the Oguro lava of Mt.Kayo in Senboku City Akita Prefecture. In this study, examined mineralogical characteristics of the anorthite metacysts from Mt.Kayo and the formation of anorthite megacrysts.
The inclusion of pyroxene in some of the mafic crystals suggests that the pyroxene crystallized before the anothite under relatively high pressure, and then the anothite crystallized under conditions outside the pyroxene stability conditions, as suggested by the numerical experiments by Bindeman & Bailey (1999).