Japan Geoscience Union Meeting 2019

Presentation information

[J] Oral

S (Solid Earth Sciences ) » S-MP Mineralogy & Petrology

[S-MP32] Deformed rocks, Metamorphic rocks and Tectonics

Wed. May 29, 2019 10:45 AM - 12:15 PM A08 (TOKYO BAY MAKUHARI HALL)

convener:Yumiko Harigane(Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST)), Yoshihiro Nakamura(Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology), Chairperson:Tomoki Taguchi(京都大学 大学院理学研究科), Kenta Yoshida(JAMSTEC)

11:00 AM - 11:15 AM

[SMP32-08] FeAlO3 phase at ultrahigh-temperature metamorphic conditions: Evidences from the sillimanite—Fe2O3 and sillimanite—Fe3O4 systems at 9 kbar and 1050 ℃

*Toshisuke Kawasaki1, Tatsuro Adachi2, Hiroaki Ohfuji1, Yasuhito Osanai2 (1.Ehime University, 2.Kyushu University)

Keywords:FeAlO3 phase, sillimanite, corundum, spinel, ultrahigh-temperature granulies

Two high pressure experiments at 9 kbar and 1050 ℃ under moisture condition reveal FeAlO3 phase is stable under ultrahigh-temperature metamorphic conditions. FeAlO3 and corundum newly crystallised accompanying SiO2-rich melt and vapour among sillimanite crystals from the mixture of Rundvågshetta sillimanite and reagent-grade Fe2O3 (weight ratio of 95:5) within Pt capsule. We found no hematite in the charge. In contrast, we found FeAlO3 phase, SiO2-rich melt and vapour among sillimanite from the mixture of Rundvågshetta sillimanite and reagent-grade Fe3O4 at (weight ratio of 86:14) within AuPd capsule. We found a domain composed by FeAlO3, corundum, magnetite—hercynite spinel and ulvöspinel at the bottom part of the charge. The domain was contact with melt among sillimanite. The present results suggest the possibility that FeAlO3 phase would be an index mineral of ultrahigh-temperature metamorphism for the partially melted Fe—Al-rich granulites under hydrous and oxidised environments.