S1: Earth materials science in igneous processes (Special Session)

[S1-01] Reconstruction of lithosphere-asthenosphere boundary in arc settings by geobarometry of spinel peridotites from Ichinomegata, NE Japan

「発表賞エントリー」

*Yuto Sato¹, Kazuhito Ozawa¹ (1. Univ. Tokyo Sci.)

Keywords:lithosphere-asthenosphere boundary, geobarometry, spinel peridotite xenolith, wet solidus

This study reports the reconstruction of structures and formation conditions of the lithosphere-asthenosphere boundary zone (LABZ), which is based on the estimation of depths for the 9 spinel peridotite xenoliths from Ichinomegata. The LABZ beneath Ichinomegata was present at 41-55 km depths and was substantiated by the development of deformation microstructure during a heating event just before the xenolith derivation which caused partial melting. The concurrence of the deformation and the partial melting at LABZ indicates that LABZ in arc settings is controlled by wet solidus.