New mantle xenolith locality: the Bankawa peridotite xenolith suite (southern Osaka, SW Japan)

Abstract

A new locality of mantle xenoliths (lherzolites) was found in southern Osaka, SW Japan (Bankawa area). Their host is a 7.5 Ma alkaline basalt dike.  Olivine shows Fo₉₁ in composition, and the Cr# of spinel is 0.2 to 0.3 in the phlogopite-free lherzolite. Olivine shows slighly lower Fo contens (91~88) in the phlogopite-bearing ones. The former are similar to abussal lherzolite and the latter were metasomatized from the former by an intra-plate alkaline magma.