Morishita, TomoakiArai, ShojiGreen, David2015-12-132015-12-130022-3530http://hdl.handle.net/1885/94085Unusually alumina-poor orthopyroxene is found in a spinel peridolite from the Horoman Peridotite Complex, Japan. Al2O3, Cr2O3 and CaO contents in the low-Al orthopyroxene (named Low-Al OPX hereafter) are <0·25 wt%, <0·04 wt% and <0·3 wt%, respectively,Keywords: chemical composition; mantle; metasomatism; orthopyroxene; peridotite; petrography; Japan Horoman Peridotite Complex; Low-Al orthopyroxene; Mantle wedge; Metasomatism20032015-12-12