Host: Japan Association of Mineralogical Sciences
Ultrahigh-pressure chromitites from Ray-Iz ophiolite, Polar Urals, and Luobusa ophiolite, Tibet, are examined and, to constrain the origin of ultrahigh-pressure chromitite. Ray-Iz chromitites are mostly concordant to the foliation of the surrounding meta harzburgite. Chromitites show disseminated, massive and nodular texture. Spinels from chromitite and surrounding dunite show high Cr# (0.75-0.85) and low TiO content (0.1 to 0.2 wt%). Chromian spinel grains of Ray-Iz chromitite contain thin lamellae of clinopyroxene and rutile. Spinels do not contain orbicular inclusions of primary hydrous minerals, such as pargasite and Na phlogopite. These characteristics of Ray-Iz chromitites are similar to that of Luobusa ophiolite, Tibet.
