Characterization of the Oman ophiolite peridotites using the relationship between clinopyroxene Nd isotopic ratios and spinel compositions

抄録

Clinopyroxene (Cpx)-rich peridotites have been observed at the base of mantle section from northern to southern massifs in the Oman ophiolite. We present Nd isotopic ratios of Cpx grains separated from the Cpx-rich peridotites of the central Sarami massif and compared them with published Nd isotopic ratios of Cpx grains from the northern Fizh and the southern Wadi Tayin Cpx-rich peridotites. The Nd isotopic data combined with spinel Cr# suggest that fertile Cpx-rich peridotites (spinel Cr# <0.3) from the northern and the central massifs preserved a simple melt extraction event, whereas relatively refractory Cpx-rich peridotite (spinel Cr# = 0.33) from the southern massif and harzburgite (spinel Cr# = 0.55) from the northern Hilti massif recorded a further melt extraction event with an influx of a mid ocean ridge basalt like melt.