Vice professor TANG Yanjie and his team study element and Li–Sr–Nd isotopic data for minerals in peridotite xenoliths from the Hannuoba, Fanshi and Hebi localities in the Trans-North China Orogen of the North China Craton. They find the Li-Sr-Nd isotopic disequilibrium between minerals of peridotite xenoliths.

Their results suggest that a relatively recent interaction existed between an ancient metasomatized lithospheric mantle and asthenospheric melt, which transformed the refractory peridotites with highly radiogenic Sr and unradiogenic Nd isotopic compositions to the fertile lherzolites with unradiogenic Sr and radiogenic Nd isotopic compositions.

Therefore, they argue that the lithospheric mantle represented by the peridotites has been heterogeneously refertilized by multistage melt/fluid-peridotite interactions.

Tang et al. Multistage melt/fluid-peridotite interactions in the refertilized lithospheric mantle beneath the North China Craton: constraints from the Li-Sr-Nd isotopic disequilibrium between minerals of peridotite xenoliths. Contributions to Mineralogy and Petrology, 2011, 161: 845-861  (Download Here)

Fig. Variation of d7Li with Li concentration for minerals in the studied peridotite xenoliths, compared with published data for fresh MORB. (Image by TANG)

Fig. Variation of eSr and eNd for cpx and opx in the studied peridotites, together with the published data for peridotite xenoliths. (Image by TANG)