Recognizing juvenile and relict lithospheric mantle beneath the North China Craton: Combined analysis of H 2O, major and trace elements and Sr-Nd isotope compositions of clinopyroxenes

Recognizing juvenile and relict lithospheric mantle is crucial in unraveling the mechanism of lithospheric thinning (delamination vs. thermal/mechanic erosion). The H2O contents and Sr–Nd isotopic compositions of juvenile lithospheric mantle are expected to be similar to the MORB source (asthenospheric mantle), whereas those of the relict lithospheric mantle should be of typical cratonic character. Consequently, combined analysis of H2O contents and Sr–Nd isotope compositions could be an effective way to distinguish the juvenile and relict lithospheric mantle. Among the peridotite minerals, clinopyroxene is the major host for rare earth elements as well as H2O contents, making it the most suitable target sample for such analyses.