Compositional and isotopic heterogeneities in the Neo-Tethyan upper mantle recorded by coexisting Al-rich and Cr-rich chromitites in the Purang peridotite massif, SW Tibet (China)

•High-Cr (Cr#Sp: 62.55–79.57) and high-Al (Cr#Sp: 47.60–57.56) podiform chromitites coexist in the Purang peridotite massif.•They show enrichment in IPGE over PPGE and their PGM assemblages are dominated by laurite.•γOs values are generally negative indicating a sub-chondritic mantle source for the parental melts of chromitites.•The Purang chromitites originated from geochemically distinct magma inputs derived from melting of different sections of a mantle wedge above a SSZ.