Su, B.-X.Zhang, H.-F.Yang, Y.-H.Sakyi, P.A.Ying, J.-F.Tang, Y.-J.2019-01-212019-01-212012-03Su, BX., Zhang, HF., Yang, YH. et al. Miner Petrol (2012) 104: 225. https://doi.org/10.1007/s00710-011-0190-6https://doi.org/10.1007/s00710-011-0190-6Volume 104, Issue 3–4, pp 225–247http://ugspace.ug.edu.gh/handle/123456789/26924Major and trace element compositions of constituent minerals, partly decomposed rims of orthopyroxenes (DRO), 'closed' melt pockets (CMP) and open melt pockets (OMP) in some Western Qinling peridotite xenoliths were obtained by LA-ICP-MS. Systematic core-to-rim compositional variations of garnet, clinopyroxene and orthopyroxene demonstrate that these minerals underwent variable degrees of subsolidus breakdown or partial melting. Both DROs and CMPs consist of similar mineral assemblages and are characterized by high TiO 2, CaO + Na 2O and low MgO contents; they are enriched in LREE and LILE compositions, have positive anomalies in Pb, Sr and particularly Ti, negative Th and U, and variable Zr and Hf anomalies. These chemical features are distinct and reflect reactions involving the orthopyroxenes. Compared to the CMPs, the OMPs, which are composed of a complex assemblage of minerals, display lower FeO and MgO contents, larger ranges in SiO 2 and Na 2O, higher TiO 2, Al 2O 3, CaO and trace element concentrations, slightly negative Zr and Hf anomalies, and apparently negative Ti anomalies. Modeling calculations of partial fusion of orthopyroxenes and clinopyroxenes suggest that the CMPs most likely originated from the breakdown of orthopyroxenes with variably minor contribution of external melts from the melting of clinopyroxenes, whereas the OMPs were probably formed from the modification of the CMPs through the interaction with large amount of external melts. © 2011 Springer-Verlag.enorthopyroxenemantle peridotite xenolithsLA-ICP-MSdecomposed rims of orthopyroxenes (DRO)Article