Nine pieces of gabbroic xenoliths from Hannuoba were examined for theirmajor and trase elements and Nd, Sr and Pb isotopes. The results show that the gabbroic xenoliths are of moe mafic basaltic composition. Their abundances show narrowvariations in major elemeats. The trace element contents are highly variable in contrastwith those of host basalts and lherzolite xenoliths. The gabbroic xenolitho are rich inNd (0.51159-0.51249), Sr (0.70491-0.70768) and low in radiogenic Pb(16.283-17.046,15.191-15.381 and 36.999-37.476), significantly different from basalts and lherzolites inisotopic space. The calculated Nd and Pb model ages are about 3.0-3.5 Ga. The rockshave relatively bo equilibrium T(~85℃) and P (0.8-0.9 GPa). They could be interpreed to be the product of upper mantle melting at the boundary between the lowercrust and the upper mantle. Their chemical and isotopic variations can be ascribed todifferent degrees of melting, segregation and long-term evolution.
