REE and Sr and Nd Isotope Geochemistry of Mantle Xenoliths from Basalts in Hannuoba
汉诺坝玄武岩中地幔岩捕掳体REE和Sr,Nd同位素地球化学

REE abundances and Sr and Nd isotopic composition in mantle xenoliths from basalts in Hannuoba are reported in this paper. REE distribution patterns and isotopic compositions of different types ofrocks can reflect degrees of partial melting and metasomatic processes in the mantle. Lherzolite depleted LREE is a relict of original mantle rocks at different degrees of partial melting;harzbugite with U-typed REE distribution patterns is a product of highly depleted pyrolite which has been metasomatized by melt in chemical disequilibrium. Websterite vein and neighbouring lherzolite enriched in LREE and MREE are in chemical equilibrium or almost chemical equilibrium, but lherzolite vein might not be related to this basaltic magma. Sm-Nd isotopic geochronology of websterite vein and vein-free lherzolite indicates that vein might be formed at about 0. 3 Ga.