Geochemistry of mafic-ultramafic rocks from northern Dabie complex and its implication

摘要

Twelve samples of Jiaoziyan gabbroic rocks and four Zhujiapu pyroxenites from Northern Dabie complex were analysed for major, REE and trace elements. Major elements of gabbroic rocks show fractional crystallization during its magma evolution. The LREE-enriched and HFSE-depleted characters of gabbros and pyroxenites, together with their Nd and Sr isotopes indicate the involvement of terrestrial material in mantle source, probably related to its subduction. The chemical and isotopic signals for gabbros and pyroxenites aren't correlated to oceanic ophiolitic melange, but reflect their affinity of transition from active continental margin to island arc magmatism.