Major element geochemistry of apatite from Fe-Ti-V oxide-bearing mafic-ultramafic intrusions in the Emeishan large igneous province and their petrogenesis and mineralization
Major element geochemistry of apatite from Fe-Ti-V oxide-bearing mafic-ultramafic intrusions in the Emeishan large igneous province and their petrogenesis and mineralization
Mafic-ultramafic intrusions of Hongge,Panzhihua and Taihe in the Emeishan large igneous province host super-large Fe-Ti-V oxide deposits.The major elements of apatite are used to reveal the conditions for petrogenesis and mineralization of these intrusions.The apatite crystals of Hongge,Panzhihua and Taihe intrusions are rich in F(0.94%~1.83%),and poor in Cl(0.10%~0.66%)as well as SO3(<0.25%).The F contents are negatively correlated with the Cl contents and positively correlated with the F/Cl ratios,while no obvious correlations occur between SO3 and F contents.Compared with the apatite crystals from the ore-bearing gabbro samples from Panzhihua and Taihe intrusions,the apatite crystals of ore-bearing olivine clinopyroxenite and clinopyroxenite samples of the Hongge intrusion have higher F contents and SO3 contents,but lower Cl contents.The halogen and sulfur contents in the melt can be calculated based on the corresponding values in apatite.It is shown that the magma in which the Panzhihua intrusion in equilibrium with apatite has the highest Cl content.The S content in the Hongge parent magma is higher than those of the Panzhihua and Taihe parent magma.The Cl contents in clinopyroxenite are lower than those in olivine clinopyroxenite from the Hongge intrusion,indicating degassing occurred in this intrusion.Due to the lack of a clear correlation between apatite δCe and SO3 contents,the contents of SO3 in apatite crystals from different intrusions in the Emeishan large igneous province may be related to the S content in the melt.The apatite crystals have high F/Cl ratios,suggesting the mixing of subducted sedimentary materials in the mantle source of the Emeishan large igneous province.
关键词
成矿条件/富F熔体/镁铁-超镁铁质侵入体/钒钛磁铁矿矿床/峨眉山大火成岩省
Key words
Metallogenic conditions/F-rich melt/Mafic-ultramafic intrusions/Fe-Ti-V oxide deposit/Emeishan large igneous province