In Situ Geochemical and Sr–Nd Isotope Analyses of Apatite from the Shaxiongdong Alkaline–Carbonatite Complex (South Qinling, China): Implications for Magma Evolution and Mantle Source

We present in situ major element, trace and Sr–Nd isotope data of apatite from an alkaline–carbonatite intrusion the South Qinling Belt (SQB) to investigate their magma evolution mantle sources. The Shaxiongdong (SXD) complex consists predominantly early Paleozoic hornblendite, nepheline syenite, subordinate Triassic carbonatite. Apatites all lithologies are euhedral subhedral belong fluorapatite. Elemental substitution varies REE3+ + Na+ Sr2+ ? 3Ca2+ carbonatite syenite Si4+ 2Na+ 2S6+ 4REE3+ 4P5+ 5Ca2+ hornblendite apatite. characterized by enriched rare earth elements (REEs) depleted high field strength (HFSEs). They record distinct parental magmas. weak, negative Eu anomaly apatite, together with lack anomalies bulk rocks, indicates a relatively reduced magma. SXD carbonatite, falling on East African line (EACL) close Oldoinyo Lengai indicate that is derived mixed source consisting HIMU component subducted sedimentary carbonates. similarity Sr Nd isotopic compositions between apatites mafic-ultramafic dykes SQB suggests they may share common metasomatized lithospheric source.