In situ chemical and Sr–Nd–O isotopic compositions of apatite from the Tongshi intrusive complex in the southern part of the North China Craton: Implications for petrogenesis and metallogeny

摘要: Abstract The Tongshi intrusive complex from the southeastern margin of North China Craton is composed syenite and monzonite, was emplaced at ca. 180 Ma. Apatite monzonite were analyzed to better understand petrogenesis its mineralization potential. cathodoluminescence images some apatites exhibit core–rim texture, whereas display uniform inner texture. core rim domains distinct Sr isotopes major–trace element compositions, only little variation displayed by oxygen isotopes. portions inferred be inherited protolith during remelting process. calculated δ18O values range 3.5‰ 4.1‰ with an average 3.8‰ (SE = 0.21), which significantly lower than that sample (with a 6.4–6.9‰, mean 6.7‰). In conjunction heterogeneity Nd isotopic compositions normalized 143Nd/144Nd ratios varying 0.51151 0.51236, eNd (t = 180 Ma) −20.3 −4.8) syenite, it proposed melts may have been contaminated crustal components earlier hydrothermally altered high temperature. Based on diffusion theory, we calculate temperature this contamination higher 637 °C, closure Sm–Nd in apatite, estimate duration process probably shorter 0.13 Ma. fugacity apatite Mn content indicate oxidization state magma can enhance metallic contrast, melt unfavorable for metal enrichment, thus leading insignificant mineralization. Our study recommends more focus gold exploration rocks syenitic affinities region.