Geochemistry of apatites from Mesozoic granitoids in the northeastern North China Craton and their petrogenetic implications

Abstract We report geochemical data of apatites from Mesozoic granitoids in the northeastern North China Craton (NCC), and discuss the relationship between apatite and whole-rock compositions with the aim of using apatite geochemical data to constrain granitoid petrogenesis. Measured Sr contents and Sr/Y ratios of apatites exhibit positive correlations with those of their host rocks, and eNd(t) values of apatites display a strong linear relationship with eHf(t) values of zircons in the granitoids. In addition, apatites exhibit similar rare-earth element (REE) distribution patterns with their host rocks, although apatites have much higher REE contents. Sr/Y–Y variation diagram for apatite is proposed to distinguish adakitic rock from non-adakitic. The REE patterns of apatites, together with other geochemical indexes, can also be used to discriminate highly fractionated granitoids from unfractionated I-type granite or other type granite. The geochemical and Nd isotopic compositions of apatites have well revealed the magma source of Mesozoic granitoids in the northeastern NCC. In conclusion, we highlight that apatite geochemistry reflects the whole-rock geochemical characteristics of granitoids and has the potential to track granite detritus.