Petrogenesis of granite from Xiaofan Mo deposit, Dabie Orogen

Abstract

The Mesozoic granitoids in the Dabie Orogen are of particular geological interest as indicators for Mesozoic lithospheric evolution because of their close association with porphyry Mo mineralization. Here, we present a study using petrogeochemistry data to constrain the petrogenesis of the Xiaofan granites in the Dabie Mo mineralization belt (DMB), Henan Province, China. Field investigations show that the Xiaofan pluton mainly consists of porphyritic granite. The Xiaofan granites have high SiO2 contents of 74.29 wt%–76.07 wt% (average: 75.18 wt%), Al2O3 contents of 11.66 wt%–12.83 wt% (average: 12.13 wt%), and K2O contents of 5.37 wt%–7.90 wt% (average: 6.86 wt%) and low MgO (0.06 wt%–0.16 wt%), TiO2 (0.09 wt%–0.10 wt%), and P2O5 (0.047 wt%–0.103 wt%) contents. They are enriched in Rb, U, K and Hf but depleted in Ba, Nb, Ta, Sr and Ti. By geochemical and mineralogical features, we propose that the Xiaofan granites belong to A-type type granite and dominantly sourced from the crust. The granites from the Xiaofan Mo deposit may have formed in a post-collision extensional setting.