A study of the genesis of igneous rocks from the Sankuanggou Cu-Fe-Mo deposit in Heilongjiang Province

Located along the Sankuanggou-Duobaoshan tectonic-metallogenic belt in Da Hinggan Mountains, the Sankuanggou skarn-type Cu-Fe-Mo deposit is a typical skarn-type deposit. On the basis of field geological survey and indoor rock ore identification, the authors analyzed the lithogeochemical characteristics of Sankuanggou (granite) tonalite related to metallogeny, and discussed the genetical type and tectonic setting of this rock mass. Studies show that the magmatic rocks of this deposit belong to the calc-alkaline I-type granite, with the characteristics of continental crust, and that these magmatic rocks were formed in a volcanic arc tectonic environment or a similar environment, mainly having close relationship with volcanic arc granite orogenic phase. REE distribution patterns show LREE-enriched patterns with gently rightly inclined shape, and strong REE fractionation with no pronounced negative Eu anomaly, suggesting that these magmatic rocks have the same or similar genesis and reflect the characteristics of comagmatic region. δEu values vary from 0.81 to 1.24, δCe values range from 1.00 to 1.13, indicating that weak fractional crystallization occurred in the process of magma evolution, with some influence of assimilation and contamination, and that their low oxygen fugacity of diagenetic environment might imply some anoxic environment.