Tayuan Gold Silver Copper Deposit is located in the north section of Greater Khingan Mountains.Bimodal intrusive rocks (hornblende gabbro and monzogranite) are developed in the mining area.Zircon U-Pb dating results show that the diagenetic age of hornblende gabbro is 325 Ma±2 Ma and that of monzogranite is 324 Ma±3 Ma.The results of element geochemical tests show that hornblende gabbros belong to calc alkaline series,enriched in LREE and large ion lithophile elements (LILE) while depleted in high field strength elements (HFSE);Monzogranite belongs to high-K calc-alkaline series,that is peraluminous rock,enriched in LREE without obvious Eu anomaly.It is characterized by obvious loss of P,Ti and Nb and enrichment of K and Rb.Hornblende gabbro and monzogranite are formed by melting in different homologous areas.The basic rocks are derived from the primitive mantle mixed with continental crust,while the granite may come from underplating.The basic magma causes large-scale partial melting of its upper crust to form granite.The bimodal intrusive rocks in the Tayuan Gold Silver Copper District were formed under the post orogenic extensional tectonic setting,and the collision and amalgamation of the Kingan block and the Songnen block were completed at the end of the Early Carboniferous at the latest.