The Hersai porphyry copper deposit occurs in quartz diorite bedrock. There are three directions of fault structure in mining area: NNE, NEE and NW. There are various types of intrusive rocks in the mining area, including quartz diorite, granodiorite porphyry, potash granite, sodalite porphyry and various dikes. Quartz diorite is grayish white, mainly composed of quartz, biotite, plagioclase and amphibole. Granodiorite porphyry intrudes into granodiorite, often in the form of small rocks or dikes, generally in the north-south direction; The rocks are porphyritic, with plagioclase as the main phenocryst and a small amount of biotite and amphibole. The matrix is microcrystalline plagioclase, quartz and biotite. The top of the edge of granodiorite porphyry is often accompanied by cryptoexplosive breccia. The breccia is composed of granodiorite and potash granite. The cement is composed of aphanitic, fine-grained feldspar detritus and biotite, and porphyritic or banded chalcopyrite can be seen in the cement matrix. K-feldspar granite mostly occurs in the form of irregular residues, and K-feldspar granite breccia is found in quartz diorite and granodiorite porphyry (Figure 4. 1a). The dikes are mainly diorite porphyrite dikes, fine-grained granite dikes, calcite dikes and chronological dikes.
The zircon CAMECA U-Pb dating results show that the age of potash feldspar granite (ZK 107- 1-9) is 429Ma, that of quartz diorite is 4 1 1Ma, and that of granodiorite porphyry (ZK107
The surface mineralization alteration in the mining area is mainly related to granodiorite porphyry, including copper, copper-molybdenum and copper-zinc ores. Ore can be divided into vein mineralization in quartz diorite and granite, disseminated vein mineralization and veinlet mineralization in granodiorite porphyry, and mass and vein mineralization in cryptoexplosive breccia. Re-osmium dating of molybdenite shows that the metallogenic age is 409Ma.