Indosinian Mo mineralization in Qinling area and prospecting potential

Abstract：Three types of Indosinian Mo mineralization can be observed in the Qinling area, namely carbonatite-type, fault-controlled quartz vein type and porphyry type. Carbonatite-type Mo deposits are represented by the Huanglongpu and Huangshuian deposits. They are spatially and genetically associated with magmatic carbonatite, and the ore bodies are present as Mo-bearing carbonatite veins, with specific Mo+U+REE mineralization. Fault-controlled quartz vein type Mo deposits are represented by the Waifangshan Mo ore district (composed of Zhifang and Qianfanling Mo deposits), Dahu Au-Mo deposits and Majiawa Au-Mo deposits. They occur as fault-controlled quartz veins, and the hydrothermally altered wall rocks can be mineralized, either. Such deposits share similar geological and fluid inclusion features with the orogenic type deposit, and are regarded as its medium to high temperature endmembers. Porphyry-type Mo deposits, represented by the Wenquan Mo deposit, are associated with Indosinian intermediate-acid granite porphyry, and molybdenite crystals occur as veinlets or veinlet-disseminations. Typical porphyry type hydrothermal alterations include potassic alteration, phyllic alteration, chloritization, epidotization and carbonation. It is concluded that the carbonatite-alkali rocks in the northernmost part of the Qinling Orogen are in favor of carbonatite-type Mo mineralization, the area between Machaoying fault and Sanbao fault in the southern margin of the North China Craton is favorable for fault-controlled quartz-vein type Mo mineralization, and quartz vein type Au-Mo deposits can be found in Xiaoqinling and Xiong'ershan regions. Emphasis should be placed on Indosinian granite and related Mo mineralization in East Qinling area.