GEOLOGICAL CHARACTERISTICS AND GEODYNAMICAL SETTING OF THE XIAOFAN MOLYBDENUM DEPOSIT IN HENAN PROVINCE

The Xiaofan molybdenum deposit is a typical porphyry deposit in the northern margin of East Qinling-Dabie Mountain. The Xiaofan rock mass, which related to Mo deposit, comprises two intrusive bodies. The first intrusion is dominated by porphyry granite. The second consists of mainly porphyritic granite. The metallic minerals in the ore include mainly molybdenite and pyrite, with gangue minerals dominated by quartz. The mineralization shows the change in the structure of ores from veinlet to dissemination and crumb. The metallogenic age of the deposit is 142 Ma or Early Cretaceous, which is the same time as those of Jinduicheng and Nannihu Mo deposits. Thus they belong to the second mineralization epoch of East Qinling-Dabie molybdenum metallogenic belt. The metallogenic event took place in the postIndosinian Dabie orogenic belt when the tectonic system was transiting from compression to regional extension.