Strata-bound Scheelite Deposit Geology Geochemistry And Genesis, Malipo, Yunnan Province

Nanyangtian scheelite deposit, a large-scale strata-bound deposit, is hosted in the Proterozoic metamorphic formation in Malipo county, Yunnan province, China. There are two types of ore body occurrences, one is layered, plate-shaped, conformably hosted in and synchronal folded with the stratum; the other one is vein-type, which interludes the layered ore body, with mineralization enriched locally. The host rocks include skarnlike, leptynite, (mica-quartzite) schist, tourmaline and monzonite et al. Base on field investigation in-depth and laboratory testing of rocks and mineral identification as well as geochemical studies, the author systematically summarizes the geological and geochemical characteristics of the deposit. Through comparative study of the deposit to the similar deposits in domestic and overseas, the stratified tourmaline and striped feldspathose rocks are suggested to be submarine exhalation genesis, and the vein type tourmaline is magmatic hydrothermal genesis. Based on the above analysis, the author put forward that Nanyangtian sheelite deposit is Proterozoic submarine (volcanic) exhalation-metamorphosed-magmatic hydrothermal superposition and reformation in Yanshan epoch, and subsequently establishes a three-stage mineralization model. Furthermore, the author points out that "prospecting along the bedding" is a principle for the type of deposits, and the layered skarnlike can be served as the ore indications. There are similar geological conditions and ore prospecting potential in the neighboring Ha Giang province, north Vietnam.