Hunan Yaogangxian Greisen Tungsten Ore Analysis Vitro Studies

Yaogang tungsten deposit is one of the most important of Chinese tungsten industry. The mining area mainly consists of two super large tungsten deposits:quartz vein type wolframite and skarn type scheelite (not mined yet), and smaller lead-zinc deposits.This paper focuses on the ore-forming geological body of quartz vein type wolframite deposit in Yaogangxian-the schlierens of greisen in medium grained porphyry alkali feldspar granite. The main study contents are shown below. In terms of geology, find out the distribution feature of the main schlieren of greisens, make systematic sampling and microscope analysis of greisen’s schlieren, make clear of the texture, structure, mineral composition and variation in content, etc. In terms of geochemistry, make systematically electron microscope analysis in the major minerals in the schlieren of greisen (such as feldspar, mica and wolframite), make major trace element and rare-earth element geochemical analysis and test in the schlieren of greisens, analyze the inclusion in schlieren, and find out the main geochemical characteristics.Through the geological and geochemical study of the schileiren system of greisens, a few things were made clear:(1) The schlierens of greisen are separately distributed in medium grained porphyry alkali feldspar granite and have an ellipsoidal distribution pattern. There is no contact between schlierens and no alteration is seen in wall rocks. The geological characteristics of greisen’s schlierens show that they are the products of fluid phase differentiation of magma;(2) Through the integrated analysis of petrography, mineragraphy, the electron probe analysis of compositional characteristics of major minerals, major trace element geochemical characteristics, rare-earth element geochemical characteristics and fluid inclusion of the greisen’s schlieirens, it is concluded that the formation of the greisen’s schlieirens are affected by the joint effect of magma and hydrothermal fluid. The schlieirens of greisens are formed by the fluid-liquid phase differentiation evolution of magma-hydrothermal transitional state between magma and hydrothermal fluid.(3) The mineral composition of the core of greisen’s schlierens and the characteristics of fluid inclusion of greisen’s schlierens are consistent with the quartz vein of wolframite. The magma-liquid transitional phase fluid that formed the schlierens of greisen was further enriched in volatile and hydrothermal fluid, finally differentiated and produced the quartz vein of wolframite. The formation of quartz vein type wolframite was started in the late magma stage, not the post magma stage that was formerly admitted.(4) The study in the schlieren of greisens not only holds substantial theoretical significance but also substantial economical significance as it is both an ore body and an important clue in finding quartz vein type wolframite.