Study On Mineralization Regularity And Formation Mechanism Of Scheelite And Wolframite In The Woxi Au-Sb-W Deposit In Hunan Province

The Woxi Au-Sb-W deposit situated in the central sector of Xuefengarc-structural mole track which its tectonic line direction from north east to the thingturning parts.It is an important producing area of gold-antimony-tungsten and famousat home and abroad for the paragenesis of gold-antimony-tungsten,large scale,uniquetype and ore body obliquely extending far outweigh the trend.The geological research of this deposit is high,but there are different opinionsabout ore gendsis,for example,postmagmatic hydrothermal solution,metamorphichydrothermal fluid,sedimentary exhalative,etc. and low research of new miningsegment and ferberite.Based on the works of predecessors,we did our study by fieldobservation in the tunnels,collecting lots of rock and ore samples and thin sectionidentification,x ray diffraction test,electron microprobe test,oxygen and sulfurisotope test.Thus we made research on composition characteristics and type ofwolffamite.We also summary and analysis the relationship between strata,lithology,tectonics and mineralization and mineralization regularity from the regional andgeological background.Based on the sources of ore-forming material, characteristicsof ore-forming fluid analysis, the ore forming process are discussed.The major points described as follows:1. The tungsten mineral phases are ferberite,and components can be divided into lowMn content ferberite and high Mn content ferberite.2. Stratum and tectonic ore control obviously,Ma di yi group purple slate ore bearingrates first,followed by Wu qiang xi group,last the Leng jia xi group. Xuefengarc-structural mole track and the development of fracture controlls deposit appearance.The orebodies occurs in consistent with formation and ore body obliquely extendingfar outweigh the trend.3. Migration of element, REE patterns, oxygen and sulfur isotope reveal that thesource of ore-forming material originate from strata. 4. The ore-forming fluid is weakly acidic and alkaline, middle-low temperature, lowsalinity,low pressure and metamorphic hydrothermal mainly.5. Tungsten can migrate as the form of complex,such as [HW₆O₂₁]^5-,[H₃W₆O₂₁]^3-,[H₂W₁₂O₄₀]^6-,ect.Gold is likely to as the form of [Au⁺S]^-,and antimony as SbH₃.Theyall can enrich and mineralize when the physical chemical conditions of environmentalchanges.