| The tungsten deposit of Shigushan locate in central-eastern Nanling,which is the important part “W-Sn ore area of Shixing in Guangdong”.The large quartz vein and small quartz vein is the most important type of ore,On the basis of summarizing the geological background and metallogenic characteristics of Shigushan tungsten deposit,elements geochemistry,fluid geochemistry and stable isotope geochemistry are systematically research in this paper.From this,the Ore-forming&Ore fluid-forming &genesis mechanisms of the deposit be analyzed.Major points are as follows:(1)ShigushanYanshanian granitic was with high silicon,alkaline,strong peraluminous,High differentiation,crust characteristics;porphyritic granite characterized by rich elements of Rb,Cs,K,high field strength elements Th,U,Pb and Li are high,and the loss of Sr,P,Ti;The total amount of ?REE range from 106.8×10-6 to 163.9×10-6,average 135.8×10-6,the relative enrichment of light rare earth elements,with obvious loss of Eu,rare earth element distribution pattern was the "V" form.(2)The important surrounding rock are Cambrian slate of this tungsten deposit.The metallogenic elements(W,Sn,Cu,Pb,Zn,Bi)are enriched.(3)Pyrite trace elements show that the deposit belong to hydrothermal genesis,molybdenum trace elements show that it comes from the crust.The rare earth elements is similar to the magmatic rocks,which shows that the ore from magmatic rocks,the enrichment of light rare earth elements in molybdenite,which indicates that CO2 and Cl or F As well as some reducing gas are rich in the ore fluids.(4)The study of fluid inclusions shows that the mineralization temperature in this deposit is between 180?and 360?,and the temperature has many peaks,which shows that many ore fluids generated in Shigushan tungsten deposit.The ore fluids are mixed with the low-temperature and low-salt fluids.The salinity and density is within 2.5wt%~7.5wt%NaCleqv and 0.80g/cm3~0.90g/cm3.The metallogenic pressure is within 15 MPa ~ 25 MPa,depth of ore deposit is within 1.5 ~ 3.0km.In addition,the ore fluids has been boiled,and mixed with low-temperature and low-salt fluids,indicating that the physical and chemical conditions have changed,which may be an important mechanism for the tungsten deposit are formed.(5)The study of the stable isotopic characteristics of the Shiguoshan mining area shows that the ?34S value is between-0.4 ‰ and 1.0 ‰,the sulfur isotope is 0.5%,close to zero,and is consistent with the characteristics of deep source sulfur(0±3).The carbon-oxygen isotopic composition indicates that the carbon in the ore may be from the deep magmatic water,and the carbon-oxygen isotopic composition of ore fluids from the deep magmatic water,mixed with part of the organic carbon(6)Shigushan tungsten deposit is a typical magmatichydrothermal deposit,the Yanshannianmagmadominate the mineralization occurred.Through the comprehensive study of the geological characteristics,ore-controlling factors,ore-forming material source,diagenetic age and metallogenic mechanism of the Siguoshan tungsten deposit,it is shown that the Siguoshan tungsten deposit has the characteristics of magmatic hydrothermal deposit,Ore-forming materials,ore-forming fluids mainly from deep-source magma,may have a small amount of Cambrian metamorphic rocks,and mineralization.The magma from the deep source can bring ore-forming material on the one hand,which can provide a heat source for the activation of the ore-forming material,which provides favorable conditions for the migration of the ore-forming material and enrich the precipitation and mineralization in the proper position. |
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