Geochemical Characters Of Trace Elements In Xin Kangmao Gold Deposit Which Locates In Hong Yuan, Si Chuan

Xin Kangmao gold deposit locate in the area which was formed by Songpan~Ganzi geosyncline in the west of Qinling orogen, the south of Aba plate and Long Menshan tectonic zone which towarded northeast. The deposit is dissemination gold deposit, and was found in the latest years, so this deposit also has the common and representative characters of Carlin-type gold depostis. This article starts from trace elements and rare earth elements, and respectively discusses the elements of wall rocks, ores and minerals, compares with each other lengthways, and at last contrast correlative elements of the deposit with the lavers of the earth. According to the results of contrast, we can study the source of substance, at the same time, we can also intensively realize the deposit. In this research, we picked out samples under microscope and lap minerals, and then got the data by neutron activation analysis.The wall rocks where the ore exist compose a suit of low grade metamorphic rocks. We can classify these wall rocks by the difference of their granularities, and they are conglomerate, sandstone, siltstone and mudstone (slate).The ores mainly are clastic rock, the mylonite and cataclasite formed in tectonism.Combination of minerals: during ore minerals, pyrite and limonite account for much, and chalcopyrite, arsenopyrite, sphalerite and natural gold and so on are secondary. In gangue minerals, feldspar, quartz and clay mineral are major, in contrast, calcite and graphite are minor. There are widely metamorphosing in wall rocks, and the main are sericitization, silicification, pyritized(limonitization) and carbonation, besides these there are also clay, stibnitized, chalcopyritized, graphitization etc. The intensity of metamorphosing is closely relative with gold mineralization.There are the conclusions as follows:Au, As, Ag,, W in wall rocks are less compared with the ones in ores, but much more than Clarke values, conclude that the substance of ore came from formation, maybe the mineral hydrothermal fluids from the deep also affected the mineralization.Comparing trace elements in wall rocks with the ones in ores, mineralization substance mainly came from wall rocks. But Zr and Hf in some ore samples are much less, this reflects that source of substance may have correlation with deep liquid. from mantle.Representative characters of minerals: Co in pyrite are between 98.4 and 152.5ppm. In most pyrites, Co is less than Ni, but in particular pyrite, Co is more than Ni. We can conclude wall rocks and deep hydrothermal liquid jointly influenced the mineralization. The good correlation between Au in quartz and Rb, Zr, Hf also reflects this conclusion.Comparing rare earth elements and their characters in wall rocks, rock dykes and ores, ores are more proximity with rock dykes. It reflects that not only wall rocks, but also magma and hydrothermal liquid work in mineralization. During the minerals, except pyrites, the characters of rare earth elements in quartzes and calcites are different with the ones in wall rocks. Comparing with the other earth layers, the characters of rare earth elements in quartzes are more proximity with lower crust.From all the evidences above, we can conclude that: the main substance source of mineralization in Xin Kangmao deposit was wall rocks, but deep hydrothermal liquid also worked in the mineralization process.The Co/Ni in pyrites are mostly less than 1, particularly more than 10, this reflects the deposit is low medium temperature deposit.The mineralization process has undergone multistage hydrothermal liquid reform action. Evidence: the difference between trace elements in coarse grained quartzes and fine grained are large.The quartzes in Xin Kangmao gold deposit are similar with the mantle, implying the source of substance was relative with mantle.