Characteristics Of Fluid Inclusions And Race Elements Of Donggualin Gold Deposit

Ailaoshan area is the structure transition zone of Himalayan orogen belt, and it is an important place to produce gold in China.. The paper takes Donggualin as an important gold deposit, Laowangzhai Gold Deposit and many other gold deposit near by. At last, we summarize the characteristics, formation and material source of gold deposits here, and expected to predict the deep ore body in the West open pit of Donggualin through the analysis of race elements.Through Donggualin gold deposit, Laowangzhai gold deposit and other gold deposit in Ailaoshan area, the results are as follows. (1) Most gold deposits have two or more major mineralization stages from the homogenization temperature, of which Donggualin and Laowangzhai get 2. (2) The homogenization temperatures fall in the range of 100~400°C, mainly concentrate in 110~310°C. It shows that they are gold deposits of middle-low temperature. (3) The salinities are from 0—21%, mainly in 5%~18%, and increase with the homogenization temperature raising. The densities are from 0.6 ~1.06g/cm3, mainly in 0.8~1.05 g/cm3. (4) The ore-forming process occurred in depths of mid-shallow. (5) Metallogenic epoch of the gold deposits is probably early Himalayan period. (6) Sulfur isotopes illustrate that it is from mantle. (7) Hydrogen oxygen isotopes show that the ore-forming hydrothermal solution consists of meteoric water, magmatic water and metamorphic water.The analysis of race elements in Donggualin Gold Deposit shows that Au is closely related to Co, Ni, Cu, Sn and As, which indicates that Au may come from the mantle. Axial zoning sequence of primary halos, from top to bottom, is defined as As—Bi—Mn—Pb—Sb—B—Sn—Cu—Hg—Co—Mo—Ag—Au—Zn—Ni. From that, we can see that there are many mineralization periods. The results also illustrate the coexistence of frontal and rear halos and the opposite direction zoning feature of primary halo in Donggualin Gold Deposit, from which it can be predicated that blind ore probably occurres in deeper place. To sum up, the model of primary halos in Donggualin Gold Deposit is similar to the ideal model of two key mineralization periods in gold deposits.