PROSPECTIVE VALUE OF THE SOUTHEAST JIAPIGOU GOLD MINERALIZATION BELT

Jiapigou Au-mineralization belt is a large-scale one.The wall rocks of gold deposits in the belt are metamorphic rocks of Archean and mantle-derived granites,and the structures that control Au-mineralization are large-scale shear zone and faults accompanying ductile shear zone. The main Au-mineralization occurred in 2455~2469 Ma and 180~90 Ma, corresponding to the peaks of mantle-derived magmatic activities. The compositions of inclusions in the quartz form ore are rich in Na⁺,Mg²⁺,SO₄^2-,CO₂,CH₄ and C₂H₄.The f_O2 is low while f_CO2 is high.The values of isotopic compositions for ore are respectively W³²S=-0.73, W¹³C=-4.83, ⁸⁷Sr/⁸⁶Sr=0.703, X_Nd (t)=8.4,illustrating that the ore-forming materials come from the mantle. The fluids of Au-mineralization have three characteristics:(1)The fluids for two main mineralization epochs come from the same source.(2)The isotopic compositions of fluid have well homogeneity,showing that the volume of fluid source is large.(3)The fluids are C-H-O system and rich in CO₂,CH₄ and C₂H₄,the value of water/rock is high.The characteristics of fluid are the same as those of the fluids from mantle.
Xinlitun-Majiadian and Dachaoyanggou areas have the basic ore-forming conditions which are Archaen metamorphic rocks, mantle-derived magmas and ductile-brittle faults. In the areas,many Au-mineralization places are discovered, such as Xinlitun, Majiadian, Nanshan etc. The Au-quartz veins are controlled by faults near Jiapigou large scale ductile shear zone, and the wall rock alteration associated with Au-mineralization are silicification and potash feldspathization. There are metal-sulphides such as pyrite, chalcopyrite, galena and sphalerite in the Au-quartz veins, and the gold grade changed with the quantity of metal-sulphides. To summarize,the Au-mineralization characteristics in the area are the same as those in Jiapigou Au-belt.
There are similar characteristics in Majiadian and Dachaoyanggou areas.So,the area of southeast Jiapigou Au-mineralization belt is potential for prospecting.