| Obulage copper gold deposit is located in Inner Mongolia,in the northwest part of North China plate and the west part of Langshan Zhaertai rift zone.In this study,garnet and other skarn minerals are found in the ore body,and the genesis of the deposit is controversial.According to the field geological mapping,mineralogy,mineralogy and isotope testing methods,this paper explores the metallogenic characteristics and metallogenic mechanism of the deposit.The main achievements of this paper are as follows:(1)sulfide like droplets are found in quartz porphyry in the mining area,which are mainly dark yellow,grayish yellow and yellowish brown in color;The shape is mainly round,oval,flat strip and other irregular shapes;The size is2 mm-5 cm in diameter;It is mainly composed of chalcopyrite,pyrite,galena,sphalerite,pyrrhotite,arsenopyrite and other metal minerals,as well as quartz,calcite,mica,epidote,chlorite and other transparent minerals.(2)There are a lot of cryptoexplosive breccia on the surface of the mining area,and the metal and garnet in the ore of the mining area are broken by fluid,which proves the existence of fluid overpressure.(3)Sulfur isotope characteristics indicate that the sulfur in the deposit mainly comes from deep magma and sulfur rich country rocks.It is speculated that the metallogenic mechanism of the deposit may be as follows: in the deep magma chamber,the basic magma reacts with sulfur rich and carbon rich country rocks to form garnet skarn and then sulfide slurry,which gradually accumulates at the bottom of the magma chamber due to the large proportion of sulfide slurry.In the late stage of magmatic evolution,due to the addition of sodium rich and silicon rich fluids into the magma chamber,the copper rich gold melt fluid("slurry")was formed,and the fluid overpressure was gradually formed.Finally,the copper rich gold melt fluid flow rapidly intruded and emplaced along the magmatic channel(structural weak zone). |
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