西准噶尔包古图铜金矿带位于达拉布特岛弧南部,包古图地区的一些小型斑岩体与铜金矿化关系非常密切,其岩性以闪长岩和石英闪长岩为主.矿物学研究发现,本区斑岩体中角闪石具镁角闪石成分特征,黑云母属镁质黑云母,斜长石为中长石.矿物化学成分显示含矿斑岩的成岩物质主要来源于地幔,并有少量地壳物质加入.本区岩石类型属钙碱性花岗岩类,与俯冲作用有关,是相对高温(800℃)和较高氧逸度条件下的产物.据含矿岩体矿物化学成分估算,包古图含矿岩体的形成压力范围在230~390 MPa.
The Baogutu copper-gold belt is located in the southern part of the Darbut arc in West Junggar,and the copper-gold mineralization are closely associated with some small porphyry plutons which are dominately composed of diorite and quartz diorite.Detailed mineralogical investigation demonstrated that amphibole and biotite in the porphyries are of Mg-rich types and plagioclase belongs to andesine.It is concluded that the porphyries are calc-alkaline rocks from a subduction environment and have been chiefly derived from a mantle source with minor crustal contamination.Based on the mineral compositions,it is estimated that the ore-bearing rocks were formed at a temperature of about 800℃ and a pressure of about 230~390 Ma,with relatively high oxygen fugacities.