内蒙古阿拉善左旗古腊布陶勒盖金矿地质特征及矿床成因探讨

Geological Characteristics and Origin of Gurab Tolgoi Gold Deposit in Alxa Left Banner in Inner Mongolia

古腊布陶勒盖金矿床位于阿拉善地块巴彦乌拉山中段,金矿体均受韧性剪切带及EW向、NE向、近SN向断裂控制。赋矿层位为褐红色赤铁矿化绢云母石英糜棱岩,不论是石英脉型金矿,还是蚀变岩型金矿均产于这类岩石中,具有一定的层控特征。矿床经过了中元古代原始沉积地层预富集,后期经过改造富集形成了现在的金矿体。脉内矿物中强烈的热液蚀变和矿石中浸染状、角砾状的构造,显示了岩浆热液矿床的特征。在前人研究的基础上,综合分析区内花岗斑岩和矿床特征,认为古腊布陶勒盖金矿床是古亚洲洋整体于三叠纪闭合、石炭纪末期至三叠纪发育了古亚洲地区规模宏大的成矿事件的响应,矿床类型应为花岗岩叠加改造的韧性剪切带金矿。

Gulabo Tolgoi gold deposit is located in the middle of Bayanwula mountains in Alxa block.The gold ore body is controlled by ductile shear zones and faults with the trend of EW,NE and nearly SN.The ore-bearing horizon is brown-red hematized sericite quartz mylonite.Both quartz vein type gold deposit and altered rock type gold deposit occurred in this type of rock,which has certain layer controlling characteristics.The ore deposit is pre-enriched from the original sedimentary strata of the middle Proterozoic,and later transformed and enriched to form the current gold ore body.The strong hydrothermal alteration in the vein minerals and the disseminated and brecciated structure in the ore show the characteristics of the magmatic hydrothermal deposit.Based on previous studies,the characteristics of granite porphyry and deposits in the area have been comprehensively analyzed,and the Gulabut Tolgoi gold deposit is considered to be a Paleo-Asian ocean that closed in the Triassic period and developed Paleogene from the end of the Carboniferous to Triassic In response to the large scale metallogenic events in Asia,the type of deposit should be a ductile shear zone gold deposit superimposed on granite.