青海省曲麻莱县牙扎曲金矿床地质特征及成矿条件分析

Geological Features and Metallogenic Conditions of the Yazha Gold Deposit in Qinghai County,Qumalai Province

通过论述牙扎曲金矿床的地质背景,总结其地质特征,认为该区三叠纪巴颜喀拉山群清水河组泥质板岩、砂岩为含矿岩性,北西西向断裂对矿体的形成有控制作用。从探槽工程揭露情况看,矿区局部所形成的明显的黄褐色褐铁矿化、硅化、绿泥石化、绿帘石化等蚀变对金矿的形成十分有利,牙扎曲—折赛那久一带地层为泥、砂质碎屑岩夹少量细砾岩和碳酸盐岩,为一套前陆盆地中形成的浊流相复理石建造,发育不完整"鲍马序列",其中以含泥屑及含碳岩层含Au丰度高,具备成矿的地层、构造条件,构造蚀变岩型金矿潜力大。

After discussing the geological background of the Yazhaqu gold deposit and summarizingits geological characteristics, the author believes that the argillaceous slate and sandstone in Qingshuihe Formation of Triassic Bayanhar group serve as the ore-bearing rocks and the NWW fractures control the formation of this deposit. The exposed results of trench works show that the obvious tawny limonitization, silicification, chloritization and epidotization occurred in local min- ing area are beneficial to the formation of this gold deposit. The strata along Yazhaqu-Zhesainajiu area are composed of clay and sandy clastic rocks, mixing with a small amount of fine conglomerate and carbonate rock, which belongs to a set of turbidite facies flysch construction that formed in foreland basin. And the ＂ Bouma sequence＂ is not completely developed in these strata, in which the mud debris andcarbon-bearing rock layer contain abundance gold, with strata and tectonic conditions for mineralization. Thus, this area has great potential to prospect the tectonic al- tered rock type gold deposit.