甘肃省肃南县大柳沟铜多金属矿地质特征

Geological Characteristics of Daliugou Copper Polymetallic Deposit,Sunan County,Gansu Province

勘查区位于祁连山褶皱系北祁连褶皱带的西段、北祁连沟弧盆系中元古界镜铁山-朱龙关裂谷带中,在小柳沟钨钼多金属成矿带的东部。勘查区赋矿层位为青白口系龚岔群,含矿岩性为大理岩及铁质板岩。铁矿以赤铁矿化为主,呈块状、层状。主要铁矿物为赤铁矿,次为褐铁矿和菱铁矿,脉石矿物主要有石英、铁白云石和板岩。矿体品位28.02×10^-2~33.08×10^-2,真厚度0.87~6.67 m,控制长度约570 m。矿化受层位控制明显。铜矿化以孔雀石化为主,呈浸染状、薄膜状及脉状大理岩沿裂隙面分布,见少量辉铜矿。矿化受构造控制。根据含矿层位、含矿岩性和矿体特征,初步认为铁矿成因类型为沉积变质型铁矿床,矿床受层位控制明显,并在一定程度上受后期断层的改造;铜矿成因类型属变质岩型铜矿。

The exploration area is located in the western part of the North Qilian fold belt of the Qilianshan fold system and the Middle Proterozoic Jingtieshan Zhulongguan rift belt of the North Qiliangou arc basin system,in the east of Xiaoliugou tungsten molybdenum polymetallic metallogenic belt.The ore bearing strata in the exploration area are gongcha group of Qingbaikou system,and the ore bearing lithology is marble and iron slate.The iron ore is mainly hematite,which is massive and layered.The main iron minerals are hematite,followed by limonite and siderite.The gangue minerals are mainly quartz,ferruginous dolomite and slate.The ore body grade is 28.02×10^-2~33.08×10^-2,the true thickness is 0.87~6.67 m,and the control length is about 570 m.Mineralization is obviously controlled by horizon.The copper mineralization is dominated by malachite,disseminated,filmy and veined marble distributed along the fracture surface,with a small amount of chalcocite.Mineralization is controlled by structure.According to the ore bearing horizon,ore bearing lithology and ore body characteristics,it is preliminarily considered that the genetic type of iron ore is sedimentary metamorphic type,the deposit is obviously controlled by the horizon,and to some extent,it is reformed by the later faults;the genetic type of copper deposit belongs to metamorphic type.