白银市驴耳朵山金矿地质特征及成因初探

驴耳朵山金矿所处大地构造位置属北祁连加里东褶皱带东段,赋矿地层为前志留系第六岩组下部第2层含炭质千枚岩与细碧岩或细碧凝灰岩接触带的石英脉。区内北西向断裂构造既是导矿构造也是容矿构造。金矿体呈似层状或脉状,沿走向及倾向具有尖灭再现特征,赋矿岩石为含金属硫化物石英脉。矿体在地表不连续,但在深部沿脉坑道中连续性较好,沿走向厚度变化不大,且沿倾向厚度呈明显变厚趋势;品位自地表向深部也呈变富趋势。矿石矿物主要为黄铁矿、闪锌矿。本文通过对矿体赋存规律、矿化特征及岩石含金量等特征分析,认为驴耳朵山金矿受岩性和脆性-韧性断裂控制,属区域变质中温热液充填型金矿。

Geological Characteristics and Genesis of the Lverduoshan Gold Mine in Baiyin

The tectonic position of the the Lverduoshan gold mine is in the eastern section of North Qilian Caledonian fold belt.The ore-bearing stratum is quartz veins in the contact zone between the second layer carbonaceous phyllite and spilite or spilite tuff,in the lower part of the sixth group in the former Silurian.The north-west trending fault in the region is the ore-structure but also the host structures.Gold mine takes the shape of stratiform or vein-like,with wedging out recapitulation feature along the strike and dip,and the ore-bearing rock is metal sulfide quartz veins.The orebody at the surface is not continuous,but better continuity in the deep trenches along veins exists with small thickness variation along strike,but thickening trend exists along the tendency thickness.Ore grade exhibits rich trend from the surface to the deep.The ore minerals are pyrite,sphalerite.Based on features of the ore body,mineralization and gold bearing in rock and other analysis,it is believed that the Lverduoshan gold mine is controlled by lithology and brittle /ductile fracture,belonging to the regional metamorphism meso-hydrothermal fluid-filled gold mine.