陕南地区硝璜洞金矿地质特征及成因

陕南秦巴山区是我国重要的金矿产区，尤其是安康西北部的羊坪湾-流芳金成矿带更是秦巴山区的典型代表，硝璜洞金矿就位于这一成矿带上.硝璜洞金矿产于志留纪大贵坪组第一岩性段的含炭质云英片岩夹薄层炭质石英岩内，显示岩性对金矿化的制约.矿体严格受韧性剪切带控制，主要赋存于与主剪切带呈“入”字形相交的次级韧性断裂带中.矿体呈似层状、透镜状、脉状产出.金矿物以自然金形式赋存，自然金粒度呈粗粒、巨粒.野外可识别出3期硅化蚀变，金矿化与第1期蚀变关系密切.矿床成因为韧性剪切带控制的变质热液型金矿床.

GEOLOGY AND GENESIS OF THE XIAOHUANGDONG GOLD DEPOSIT IN SOUTHERN SHAANXI PROVINCE

The Qinling-Bashan Mountainous region is an important gold producing area in China,represented by the Yangpingwan-Liufang gold metallogenic belt in the northwest of Ankang,where the Xiaohuangdong gold deposit is located.The Xiaohuangdon gold deposit is hosted in the carbonaceous mica quartz schist with thin bedded carbonaceous quartzite of the first member of Silurian Daguiping formation,showing a lithological restriction.The orebodies,presented in layers,lens and veins,are controlled strictly by the ductile shear zone,dominantly occurring in the secondary ductile fractures which connect to the major shear zone.Native gold,as coarse and huge grains,is the main occurrence of the mineral.Three stages of silicification can be recognized in the field.The gold mineralization is closely related to the first stage of alteration.The deposit genetically belongs to ductile shear zone controlled metamorphic hydrothermal type.