北大城地区韧性剪切带特征及金矿化

北大城金矿是受韧性剪切带控制的小型金矿。韧性剪切带分布在北大城—马鹿沟一带,总体呈北东东—近东西向展布,发育于太古宙建平群小塔子沟组的区域变质岩中。韧性剪切带早期以韧性剪切为主,晚期以脆性变形为主。韧性剪切带内由初糜棱岩、糜棱岩,超糜棱岩组成。宏观微观构造明显。金矿化带分布在韧性剪切带内的晚期断裂构造中,为石英脉型和蚀变岩型。

THE DUCTILE SHEAR ZONE FEATURES AND GOLD MINERALIZATION IN BEIDACHENG AREA, INNER MONGOLIA

Beidacheng gold deposit contrelled by a ductile shear zone is a small one in scale. The ductile shear zone distributes from Beidacheng to Malugcu, Inner Mongolia with NEE-near EW extension, occurs in the regional metamorphic rocks of Xiaotazigou Formation, Jianping Group, Archean, and is composed of a series of mylonitcs. The structure features of the ductile shear zone in the carly stage is mainly the ductile shear, but in the late stage is mainly brittle shear, and the macro-and/or micro-structures are obvious. The gold mineralization belt distributing in the late fractures of the ductile shear zone is of quartz vein and altered rock types.