西藏仁布念扎金矿矿床成因及找矿标志

Ore genesis and prospecting criteria of Nianzha gold deposit in Renbu County,Tibet

念扎金矿位于冈底斯铜(钼)成矿带南部,产于强片理化及褪色蚀变超基性岩片与燕山期石英闪长岩体的接触边部。矿体主要赋存于含矿构造带蚀变破碎带,多呈脉状产出,厚度较稳定且矿化较均匀,矿区内地质构造复杂,矿体空间展布及富化主要受控于NW向断裂,NE向断裂则主要为破矿构造,矿区内褐铁矿化、硅化、碳酸盐化与矿化呈正相关。本文通过对矿床成矿背景及成矿规律的总结,表明矿化主要受地层岩性(围岩)、构造及围岩蚀变控制,属于构造蚀变型金矿床,并提出各含矿带深部、倾向延伸部分及石英脉集中地段找矿潜力较大,可为相似成矿条件矿段的地质勘查工作提供理论指导。

Nianzha gold deposit is located in the southern Gangdise metallogenic belt,which outputted in the contact edge between strong schisteous-fade alteration ultramafic schist and Ynshanian quartz diorite rock mass.The gold ore-body is hosted by altered fracture zone of ore-bearing structure,which occurs as vein-like.Besides,the orebody characterized by relatively stable thickness and uniform mineralization.The Nianzha gold mining area is characterized by complex tectonic framework which the NW-trending fracture as the main ore-bearing structure,has the close relationship with mineralization,and the NE-trending structure is the ore-breaking structure.The limonitization,silicification,carbonation has positive correlation with mineralizaiton.According to the systematic summary of the geological background,strata,tectonic,rock mass and alteration characteristics,this paper concluded that the Nianzha gold deposit is a structurally-controlled-altered type gold deposit,which main controlled by formation lithology（surrounding rock）,tectonic and rock alteration.In addition,this research showed that the deep part of orebearing belt,extending part along the tendency and the quartz-vein concentrated section have the better prospecting potential,which could be the prospecting guideline in other area with the similar geological setting within the Nianzha mining area.