山东招远大尹格庄金矿控矿构造解析与找矿预测

Analysis on the ore-controlling structures and prospecting in the Dayingezhuang gold deposit,Zhaoyuan,Shandong Province

【研究目的】大尹格庄金矿探明(金:283 t,银:397 t)发育于招平断裂带中段,矿区较大的断裂构造有4条:招平断裂、大尹格庄断裂、南周家断裂与南沟断裂,招平断裂带在矿区内呈NNE20°方向延伸,控制金矿体的形态、产状及发育部位。确定断裂构造的运动方向,可以指导大尹格庄金矿外围找矿预测。【研究方法】本文运用构造解析方法,分析了主要断裂构造的运动学特征。大尹格庄断裂、南周家断裂与南沟断裂为成矿后断裂,走向NWW向,倾向NNE,该3条断裂对招平断裂起错动与改造作用,在矿区范围内把招平断裂分割成4段。同样大尹格庄断裂把金矿体切割成两部分,南侧为1号矿体,北侧为2号矿体,在平面上1、2号矿体相距300~500 m,向下部由于矿体产状逐渐变缓,两者水平距离逐渐变大,这说明成矿后断裂为正断层。【研究结果】致使后期断裂北侧的矿体向下运动,也是导致矿体向北东方向侧伏的重要因素之一。【结论】由于南周家断裂与大尹格庄断裂的性质相似,可以推测南周家断裂北侧是重要的找矿靶区。随深度增加,招平断裂下盘的次级断裂构造逐渐发育,平面上表现为与主断裂呈10°~20°的交角,剖面上与主断裂倾向相近,而产状较陡,达45°以上,控制较小的金矿体发育,但品位较高,是大尹格庄金矿下一步找矿的方向。

[Objective]The Dayingezhuang gold deposit(explored Au 283 t,Ag 397 t)is located in the middle of Zhaoping fault zone which consist of the Zhaoping,Dayingezhuang,Nanzhoujia,and Nangou faults.The NEE-striking(20°)Zhaoping fault controls the location and shape of the orebodies.Determining the movement direction of faults can guide the prospecting prediction of Dayingezhuang gold deposit.[Methods]In this paper,the kinematic characteristics of main faults are studied by structural analysis method.The Dayinggezhuang,Nanzhoujia,and Nangou faults are post-ore faults and crosscut the Zhaoping fault into four segments.These three faults are NWW-striking,NEE-dipping.The Dayinggezhuang fault crosscut the orebody into two segments.No I orebody in the north and No II orebody in the south are separated by the Dayinggezhuang fault.In the plan view,the distance of the two orebodies is 300-500 m.In the profile,the orebody has a gentle dip and the distance of the two orebodies increase which suggest that the Dayinggezhuang fault is a normal fault.[Results]Owing to the up-to-the down movement,the orebody fall into NE-orientation.[Conclusions]In the light of the similar kinematics between the Dayinggezhuang and Nanzhou faults,we infer the northern of the Nanzhou fault is a beneficial prospecting target.With increasing of depth,the secondary faults develop and control the small gold ore shoot.In the plan view,these secondary faults intersect with the main fault at the angle of 10°-20°.In the profile,these secondary faults parallel with the main fault and have a middle steeply-dipping at 45o.These faults also are beneficial prospecting target.