山东蓬莱黑岚沟金矿区控矿构造研究与找矿预测

Ore-controlling Structure and Ore-prospecting Prediction of Heilangou Gold Deposit in Penglai District,Shandong Province

黑岚沟金矿区位于蓬莱市东南部,为蓬莱栖霞金矿带的北段,矿区内矿脉数量较多,多为石英脉型金矿体,中浅部品位相对较高。矿区范围内控矿断裂构造发育,走向以NNE、NE向为主,倾向为SEE和SE向,少量走向为NEE向,倾向SSE向。规模较大的控矿断裂多为NNE向与NE向断裂构造复合而成,在空间上主要表现为呈近平行等距分布,主控矿断裂的上下盘局部发育分支断裂,其控制分支矿脉的生成与富集。断裂构造的力学性质不同,控制的矿体形态也不一样。NNE向控矿断裂为右行剪切构造,控制的矿体延伸较长,厚度较窄。NE向断裂为张性构造,控制的矿体延伸较短,厚度相对较大。该矿区发育的多个金矿脉都由同一构造应力场作用下形成的,不同延伸方向、不同力学性质的断裂构造控制,是同一次大规模成矿作用的结果。在系统总结黑岚沟金矿区构造控矿规律的基础上,初步建立了构造控矿模式,提出了下一步的找矿预测方向。

The Heilangou gold deposit is located in the southeast of the Penglai district,which is one of the largest gold deposit in the northern part of the Penglai-Qixia gold belt.There are many lodes in this mining area,most of them are gold-bearing quartz veins with relatively high grade of gold in shallow levels.The ore-controlling faults in the mining area are developed,which mainly consist of NNE and NE-trending faults with a few NEE-trending faults.The NNE,NE and NEE-striking faults tend to SSE,SE and SEE,respectively.The large-scale ore-controlling faults are the compositions of the NNE and NE-trending faults,which present approximately parallel and equidistant distribution in space,and play a significant role in controlling the formation and enrichment of the branching gold lodes.The mechanical properties of the fault structure are different,therefore the shapes of the ore bodies are diverse.The NNE-trending ore-controlling faults are dextral shear structures,and the ore-bodies controlled by them are longer in length and narrower in thickness than those controlled by the NE-trending faults that are tensional structures.Many gold veins developed in this area are almost formed under the action of the same tectonic stress field,and are controlled by the fracture structures with different extension directions and mechanical properties.The formation of these gold lodes is a result of the same large-scale mineralization event.Based on the systematic summary of the structural ore-controlling regularities in Heilangou gold mining area,a ore-controlling model of structure is preliminarily established,and the prediction direction of prospecting is put forward.