河北石湖金矿床控矿构造特征及矿体定位机制研究——以101脉为例

Characteristics of Ore-controlling Structures and Ore Emplacement Mechanism in the Shihu Gold Deposit, Hebei Province—A Case Study of the No.101 Vein

石湖金矿床位于太行山中北段,矿床产出严格受断裂构造控制。在详细野外观察及室内综合研究基础上,结合矿山生产地质资料的二次开发,认为石湖金矿控矿构造是在前中生代近SN向和NW向剪节理基础上,经燕山期构造追踪、叠加、复合而成。在主成矿期NNW-SSE向左行走滑应力作用下,石湖金矿区101脉控矿构造NW向部位以早期充填的石英闪长玢岩脉顶底板为薄弱面相对扩容,相应地矿床围岩蚀变带变宽、矿化强度高、矿化类型以石英脉型为主,形成局部"富矿柱";而近SN向部位则相对空间压缩,相应地围岩蚀变带变窄、矿化强度低、矿化类型以蚀变岩型为主,不利于成矿;富矿柱以高角度(约70°)侧列式分布,各富矿柱联合形成总体以40°向南侧伏的假象。根据该构造控矿规律,预测石湖金矿101脉47~61勘探线间、标高150 m以下部位为有利成矿部位,该成果已为矿山生产所证实。

The Shihu gold deposit lies in the middle-northern Taihang Mountains and is strictly controlled by faults.Theore-controlling structures in the mining district are not well-documented.Detailed field observation and laboratoryinvestigation of the No.101vein indicated that the ore-controlling structures of the Shihu gold deposit are thepre-Mesozoic shear joints with SN and NW strike that reactivated during the Yanshanian emerged from.The NNW-SSEleft-strike-slip stresses during the main mineralization stage led to the dilation of the NW-strike structural segmentsalong the roof and footwall of the early quartz diorite porphyrite veins,which contributed to the extensive wall-rockalteration,intensive gold mineralization and occur as quartz-vein type ores,and consequently the formation of rich orepillars.On the contrary,the SN-strike compressive structures correspond to the weak wall-rock alteration and goldmineralization and occur as altered-rock type ores.All the rich ore pillars laterally distributed with high-angle(70o±),and wholly pitched southward with40o angle.According to the structural ore-controlling regularities,the locationbetween the No.47and the No.61exploratory line with elevation below150m is an excellent ore-prospecting area.Ourprospecting proposal based on the ore-controlling structural analyses in the study area has been proven by theunderground works in the Shihu gold deposit.