豫西张吉口银矿床地质特征及找矿前景

豫西小秦岭地区小河岩体南缘首次发现了张吉口银矿床,矿床类型为受断裂构造控制的中低温热液型脉状银矿床,研究银矿床地质特征、成矿规律对指导区域地质找矿工作具有重要意义。银矿体赋存于中元古界小河二长花岗岩体与中元古界官道口群接触带的F1断裂构造蚀变带中,矿体呈脉状,沿走向具分支复合现象。矿石自然类型为石英脉状—网脉状银矿石、浸染状银矿石。银主要赋存于独立银矿物辉银矿、硫锑铜银矿中,呈他形粒状,粒度较小,黝铜矿中的银以晶格银形式存在。围岩蚀变主要为硅化和绢云母化。断裂构造、蚀变矿化及化探异常为主要找矿标志。综合分析认为张吉口银矿体深部及走向两侧、司家路土壤化探异常区为主要找矿靶区。

Geological characteristics and prospecting potential of Zhangjiankou silver deposit in West Henan Province

The Zhangjiankou silver deposit was discovered for the first time in the southern margin of Xiaohe rock mass in the Xiaoqinling area, western Henan. The deposit type is a middle-low temperature hydrothermal veins-type vein-shaped silver deposit controlled by faulting structure. There is great significance of regional geological prospecting through research of geological characteristics of silver deposit. The silver orebodies occur in the F1 fault structural alteration zone in the contact zone between the Middle Proterozoic Xiaohezhang granite body and the Middle Proterozoic Guandaokou Group. The ore bodies are vein-shaped with branching and compounding along the strike. The natural type of ores is quartz veins - reticulate and disseminated silver ores. Silver mainly occurs in the independent silver mineral galena and sulfur antimony copper silver mineral which are granular with smaller particle size. Silver exists in tetrahedrite in form of silver crystal lattice. Wall rock alteration is mainly silicification and sericitization. Fault structure, alteration mineralization and geochemical anomaly as the main prospecting signs. Comprehensive analysis shows that the deep and the side of the Zhangjikou silver ore body is located. The abnormal area of soil geochemical exploration is the main prospecting potential area.