会泽超大型富锗银铅锌矿床矿化-蚀变分带规律及构造的控制作用

Mineralization-alteration zoning regularity and structural ore-controlling role in the Huize super-large sized Ge-Ag-rich Pb-Zn deposit, Yunnan Province

会泽超大型富锗银铅锌矿床是川—滇—黔铅锌多金属成矿区滇东北矿集区的典型代表。基于大量的地表调研和坑道精细编录,通过赋矿白云岩的岩石学、地球化学与矿化蚀变分带规律、构造对矿化-蚀变带控制作用的研究,认为赋矿粗晶白云岩是成矿过程中白云石化的产物,具有典型的热液蚀变成因,与沉积-成岩成因的摆佐组细晶白云岩、白云质灰岩明显不同;根据矿石和蚀变围岩中铅锌矿物组成与矿化、蚀变程度及其分布特征,该矿床矿化-蚀变分带规律:从矿体到围岩依次为铅锌矿石—铅锌矿化黄铁矿带→铅锌矿化/黄铁矿化粗晶白云岩带→灰白色粗晶白云岩带、米黄色粗晶白云岩带、肉红色粗晶白云岩带、网脉状白云石化灰岩带(蚀变残留体)、弱白云石化灰岩带。矿化-蚀变带明显受冲断褶皱构造(矿山厂、麒麟厂、银厂坡斜冲断层及其派生褶皱)上盘的层间断裂带控制,形成了典型的"成矿构造-蚀变白云岩-铅锌矿体"的矿化结构。该认识不仅丰富了会泽型(HZT)铅锌矿床成矿理论,而且对指导滇东北铅锌矿集区,乃至川滇黔成矿区的资源危机矿山的综合地质研究与找矿勘查具有重要的现实意义。

The Huize super-large sized Ge-Ag?rich Zn?Pb deposit is a typical deposit in the Sichuan?Yunnan?Guizhou lead-zinc polymetallic ore-forming area.On the basis of enormous field survey and tunnel measurements and through studies of petrology and geochemistry of ore-bearing dolomite,the authors investigated zonation regularity of mineralization and alteration and structural ore-controlling role,and the results show that ore-bearing dolomite was formed by dolomitization in the ore-forming process,characterized genetically by typical hydrothermal alteration.Its genetic type differs from that of fine-grained dolomite and dolomitic limestone in the Baizuo Formation.According to the mineral compositions of ores and altered wall rocks,the degree of mineralization and alteration and the distribution characteristics,the zoning regularity of mineralization and alteration has been revealed:from the orebody to the wall rock,there exists the zoning of Zn?Pb ores and Zn?Pb mineralized pyrite zone→Zn?Pb and pyrite?mineralized coarse?grained dolomite zone→gray coarse?grained dolomite zone,beige coarse?grained dolomite zone,flesh red coarse?grained dolomite zone,net veined dolomitized limestone zone,and weakly dolomitized limestone zone.Mineralization and alteration zoning is obviously controlled by interlayer faults on the upper wall of the thrust?fold structures(Kuangshanchang,Qilingchang,Yinchangpo oblique faults and its derivatives folds).On such a basis,the mineralization structure of ore-forming structure,altered dolomite and Zn-Pb orebody has been established.The results obtained by the authors not only enrich the metallogenic theory of the HZT?type Zn-Pb deposits but also have important practical significance for comprehensive geological study of the resources crisis mines in the northeastern Yunnan ore concentration area and the Sichuan?Yunnan-Guizhou metallogenic area.