云南省保山市西邑大型铅锌隐伏矿床找矿预测地质模型

Metallogenic Prognosis Model of Xiyi Large Hidden Lead-Zinc Deposit in Baoshan in Western Yunnan Province

云南省保山市西邑铅锌矿床位于保山地块中北部,矿体主要赋存于下石炭统香山组构造破碎带中。应用"三位一体"勘查区找矿预测理论和方法,对保山西邑铅锌矿床开展了系统解剖,研究认为其成因类型为海底喷气沉积型(SEDEX型)+热液叠加改造型,成矿地质体为晚古生代(泥盆纪—早石炭世)保山盆地边缘的次级碎屑岩-碳酸盐岩沉积盆地,重磁推断矿区深部存在隐伏花岗岩体,对矿床形成产生了热液叠加改造;北东向或近南北向区域断层控制了沉积盆地的展布,其旁侧次级断层和断层破碎带为主要赋矿构造,矿体顶板主要为炭质泥岩、炭质板岩,含矿岩性为碳酸盐岩,显示硅钙面特征;成矿作用特征标志为矿化蚀变分带规律、北东(北西)侧伏规律;据此建立了地层+构造+硅钙面+蚀变分带组合"三位一体"找矿预测地质模型。利用该研究成果,在外围鲁图、广邑等地预测了有利成矿地段并提出勘查工作部署建议,其中鲁图和广邑预测区新发现了铅锌矿(化)体。

Xiyi Pb-Zn deposit is located in the middle-north section of Baoshan block.The orebodies are mainly hosted in the Lower Carboniferous calcareous rocks of Xiangshan Formation.By using metallogenic prognosis theories and methods in the exploration area,Xiyi large scale hidden lead-zinc deposit was systematicly studied.The deposit genesis is of submarine exhalative sedimentary(SEDEX-type)with hydrothermal superimposion.The metallogenic geological bodies are secondary clastic and carbonate sedimentary rocks in the edge of Baoshan basin,which are superimposed by the Late Paleozoic(Devonian and Early Carboniferous)concealed magmatic rocks.The metallogenic structures are NE or concealed faults and fault fracture zone;the metallogenic structural planes are lithologic interfaces and siliceous-calcium interfaces.The characteristic indicator of mineralization is characterized by mineralization and alteration zoning,and the orebodies exend laterally in NE or NW direction.On these bases,the metallogenic prediction model of stratum+structure+siliceous-calcium interface+mineralization and alteration zoning is established.By using this prediction model,we deliniated the favorable metallogenic areas and suggested the exploration work in the peripheral area of Lutu and Guangyi,where Pb-Zn ore bodies were found.