甘肃白银厂铜多金属矿田地球化学场特征及信息提取  

Geochemical Field Characteristics and Information Extraction of the Baiyinchang Copper Polymetallic Ore Field in Gansu Province

作　　者：窦小雨 郭小刚 周宏[4] 王秦 苟瑞 郭东宝 DOU Xiaoyu;GUO Xiaogang;ZHOU Hong;WANG Qin;GOU Rui;GUO Dongbao(Gansu Provincial Geological Prospecting Fund Management Center,Lanzhou,Gansu 730000;Baiyin Mineral Exploration Institute of Gansu Nonferrous Metal Geological Exploration Bureau,Baiyin,Gansu 730900;Key Laboratory of Strategic Mineral Resources of the Upper Yellow River,Ministry of Natural Resources,Lanzhou,Gansu 730000;GansuNonferrous Metals Geological Exploration Bureau,Lanzhou,Gansu 730030)

机构地区：[1]甘肃省地质勘查基金管理中心,甘肃兰州730000 [2]甘肃省有色金属地质勘查局白银矿产勘查院,甘肃白银730900 [3]自然资源部黄河上游战略性矿产资源重点实验室,甘肃兰州730000 [4]甘肃省有色金属地质勘查局,甘肃兰州730030

出　　处：《地质与勘探》2022年第6期1139-1153,共15页Geology and Exploration

基　　金：中国地质调查局项目“甘肃省白银厂及外围铜多金属矿整装勘查区关键基础地质研究”(编号:12120114050101);甘肃省基础地质调查项目(编号:甘资勘函[2021]184-32)联合资助。

摘　　要：甘肃白银厂铜多金属硫化物矿田位于北祁连造山带东段,近年来面临严重的资源枯竭危险。通过对区内的构造地球化学测量数据进行多元统计、指数累加等方法的分析,进一步探讨了矿田内地球化学场分布特征,提取更多的找矿预测地球化学信息。研究发现矿田内主要的成矿元素分布受岩性及构造的双重控制,具有明显的北西向成带、北东向成串的特征,矿田中部和外围具有不同的地球化学异常场特征。构造地球化学测量的主要指示元素为Cu、Pb、Zn、Au、Ag、As、Sb、Hg、K、W等。根据地球化学场分布特征分析,认为拉牌沟地区赋矿酸性火山岩向北侧伏,其深部具有一定的找矿前景。基于特征因子得分推断出矿田内具有北东向、北北东向、北东东向、北西向4组规模较大的断裂构造21条,最晚期形成的北西向次级断裂F15~F21是主要的控矿构造。已知的古火山喷口位于W-Au-Mn-Fe-Ti-V-Ba-K-S因子得分小于-0.7的负异常中心内,据此厘定出11个中心喷发口和5个火山喷发中心,已知的矿床位于火山喷发中心内或各火山中心喷发口的结合部。本研究为该矿田开展找矿预测工作提供了有利的地球化学找矿信息。The Baiyinchang copper polymetallic sulfide ore field in Gansu Province is located in the east section of the North Qilian orogenic belt,which has faced a serious risk of resource depletion in recent years.This work conducted multivariate statistical analysis and index accumulation analysis of the tectono-geochemical survey data in this ore field to explore the geochemical field distribution,and extracted much reliable geochemical ore-prospecting information.Results show that the distribution of main ore-forming elements is jointly controlled by lithology and structures,and exhibits NW-trending zonation and NE-trending cluster distribution.This ore field displays distinctive geochemical anomaly field features between its central and periphery parts.The main indicator elements of tectono-geochemical survey are Cu,Pb,Zn,Au,Ag,As,Sb,Hg,K,W,etc.The distribution of the geochemical field indicated that the ore-bearing acid volcanic rocks in the Lapaigou area extend to the north and reveal some prospecting potential in the deep part.The score of characteristic factors suggests that 21 large fault structures were developed in four groups of NNE-,NNE-,NNE-and NW-trending in the ore field,and the NW-trending secondary faults F15~F21 formed in late stage are the main ore-controlling structures.The known ancient volcanic vents are located in the negative anomaly center with W-AU-Mn-Fe-Ti-V-Ba-K-S factor score less than-0.7.A total of 11 central eruption vents and five were thus inferred,and the known deposits are generally located in the volcanic eruption centers or at the junction of each central eruption vent.This study can provide favorable geochemical prospecting information for the next prospecting prediction in this ore field.

关 键 词：VHMS型矿床 构造地球化学 异常特征 推断解释 白银厂铜多金属矿田 甘肃省 

分 类 号：P618.41[天文地球—矿床学] P595[天文地球—地质学] P632.2