基于地球化学数据的斑岩型矿床蚀变矿物提取与综合成矿预测  

Alteration mineral identification and metallogenic prediction of porphyry deposits based on geochemical data

作　　者：张维康 张青 张成 高征西 许立权 曹磊 李奥冰 姜春伟 ZHANG Weikang;ZHANG Qing;ZHANG Cheng;GAO Zhengxi;XU Liquan;CAO Lei;LI Aobing;JIANG Chunwei(Hubei Geological Survey,Wuhan 430034,China;Faculty of Earth Resources,China University of Geosciences(Wuhan),Wuhan 430074,China;Inner Mongolia Key Laboratory of Magmatic Mineralization and Ore-Prospecting,Huhhot 010020,China)

机构地区：[1]湖北省地质调查院,武汉430034 [2]中国地质大学(武汉)资源学院,武汉430074 [3]内蒙古自治区岩浆活动成矿与找矿重点实验室,呼和浩特010020

出　　处：《地质科技通报》2024年第5期105-116,共12页Bulletin of Geological Science and Technology

基　　金：内蒙古自然资源厅勘查处综合预算项目“内蒙古北山成矿带金铜矿成矿关键问题研究及找矿预测”;内蒙古自治区岩浆活动成矿与找矿重点实验室项目“内蒙古阿巴嘎旗北部银铅锌多金属矿成矿背景、机制及找矿方向”。

摘　　要：传统的勘查地球化学工作侧重于成矿元素异常的提取、解释和评价,忽略了与成矿作用相关的其他主、微量元素可能提供的找矿信息,无法有针对性地从地球化学数据中开展蚀变矿物提取并指导找矿。本研究以矿物学的角度从地球化学数据中提取蚀变矿物并对研究区进行了成矿预测,介绍了以地球化学数据为基础、以矿物化学式中不同元素间化学计量数比值为理论基础的蚀变矿物提取新方法——一般元素比分析法。基于北山造山带高石山地区1∶2.5万岩屑地球化学测量获得的地球化学数据研究表明,从SiO_(2)、Al_(2)O_(3)、Na_(2)O、K_(2)O等数据中可有效识别出与斑岩型矿床密切相关的绢云母、钾长石等蚀变矿物,其中绢云母沿岩体边缘分布,钾长石多集中分布于岩体的中心部位。综合提取出的蚀变矿物和岩浆岩、构造、传统化探异常等控矿因素和找矿信息,进一步对研究区开展了证据权重法成矿预测,共圈定靶区5处。本研究提取的蚀变信息在野外调查工作中得到了验证,表明一般元素比分析法提取蚀变矿物是可行的,可在传统成矿预测方法的基础上进一步提供关键找矿信息。[Objective]Traditional exploration and geochemical studies have primarily focused on the extraction,interpretation and evaluation of metallogenic element anomalies.This approach,however,overlooks valuable ore prospecting information,which may be provided by other major and trace elements.Consequently,altered minerals cannot be effectively extracted,and geochemical data is under utilized for ore prospecting.Therefore,the author extracts alteration minerals from a mineralogical perspective and make metallogenic prediction.[Methods]This paper introduces a new method for extracting alteration minerals based on geochemical data and the stoichiometric ratios of different elements in the mineral chemical formula,referred to as the general element ratio analysis.[Results]Based on geochemical data obtained from 1∶25000 debris geochemical survey in the Gaoshishan area of the Beishan orogenic belt,results show that sericite,K-feldspar and other alteration minerals are closely related to porphyry deposits,which can be effectively identified from SiO_(2),Al_(2)O_(3),Na_(2)O,K_(2)O and other data.The mapping results reveal that sericite is mostly distributed along the intrusion′s margins,while K-feldspar is mainly concentrated in the center of theintrusion.Then,based on the ore-controlling factors and ore-prospecting information,such as alteration minerals,magmatic rocks,structures,and traditional geochemical anomalies.This study further conducts metallogenic prediction for the Gaoshishan area using the weight-of-evidence method,delineating five target areas.[Conclusion]The alteration information extracted in this study has been validated through field investigations confirming that the proposed method is feasible and can provide critical prospecting insights beyond those offered by traditional metallogenic prediction methods.

关 键 词：一般元素比分析 蚀变矿物 成矿预测 斑岩型矿床 北山造山带 地球化学 

分 类 号：P618[天文地球—矿床学]