投稿时间：2020-09-29
修订日期：2020-12-11
网络发布日期：2021-05-17
中文摘要:迪彦钦阿木矿床位于大兴安岭中段二连浩特-东乌旗多金属成矿带，是区内新近发现的一个超大型斑岩钼矿床。为了厘清蚀变矿物的成分对找矿的指示意义，文章运用电子探针和LA-ICP-MS对迪彦钦阿木矿床青磐岩化带绿帘石亚带的绿泥石和绿帘石的主微量元素成分进行了分析。电子探针数据表明，这些绿泥石属于铁斜绿泥石（辉绿泥石）。绿泥石四面体位置置换为AlⅣ对Si的替换，八面体位置置换以Fe-Mg相互置换为主；主量元素除Fe、Mg呈现此消彼长的变化外，其他元素含量变化不大。矿区绿帘石属于普通绿帘石亚族，由热液交代角闪石和斜长石等矿物形成，可分为脉状和浸染状绿帘石，其主量元素含量差别不大。LA-ICP-MS分析结果显示，靠近矿体中心的绿泥石具有较高的近端指示元素（Sc、Ti、V、Cr、Mn、Co、Cu、Ga、Sn、Ba）含量以及较高的Ti/Sr、Ti/Pb、V/Ni比值，而离矿体中心较远的绿泥石具有较高的远端指示元素（Li、Na、K、Ni、Sr）含量。绿帘石中成矿金属含量比较低，离矿体中心较远的绿帘石相对富集As、Sb、Pb等元素。此外，绿帘石中w（Cr）、w（Ti）和w（V）以及Ti/Sr和V/Ni的比值随矿体品位的升高而降低。研究表明，迪彦钦阿木矿床绿泥石中w（Ti）、w（V）和w（Ga）及Ti/Sr、Ti/Pb和V/Ni比值，以及绿帘石中w（As）、w（Sb）和w（Pb）具有指示矿化中心的作用，而绿帘石中w（Cr）、w（Ti）和w（V）以及Ti/Sr和V/Ni值可以作为寻找斑岩矿床富矿体的指标。迪彦钦阿木矿床中绿泥石和绿帘石的元素变化主要受流体成分、温度、硫逸度、矿物共生组合等因素影响。文章获得的认识或可应用于其他类似斑岩钼矿床（点）的找矿勘探中。
Abstract:Located in the central part of the Da Hinggan Mountains, the Diyanqinamu deposit is a giant porphyry Mo deposit. In order to clarify the significance of the composition of altered minerals for prospecting, the authors analyzed major and trace element compositions of epidote and chlorite from the epidote sub-zone of propylitic alteration in the Diyanqinamu deposit by electron microprobe analysis and LA-ICP-MS. The EPMA results show that the chlorite in the propylitic alteration zone can be categorized as diabantite. The replacement of Si by AlⅣ is the major substitution in the tetrahedral site, while in the octahedral site, Mg and Fe are mutually replaced. Except for Fe and Mg, the variations of major elements are not significant. The epidote belongs to pistacite, which is formed by hydrothermal replacement of amphibole and plagioclase and occurs either as veins or as disseminations in wall rocks, and there are no pronounced variations of the major elements. LA-ICP-MS analyses indicate that the proximal pathfinder elements (i.e., Sc, Ti, V, Cr, Mn, Co, Cu, Ga, Sn and Ba) and Ti/Sr, Ti/Pb and V/Ni ratios are high in chlorite near the orebody center. Distal pathfinder elements (i.e., Li, Na, K, Ni and Sr) are enriched in chlorite in more distal parts outside the center. Epidote contains relatively low content of metals of economic significance in Diyanqinamu, while epidote far from the center is characterized by higher content of As, Sb and Pb. The content of Cr, Ti and V, and ratios of Ti/Sr and V/Ni decrease with the decrease of ore grade. To sum up, the content of Ti, V and Ga, the Ti/Sr, Ti/Pb, V/Ni ratios of chlorite, and As, Pb and Sb of epidote in propylitic zone of the Diyanqinamu porphyry Mo deposit could serve as potential indicators of mineralization center, while the content of Cr, Ti, V and ratios of Ti/Sr, V/Ni in epidote could be indicators of fertile orebodies. The element content of chlorite and epidote in the Diyanqinamu deposit is mainly affected by fluid composition, temperature, sulfur fugacity and mineral assemblage. The present study could probably also be applied to other similar porphyry Mo systems, thus providing useful guidelines for further exploration.
文章编号：
中图分类号：
文献标志码：
基金项目:本文得到国家自然基金项目（编号：4167030375、42022021）和矿床地球化学国家重点实验开放基金（编号：201808）的共同资助
引用文本：
王帏,冷成彪,张兴春,田振东.2021.内蒙古迪彦钦阿木斑岩钼矿床绿泥石和绿帘石矿物化学特征及其成矿指示意义[J].矿床地质,40(2):241~261WANG Wei,LENG ChengBiao,ZHANG XingChun,TIAN ZhenDong.2021.Mineral chemistry of chlorite and epidote in Diyanqinamu porphyry Mo deposit of Inner Mongolia and its implication for exp[J].Mineral Deposits40(2):241~261
图/表
