摘要:
西藏班戈日阿铜多金属矿床位于班戈-腾冲多金属成矿带,是近年来新发现的矽卡岩型铜多金属矿床,已探明资源量达中型规模。最新研究和找矿成果显示矿带呈北西向展布,受燕山晚期白垩纪花岗岩类岩体侵入作用控制,矿体分布于岩体与下白垩统灰岩地层接触带及附近部位。在空间上,矿床主要分为三个矿段:主矿体分布在矿区中西部,目前在西矿段已圈定5个(条)铜矿体,矿体呈似层状、透镜状,其中最大的Cu13号矿体长221 m,平均厚9 m,沿倾向已控制延深100 m以上,铜品位:0.45%~2.01%,平均0.9%。主要金属矿物为黄铜矿、磁铁矿。中矿段已经圈定3条矿体,成矿元素除铜外,铅、锌、银含量也较高,为铜多金属矿体。矿体呈似层状、透镜状。其中以Cu-23号矿体最大,长达300 m,矿体最宽处达110 m。矿体平均品位Cu1.48%,Pb 1.25%,Zn 2.52%,A g 32.52×1-0 6。本文在矿区地质特征研究的基础上,通过对1:5万水系沉积物测量成果分析,对比中、西矿段成矿条件,对矿区东段进行了预测评价,指出该矿区具有较好的铜多金属找矿前景。同时建议对已圈定的1:5万水系沉积物异常开展1:1万土壤地球化学测量工作,进而圈定该区铜多金属矿带或矿(化)体,为矿区深入勘查工作提供依据。
关键词:
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铜矿床
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地质特征
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找矿前景
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班戈日阿
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西藏
Abstract:
The Ri'a copper polymetallic deposit,which is located in Bange-Tengchong polymetallic mineralization belt,is a medium-sized copper deposit of skarn type discovered in recent years.The newest researches and prospecting achievements of this deposit show that the mineralized zone mainly spreads with an N-W trending and is controlled by intrusion of the Late Yanshanian Cretaceous granitoid pluton; the ore-bodies are mainly occurred in the contact zones between granitoid pluton and lower Cretaceous limestone and their adjacent positions.Spatially,the deposit can be divided into three ore blocks;the main ore body of the western ore block locates in the mid-west part of the deposit,where five copper ore-bodies have been delineated,mainly showing stratiform-like and lenticular shapes.The No.13 copper ore-body is the biggest one with length of 221 m,average thickness of 9 m and controlled depth of over 100 m in dip direction.The copper grade has a range of 0.45-2.01% with average of 0.9%,and the main metallic minerals are chalcopyrite and magnetite.In the middle ore block,where three ore-bodies have been delineated.The ore-forming element is mainly Cu,but the contents of Pb,Zn,and Ag are also relatively high,showing a copper polymetallic mineralization.The ore bodies are occurred in the form of stratiform-like and lenticular shapes,and the No.23 copper ore body is the biggest one with length of 300 m and maximum thickness about 110 m.The average grades of ore-body are as follows: Cu:1.48%,Pb:1.25%,Zn:2.52% and Ag:32.52×10-6.Based on the researches of geological characteristics of the deposit and the analysis of achievements of 1∶50000 scale stream sediment survey,as well as the correlation of the metallogenic conditions of the middle and western ore blocks,the prospecting potential in the eastern ore block of the deposit is evaluated and predicted in this paper.It is pointed out that the eastern ore block of the deposit has a better prospecting potential of copper polymetallic ore bodies.At the same time,it is suggested that 1∶10,000 soil geochemical survey works should be carried out in the area of anomalies delineated by 1∶50000 scale stream sediment survey to further delineate copper polymetallic ore belt or ore bodies for providing fundamental basis for further exploration works.
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