摘要
塔乌尔别克金矿床位于西天山吐拉苏火山-沉积盆地,浅成低温热液金矿化及相关蚀变发育于下石炭统大哈拉军山组火山岩中,受近NNW-SSE或N-S向断裂及其交汇部位控制。本文对塔乌尔别克金矿床成矿早期(NW走向)和成矿晚期(NE走向)两期方解石脉进行了稀土元素组成和C-O同位素地球化学研究,以期揭示其流体演化与物质来源。结果表明,成矿早期方解石δEu值为1.09~4.74,δCe值为0.76~0.94,显示Eu正异常,Ce轻微负异常;而成矿晚期方解石δEu为0.73~0.85,δCe为0.82~0.95,显示Eu负异常,Ce负异常不明显;这表明成矿流体从早期的相对氧化状态逐渐演化至晚期的相对还原状态。成矿早期方解石的δ^(13)C_(V-PDB)介于0.2‰~1.8‰,δ^(18)O_(V-SMOW)介于12.1‰~15.3‰,指示其成矿流体主要来源于碳酸盐岩的溶解作用,且δ^(18)O_(V-SMOW)变化范围较宽,反映了大气降水的混入;晚期方解石δ^(13)C_(V-PDB)介于-0.1‰~1‰,δ^(18)O_(V-SMOW)介于9.2‰~9.9‰,表明其成矿流体主要由岩浆结晶分异作用产生。结合前人研究成果,本文认为,塔乌尔别克金矿床成矿早期的氧化性流体有利于金的富集与沉淀,成矿晚期还原性环境导致金沉淀效率大大降低。
The Tawuerbieke gold deposit is located in the Tulasu volcanic-sedimentary basin of the Western Tianshan.The epithermal gold mineralization and associated alteration are developed in the volcanic rocks of the Early Carboniferous Dahalajunshan Formation,controlled by NNW-and N-trending faults and their intersections.This paper investigates rare earth element(REE)compositions and C-O isotopic geochemistry of early-stage(NW-trending)and late-stage(NE-trending)calcite veins in the Tawuerbieke gold deposit to elucidate the fluid evolution and the sources of ore-forming materials.The results show that the early-stage calcite hasδEu andδCe values rang-ing from 1.09 to 4.74 and from 0.76 to 0.94,respectively,displaying positive Eu anomalies and slightly negative Ce anomalies.In contrast,the late-stage calcite hasδEu values of 0.73-0.85 andδCe values of 0.82-0.95,showing negative Eu anomalies and slightly negative Ce anomalies.This indicates that the ore-forming fluids evolved from a relatively oxidized state in the early stage to a relatively reduced state in the late stage.The early-stage calcite hasδ^(13)C_(V-PDB) andδ^(18)O_(V-SMOW) values ranging from 0.2‰to 1.8‰and from 12.1‰to 15.3‰,respectively,suggesting a source of carbonate dissolution.The late-stage calcite hasδ^(13)C_(V-PDB) values of-0.1‰to 1‰andδ^(18)O_(V-SMOW) values of 9.2‰to 9.9‰,indicating magmatic crystallization differentiation.Combined with previous studies,we propose that the oxidized fluids in the early stage of the Tawuerbieke gold deposit facilitated the enrichment and precipitation of gold,while the reduced environment in the late stage significantly decreased the efficiency of gold precipitation.
作者
王秋蕴
赵伟策
赵晓波
时一苇
刘洋涛
WANG Qiuyun;ZHAO Weice;ZHAO Xiaobo;SHI Yiwei;LIU Yangtao(School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China;Beijing Institute of Geology for Mineral Resources Co.,Ltd.,Beijing 100012,China;Xinjiang Natural Resources and Ecological Environment Research Center,)
出处
《矿产勘查》
2025年第5期1054-1064,共11页
Mineral Exploration
基金
新疆维吾尔自治区重点研发计划项目(2024B03005)资助。
