图古日格金矿床方解石C、O同位素特征及其意义  

Carbon and Oxygen Isotopic Compositions of Hydrothermal Calcites fromTugurige Deposit and Their Significances

作　　者：刘琦 丁成武 戴盼 赵彬朝 王路远 Liu Qi;Ding Chengwu;Dai Pan;Zhao Binchao;Wang Luyuan(School of Resources and Environmental Engineering,Shandong University of Technology,Zibo 255000,Shandong,China)

机构地区：[1]山东理工大学资源与环境工程学院,山东淄博255000

出　　处：《吉林大学学报(地球科学版)》2025年第2期450-462,共13页Journal of Jilin University:Earth Science Edition

基　　金：国家自然科学基金青年科学基金项目(42002099)。

摘　　要：图古日格金矿床地处兴蒙造山带西段宝音图隆起区域。为了查明图古日格金矿床的成矿流体来源,本次对矿床的碳氧同位素进行了系统研究。测试结果显示:Ⅱ阶段青色方解石的碳同位素δ^(13) C_(V-PDB)平均值为-8.85‰,氧同位素δ^(18) O_(V-SMOW)平均值为11.65‰;Ⅲ阶段土黄色方解石的碳同位素δ^(13) C_(V-PDB)平均值为-6.78‰,氧同位素δ^(18) O_(V-SMOW)平均值为20.98‰,显示出由贫到富的δ^(13) C和δ^(18) O的变化趋势,反映了所分析的方解石是两个成矿阶段的产物。在前人研究的基础上,本文认为矿床形成的不同阶段中成矿流体的来源和组成有所差异,Ⅱ阶段成矿流体主要来自深部岩浆水,Ⅲ阶段成矿流体为来自岩浆水的热液流体与围岩发生了同位素的交换。通过对比宝音图群与区域地层的C-O同位素组成,发现宝音图群具有明显亏损氧同位素的特征,也指示成矿过程中热液流体与围岩发生了水岩反应。根据水岩反应理论模拟可知,成矿流体的可溶性碳主要以HCO_(3)^(-)的形式存在。同时,成矿流体δ^(13) C、δ^(18) O值分别为-9.2‰,8‰,表明Ⅲ阶段初始流体来源于岩浆,演化过程中与围岩中的海相碳酸盐岩发生水岩反应。结合矿床地质、矿物共生组合以及成矿流体特征等方面,认为图古日格金矿床具有典型的岩浆热液型金矿床的特征。The Tugurige gold deposit is a large-scale gold deposit which is located in the Xing’an-Mongolia Orgenic Belt(XMOB).In order to investigate the source of its ore-forming fluids,a systematic study of the carbon and oxygen isotopes of the deposit was conducted.Results show that the average carbon isotopeδ^(13) C_(V-PDB) value of the green calcite is-8.85‰,while the average oxygen isotopeδ^(18) O_(V-SMOW) value is 11.65‰.The trends inδ^(13) C andδ^(18) O reflect a transformation of calcite from low to high enrichment levels,indicating two distinct mineralization stages.On the basis of previous research,this study proposes that the origin and composition of ore-forming fluids differ across these stages of mineral deposit formation:In the stageⅡ,the ore-forming fluids mainly originated from deep-seated magmatic water,whereas in the stageⅢ,seawater-derived carbonates were mixed.Comparing the C-O isotope compositions between the Baoyintu Group and regional formations revealed significantly depleted oxygen isotopes,indicating water-rock interactions during the ore-forming process.Simulations of water-rock reactions indicate that soluble carbon in the ore-forming fluids mainly existed in the form of HCO_(3)^(-).The simultaneousδ^(13) C andδ^(18) O values of the ore-forming fluid,-9.2‰and 8‰respectively,imply that the initial fluid originated from magma and subsequently interacted with marine carbonate rocks in the surrounding rocks during the evolution process.Comprehensive research on the Tugurige gold deposit highlights it typical characteristics of a magmatic hydrothermal gold deposit,with geological features,mineral symbiosis,and fluid characteristics all indicating a close relationship with magmatic hydrothermal activity.

关 键 词：图古日格金矿床 方解石 碳氧同位素 成矿流体 岩浆热液型金矿床 

分 类 号：P571[天文地球—矿物学] P597[天文地球—地质学]