摘要
东昆仑成矿带为青藏高原北部重要的稀贵金属成矿带,被誉为我国重要的“金腰带”,已经发现金矿床(点)约169处,主要集中在五龙沟、沟里和大场金矿集区。近几年的勘查找矿工作在主力矿区(五龙沟、沟里矿集区)外围有重大突破,显示其深部及外围金资源潜力巨大,亟需进一步加深对其金成矿背景、成矿模式、成矿规律的研究。东昆仑成矿带金矿床与区域广泛分布的岩浆岩显示密切的空间关系,但目前缺乏系统性探究并总结金矿化与岩浆作用的成因关系。本文在详细描述沟里和五龙沟矿集区金矿床成矿特征基础上,总结了热液独居石原位U-Pb定年结果,精确限定阿斯哈、岩金沟、红旗沟和黄龙沟金矿成矿年龄分别为227.1±6.5Ma、237.3±3.0Ma、236.7±3.7Ma和422.2±2.4Ma,表明存在志留纪-泥盆纪和三叠纪两期金矿化作用,并以三叠纪最为强烈。金矿床中均发育不同世代黄铁矿,其结构和化学成分分析表明多阶段的成矿流体演化。黄铁矿硫同位素和特征微量元素比值研究表明,东昆仑成矿带沟里矿集区和五龙沟矿集区金矿床成矿流体均与同时代岩浆活动有关,岩浆热液在不同金矿床中贡献程度不同。东昆仑成矿带岩浆岩主要形成于志留纪-泥盆纪(440~390Ma)和三叠纪(260~210Ma),与金矿化时间一致,显示出密切的成因关系,成矿流体主要来源于同时期长英质岩浆流体出溶。两期成矿-岩浆作用分别对应原特提斯洋和古特提斯洋俯冲-碰撞-板块回撤-断离等构造演化背景,在五龙沟和沟里地区形成典型的构造-岩浆-金成矿体系。
The East Kunlun is an important rare-precious-metal metallogenic belt in the northern part of the Qinghai-Tibet Plateau,known as the important“gold belt”in China.About 169 gold deposits(points)have been discovered,mainly distributed in the Wulonggou,Gouli and Dachang goldfields.In recent years,there have been significant breakthroughs in exploration outside the main mining areas(Wulonggou and Gouli goldfields),indicating that there is a huge potential for deep and peripheral gold resources.It is urgent for further research on the gold metallogenic background,model and regularity.The gold deposits in the East Kunlun metallogenic belt show a close temporal relationship with widely distributed magmatic rocks,but there is currently a lack of systematic investigation and summary of the genetic relationship between gold mineralization and magmatism.Based on a detailed description of the mineralization characteristics of gold deposits in the Gouli and Wulonggou goldfields,this article summarizes the in-situ U-Pb dating results of hydrothermal monazite,accurately defining the mineralization ages of the Asiha,Yanjingou,Hongqigou and Huanglonggou gold deposits at 227.1±6.5Ma,237.3±3.0Ma,236.7±3.7Ma and 422.2±2.4Ma,respectively.It indicates that there were two periods of gold mineralization,Silurian-Devonian and Triassic,with the most intense mineralization occurring during Triassic.Multiple generations of pyrite are developed in each gold deposit,and their structural and compositional analyses indicate multi-stage evolution of ore-forming fluids.Sulfur isotopes and trace elements of pyrite indicate that the ore-forming fluids in Gouli and Wulonggou goldfields are related to contemporaneous magmatic activity,and the contribution of magmatic-hydrothermal fluids varies among different gold deposits.The magmatic rocks in East Kunlun were mainly formed during the Silurian-Devonian(440~390Ma)and Triassic(260~210Ma),consistent with the timing of gold mineralization,suggesting a close genetic relationship.The ore-forming fluids mainly originated from contemporaneous felsic magmatic fluid exsolution.The two periods of gold mineralization and magmatism correspond to the tectonic evolution of Proto-Tethys Ocean and Paleo-Tethys Ocean,i.e.,subduction,collision,plate roll-back and break-off,forming a typical tectonic-magmatic-gold mineralization system in the Wulonggou and Gouli regions.
作者
李兴辉
梁改忠
吴金检
杨奎锋
范宏瑞
曾庆栋
张哲铭
胡芳芳
LI XingHui;LIANG GaiZhong;WU JinJian;YANG KuiFeng;FAN HongRui;ZENG QingDong;ZHANG ZheMing;HU FangFang(State Key Laboratory of Lithospheric and Environmental Coevolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《岩石学报》
北大核心
2025年第2期526-543,共18页
Acta Petrologica Sinica
基金
第二次青藏高原综合科学考察研究(2019QZKK0801)资助.
关键词
金矿床
岩浆作用
成矿年龄
成矿流体
东昆仑
Gold deposit
Magmatism
Mineralization age
Ore-forming fluid
East Kunlun
