摘要
抱伦金矿位于海南岛西南部的尖峰岩体外接触带,是目前海南岛储量最大的高品位金矿床。针对抱伦金矿成矿时代和成因机制尚不明确的问题,选取抱伦金矿床的辉钼矿样品进行Re-Os同位素定年研究。结果表明:辉钼矿Re-Os模式年龄为(223.8~227.4)Ma,^(187)Re-^(187)Os等时线年龄为(224.6±7.2)Ma,表明成矿作用发生在印支期,与海南岛印支期构造、岩浆和变质作用时限相符,确定抱伦金矿为典型造山型金矿;印支期区域变质作用和岩浆活动为抱伦金矿提供了成矿流体,而区域性挤压—伸展构造转换为成矿作用提供了重要的成矿通道和空间。研究结果深化了对海南岛金矿成矿地质背景的理解,并为类似复杂构造环境下的造山型金矿找矿提供了参考模型。
Hainan Island,located in the southern region of the South China Block,has experienced a complex tectonic evolution,notably influenced by the Triassic Indosinian orogeny,characterized by terrane collisions,magmatism,and metamorphism.Within this geological context,the Baolun gold deposit,situated in the exocontact zone of the Jianfeng granitic intrusion in southwestern Hainan and recognized as the island’s largest high-grade gold resource,has presented longstanding questions concerning its metallogenic age and genesis.To resolve these uncertainties,Re-Os isotopic dating of molybdenite extracted from auriferous quartz veins has been conducted,yielding model ages ranging from 223.8 to 227.4 Ma and an isochron age of(224.6±7.2)Ma.These results definitively constrain the mineralization to the Late Triassic Indosinian epoch,aligning it temporally with regional tectonic,magmatic,and metamorphic activities.The deposit exhibits characteristics typical of orogenic gold systems,including a compressional tectonic setting,control by crustal-scale faults,and quartz-sulfide vein mineralization.Fluid generation is attributed to devolatilization processes during Indosinian metamorphism,with additional magmatic contributions from the Jianfeng intrusion.Structural transitions from compression to extension facilitated fluid migration along shear zones and faults,ultimately leading to ore deposition.These findings not only confirm Baolun as a definitive orogenic gold deposit but also underscore the exploration potential in similar tectonic settings across Hainan.This study provides a genetic model that integrates metamorphic,magmatic,and structural controls,offering a framework for targeting such deposits in complex orogenic terranes.
作者
蔡霖
许德如
单强
苏伟政
CAI Lin;XU Deru;SHAN Qiang;SU Weizheng(East China University of Technology,Nanchang 330013,Jiangxi,China;CAS Key Laboratory of Mineralogy and Metallogeny,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;National Key Laboratory of Uranium Resources Exploration-Mining and Nuclear Remote Sensing,East China University of Technology,Nanchang 330013,Jiangxi,China)
出处
《黄金科学技术》
北大核心
2025年第4期683-695,共13页
Gold Science and Technology
基金
国家自然科学基金重点项目“江南古陆金(多金属)大规模成矿的机理研究”(编号:41930428)资助。
