缅甸Wunto-Popa岩浆弧Shangalon铜金矿床辉钼矿Re-Os同位素测年及其地质意义
Re-Os isotope dating of molybdenite from Shangalon Cu-Au deposit in the Wunto-Popa magmatic arc,Myanmar and its geological significance
冷秋锋 1吴松洋 2刘书生 2聂飞 3张彬2
作者信息
- 1. 中国地质调查局成都地质调查中心(西南地质科技创新中心),四川 成都 610218;成都环境地质与资源开发研究所有限责任公司,四川 成都 610218
- 2. 中国地质调查局成都地质调查中心(西南地质科技创新中心),四川 成都 610218
- 3. 中国地质调查局应用地质调查中心,四川省 成都 610036
- 折叠
摘要
Shangalon铜金矿床位于缅甸Wunto-Popa岩浆弧北段,研究工作薄弱,其成矿地质背景和矿床成因尚缺乏高精度同位素成矿年代学数据的制约.本文选取典型矿石中 5件辉钼矿样品通过Re-Os同位素定年方法厘定成矿时代,获得的模式年龄集中变化于38.5±0.6至38.3±0.5 Ma,加权平均年龄为38.4±0.2 Ma,对应的等时线年龄为38.0±1.6 Ma(MSWD=0.17),二者在误差范围内基本保持一致,指示Shangalon铜金矿床的成矿时限为始新世,该年龄数据与矿区的含矿闪长岩和花岗闪长岩锆石U-Pb年龄38～40 Ma相吻合,表明Shangalon Cu-Au-Mo成矿作用与始新世闪长岩-花岗闪长岩侵入体密切相关,为始新世岩浆活动的产物.Shangalon铜金矿床辉钼矿样品的Re含量为 82.4～111.2 µg·g-1,平均值为 98.88 µg·g-1,指示成矿物质具有壳幔混源的特征.通过综合分析区域成矿动力学背景,认为Shangalon地区始新世铜金成矿作用可能形成于印度与欧亚大陆碰撞背景下的新特提斯洋板片撕裂和断裂,诱发软流圈上涌,新生下地壳部分熔融.
Abstract
The Shangalon copper-gold deposit is located in the northern segment of the Wunto-Popa magmatic arc in Myanmar.The research on this deposit is limited,and there is a lack of high-precision isotopic geochronological data regarding its ore-forming geological background and deposit genesis.In this study,five molybdenite samples from typical ores were selected to determine the mineralization age using the Re-Os isochron dating method.The obtained model ages range from 38.3±0.6 to 38.5±0.5 million years ago(Ma),with a weighted average age of 38.4±0.2 Ma.The corresponding isochron age is 38.0±1.6 Ma(MSWD=0.17).Both ages are in good agreement within the error range,indicating that the mineralization timing of the Shangalon copper-gold deposit is in the Eocene epoch.This age data corresponds well with the zircon U-Pb ages of 38 to 40 million years for the mineralized syenogranite and granodiorite in the mining area,suggesting a close relationship between the Shangalon Cu-Au-Mo mineralization and Eocene syenogranite-granodiorite intrusions,which are products of Eocene magmatic activity.The Re contents of molybdenite samples from the Shangalon copper-gold deposit range from 82.4 to 111.2 µg·g-1,with an average value of 98.88 µg·g-1,indicating a mixed source from the crust and mantle for the mineralizing fluids.Based on a comprehensive analysis of the regional metallogenic dynamics,it is suggested that the Eocene copper-gold mineralization in the Shangalon region possibly formed as a result of the fragmentation and faulting of the Neo-Tethys oceanic plate,triggered by the collision between the Indian and Eurasian continents,leading to upwelling of the asthenosphere and partial melting of the lower crust.
关键词
辉钼矿/Re-Os同位素定年/Shangalon铜金矿床/Wunto-Popa岩浆弧/缅甸Key words
molybdnite/Re-Os isotopic ages/Shangalon Cu-Au deposit/Wunto-Popa magmatic arc/Myanmar引用本文复制引用
基金项目
国家自然科学基金重点项目(92055314)
&&(DD20230127)
四川省"天府万人计划"杰出科学家项目(川万人第 023号)
云南省科学技术奖-杰出贡献奖项目(2017001)
出版年
2024
国家科技期刊平台
NSTL
万方数据