摘要
毛坪铅锌矿床是滇东北地区代表性矿床之一,目前尚缺乏精确的成矿年代学数据。该文对选自块状铅锌矿石的4件闪锌矿单矿物样品进行了Rb-Sr同位素定年,获得等时线年龄为321.7±5.8 Ma(MSWD=1.5),表明毛坪铅锌矿床的主成矿作用发生于石炭纪。此外,闪锌矿^(87)Sr/^(86)Sr初始值为0.712166±0.000017,低于大陆地壳^(87)Sr/^(86)Sr平均值(0.719)且高于地幔Sr初始值(0.707),暗示成矿物质主要来源于大陆地壳并混有少量地幔物质。综合前人研究成果,作者认为毛坪铅锌矿属后生矿床,与晚二叠世峨眉山大火成岩省玄武岩浆活动无成因联系,类似于典型的MVT矿床,且滇东北地区可能发育多期铅锌矿化作用。
The Maoping Pb-Zn deposit is a typical ore deposit in the northeastern Yunnan province. However, there is no precisegeochronological data to date. This research performed Rb-Sr isotopic dating on four sphalerite separated from the Maoping deposit,which yielded isochron age of 321.7 ± 5.8 Ma (MSWD=1.5), indicating that the mineralization age of the Maoping deposit wasCarboniferous. Moreover, the 87Sr/86Sr ratio of sphalerites is determined to be 0.712166 ± 0.000017. This result is lower than that ofcontinental crust (0.719) and higher than mantle (0.707), implying that the ore-forming metals were derived from continental crust witha minor amount of mantle-derived materials. Combining with the previous studies, we propose that the Maoping deposit is an epigeneticdeposit similar to the typical MVT Pb-Zn deposits and its mineralization has no link with Permian Emeishan flood basalts. Moreover,we also suggest that multi-stage Pb-Zn mineralization most likely occurred in the northeastern Yunnan province.
作者
沈战武
金灿海
代堰锫
张玙
张海
SHEN Zhanwu;JIN Canhai;DAI Yanpei;ZHANG Yu;ZHANG Hai(Chengdu Center,China Geological Survey,Chengdu 610081,China)
出处
《高校地质学报》
CAS
CSCD
北大核心
2016年第2期213-218,共6页
Geological Journal of China Universities
基金
中国地质调查局地质矿产调查评价项目(12120113053000
1212011085139
121201010000150002)资助
关键词
RB-SR同位素
成矿时代
物质来源
毛坪铅锌矿床
滇东北
Rb-Srisotopes
mineralization age
source of ore-forming materials
MaopingPb-Zn ore deposit
northeastern Yunnan province
