Re-Os dating of Mo-bearing black shale of the Laoyaling deposit, Tongling, Anhui Province, China  

作　　者：YANGGang CHENJiangfeng DUAndao QUWenjun YUGang 

机构地区：[1]SchoolofEarthandSpaceSciences,UniversityofScienceandTech-nologyofChina,Hefei230026,China//NationalResearchCenterofGeoanalysis,Beijing100037.China [2]SchoolofEarthandSpaceSciences,UniversityofScienceandTech-nologyofChina,Hefei230026,China [3]NationalResearchCenterofGeoanalysis,Beijing100037.China

出　　处：《Chinese Science Bulletin》2004年第13期1396-1400,共5页

摘　　要：Laoyaling is a typical stratiform deposit in the Tongling district and the molybdenum orebody is hosted by black shale of the Dalong Formation of the Upper Permian system. Eight black shale samples from the Laoyaling Mo orebody were dated by Re-Os technique using ICP-MS,which give an isochron age of 234.2±7.3 Ma with an initial ^187Os/^188 Os ratio of 1.37±0.39. The apparent Re-Os age is a few million years younger than the depositional age of the Late Permian. The young isochron age may be caused by the later hydrothermal disturbance or mass fractionation during ICP-MS measurement. However, the obtained isochron age is close to the depositional age and far earlier than those of the Late Yanshanian intrusions. It suggests that the Mo ore of the Laoyaling deposit is sedimentary in origin and not related to the Late Yanshanian magmatism. Black shales of the Upper Permian are distributed widely in the Mid-Lower Yangtze region, our result is important for understanding the ore-forming processes in the region and broadens the exploration target.Laoyaling is a typical stratiform deposit in the Tongling district and the molybdenum orebody is hosted by black shale of the Dalong Formation of the Upper Permian system. Eight black shale samples from the Laoyaling Mo orebody were dated by Re-Os technique using ICP-MS, which give an isochron age of 234.2±7.3 Ma with an initial 187Os/188Os ratio of 1.37±0.39. The apparent Re-Os age is a few million years younger than the depositional age of the Late Permian. The young isochron age may be caused by the later hydrothermal disturbance or mass fractionation during ICP-MS measurement. However, the obtained isochron age is close to the depositional age and far earlier than those of the Late Yanshanian intrusions. It suggests that the Mo ore of the Laoyaling deposit is sedimentary in origin and not related to the Late Yanshanian magmatism. Black shales of the Upper Permian are distributed widely in the Mid-Lower Yangtze region, our result is important for understanding the ore-forming processes in the region and broadens the exploration target.

关 键 词：Re-Os年代测定 钼矿柱页岩 沉积物 安徽 MO 矿石 

分 类 号：P618.65[天文地球—矿床学] P597.3[天文地球—地质学]