金川铜镍矿床年龄和源区同位素地球化学特征  

Age of the Jinchuan Copper-Nickel Deposit and Isotopic Geochemical Feature of Its Source

作　　者：张宗清[1] 杜安道[2] 唐索寒[1] 卢纪仁[3] 王进辉[1] 杨刚[2] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]国家地质实验中心,北京100037 [3]中国地质科学院矿产资源研究所,北京100037

出　　处：《地质学报》2004年第3期359-365,共7页Acta Geologica Sinica

摘　　要：本文报道了金川铜镍硫化物矿床 Sm- Nd、Rb- Sr、Re- Os同位素年龄测定结果 ,讨论了矿床物质源区。金川铜镍矿床 Re- Os年龄为 10 4 3± 2 8(2 σ) Ma,IOs=0 .15 0 3± 5 0 (2 σ) ;Sm- Nd等时年龄约 0 .97± 0 .31(2 σ)Ga,INd=0 .5 110 6± 2 8(2 σ) ;Rb- Sr等时年龄约 819Ma,ISr=0 .7118。矿床物质来自富集地幔源区。The Jinchun copper-nickel sulfide ore deposit is located in the Jinchang city, Gansu Province, China. It contains multiuseful components and is largest nickel deposit in China. Its forming age has not been still established although more dating works were done. Generally considered that the ore deposit was formed in the middle Proterozoic about 1508Ma and its materials was from upper mantle source, i.e. deplete mantle source. However, the ideas are not proved by our new obtained Sm-Nd, Rb-Sr, Re-Os isotopic geochronological and geochemical data. This paper reports the data and discusses the age and origin of this ore deposit. The Re-Os isotopic analytical data of dunite sulfide ore samples from the Jinchuan ore deposit define an excellent isochron of t=1043±28(2σ)Ma, corresponding to ( 187Os/ 188Os) i=0.1503±50(2σ), MSWD=1 3. The Sm-Nd isotopic data of ultramafic rocks of the ore deposit , that are dispersed relatively, give a reference isochron age of t=0 97±0.31(2σ) Ga, ( 143Nd/ 144Nd) i=0.51106±28(2σ). The Rb-Sr isochron age approximates to 819 Ma with ( 87Sr/ 86Sr) i = 0.7118. Obviously, the ore deposit were formed in the late middle Proterozoic and ore-bearing intrusion were from the enriched-mantle source. The ore-forming geological function is relative to rifting and converging processes of Rodinia.

关 键 词：铜镍矿床 同位素 地质年代学 地球化学 

分 类 号：P618.4[天文地球—矿床学] P597[天文地球—地质学]