摘要
公认的Re-Os同位素定年代表物辉钼矿,目前已在金属硫化物矿床年代学研究领域获得了广泛的应用。本研究采用浓HNO_3分解辉钼矿样品,大大地简化了Re和Os的化学制备过程,并根据辉钼矿中正常Os含量水平相对放射成因^(187)Os可以忽略的特点,以正常Os标准为稀释剂,实现了仪器测量过程中Os同位素质量分馏的在线校正,改善了分析数据的质量。该方法经辉钼矿国家标准物质进行验证,获得了满意的Re、Os含量及Re-Os年龄数据,并且在南岭地区与连阳复式岩体相关的姓坪夕卡岩型钼矿床成矿年龄研究中获得了成功应用。在实际应用中,为了获得有意义的能反映真实地质事件的年龄数据,辉钼矿样品不仅要有足够的取样量,而且还要保证粒度细、混合均匀。
As a robust proxy,molybdenite has been widely applied to determination of Re-Os age.This study simplified the chemical separation of Re and Os using concentrated HNO_3 for digestion of molybdenite.Based on the negligible level of common 0s relative to radiogenetic ^(187)Os in molybdenite,a common Os standard was used as spike,and as a result,Os isotopic mass fractionation during ICP-MS measurements could be on-line corrected,improving the quality of analytical data This method was validated using national certified molybdenite standards,and the results were well consistent with the certified values.Using this method for determination of molybdenite sampled from Xingping skarn-type Mo deposit,Liangyang granite composite,reasonable Re-Os age data have been obtained.In practice,it is suggested to use enough amounts of molybdenite,which should be homogenized fine-grain in order to obtain representative Re-Os age.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2010年第2期642-648,共7页
Acta Petrologica Sinica
基金
国家重点基础研究发展规划项目(2007CB411303)
中国科学院"百人计划"和"创新团队国际合作伙伴计划(KZCX2-YW-T004)"联合资助
关键词
RE-OS同位素体系
辉钼矿
姓坪钼矿
连阳岩体
Re-Os isotope system
Molybdenite
Xingping molybdenum deposits
Lianyang granite composite