磷灰石SIMS原位微区U-Pb-O同位素测试方法研究  

In Situ Analysis Method of U-Pb-O Isotope in Apatite by SIMS

作　　者：何升[1] 郭冬发[1] 崔建勇[1] 范增伟[1] 刘桂方[1] 武勇 HE Sheng;GUO Dongfa;CUI Jianyong;FAN Zengwei;LIU Guifang;WU Yong(Beijing Research Institute of Uranium Geology,Beijing 100029,China)

机构地区：[1]核工业北京地质研究院,北京100029

出　　处：《铀矿地质》2021年第6期1121-1130,共10页Uranium Geology

基　　金：中核集团启明星项目(编号:测QNYC2019-2);国家重点研发计划(编号:2017YFC0602600)资助。

摘　　要：磷灰石U-Pb-O同位素组成可为地质工作者提供年龄及流体来源等关键信息。相山铀矿田横涧铀矿床中大量产出同铀矿物共伴生的磷灰石,是成矿年龄及流体来源限定的良好对象。磷灰石SIMSU-Pb同位素测试参考样品PRAP、NW-1缺乏,用作LA-ICP-MS定年参考物质的MAD磷灰石具有较低的普通Pb组成。文章提出以MAD磷灰石作为参考样品开展SIMS定年工作,结果表明Durango、McClure磷灰石监控标样年龄分别为(34.4±1.9)Ma、(522±19)Ma,同年龄推荐值在误差范围内一致。利用Qinghu磷灰石作为O同位素分析参考标样,获得Durango磷灰石O同位素值(9.77±0.24)‰(2SD,n=15)、(9.67±0.18)‰(2SD,n=18),同推荐值在误差范围内一致。因此文章基于MAD、Qinghu磷灰石建立的二次离子质谱U-Pb-O同位素测试方法是可行的。Apatite U-Pb-O isotope compositions could provide the crucial information(e.g.ages,sources)for geology study.Apatite is also the important mineral associated with uranium minerals and could be used to study mineralization age and source.However,the lack of apatite reference materials for dating(PRAP,NW-1)restricts the above application due to the low the common Pb content of MAD apatite which is used to be a reference material for LA-ICP-MS dating.In this study,MAD apatite was proposed to act as a suitable reference material for SIMS dating.The tested results of proposed Durango showed that,McClure are(34.4±1.9)Ma and(522±19)Ma,which are consistent with the recommended values within error.The oxygen isotope results of Durango apatite are(9.77±0.24)‰(2SD,n=15),(9.67±0.18)‰(2SD,n=18)calibrated by Qinghu apatite,which are consistent with the recommended value.Based on these results,method presented in this article can be regarded as accurate.

关 键 词：U-Pb-O同位素 磷灰石 MAD磷灰石 SIMS 

分 类 号：O655[理学—分析化学]