摘要
利用激光探针等离子体质谱（LAM－ICPMS）技术对中生代钻石进行了详细的206Pb／23U定年研究。采用线扫描（Linescan）进样法减小了传统的剥深（Depthprofile）进样法所引起的激光熔蚀分异效应；优化仪器参数可消减ICP－MS对Pb和U的质量歧视效应；测得了精确的206Pb／238U比值及年龄。研究结果表明，均匀颗粒锆石的206Ph／238U比值测量精度为2％～10％，定年精度和准确度优于3％；对大颗粒（100～160μm）及均匀的年轻锆石U－Pb定年可与灵敏的高分辨离子探针（SHRIMP）定年结果相比。
A new method of U-Pb isotopic dating for young zircons using Laser Ablation Microprobe-Inductively Coupled Mass Spectrometry (LAM-ICPMS) has been developed. The fractionation of U/Pb during laser ablation sampling was minimized by using a linear scanning method compared to the conventional depth profile method. By optimizing the fore-quadrupole offset voltage, the mass discrimination effect on 206Pb and 238U from ICP-MS was decreased. Precise 206Pb/238U isotopic ratios and ages of four young zircons were successfully measured. For homogeneous single young zircon grains, the 206Pb/238U ratios with precision of 2% ~ 10% (RSD) can be obtained,whilst both precision and accuracy are better than 3%. It can be concluded that, for homogeneous and large (100 ~ 160 μm) young zircons, the U-Pb dating results measured by LAM-ICPMS method can be comparable with that by SHRIMP technique.
出处
《地球化学》
CAS
CSCD
北大核心
2000年第1期1-5,共5页
Geochimica
基金
国家杰出青年基金!49725309
中国科学院广州分院1998~1999年测试基金
关键词
激光探针
等离子体质谱
锆石
铀-铅定年
laser ablation microprobe
inductively coupled plasma-mass spectrometry
young zircons
^(206)Pb/^(238)U
dating
