摘要
A UV laser ablation microprobe-inductively coupled plasma mass spectrometry （LAMICPMS） is used to determine the Pb/Pb and Pb/U ages of several zircon grains whose ages have been measured by the conventional U-Pb thermal ionization mass spectrometry （TIMS） method. The mass fractionation factor of Pb isotope ratio was typically between 0.010--0.012 and corrected by NIST610 glass standard. Several factors that influence the stability of Pb/U ratio have been investigated and optimized. The precision of <sup>207</sup>pb/<sup>206</sup>Pb and （206）pb/<sup>238</sup>U from each sampling crater is within 0.6%—2.4% and 1%—10% respectively, while the precision for the average of mean ratios from different craters is 0.7% and 6% correspondingly. The <sup>2</sup>07)Pb/<sup>206</sup>pb and <sup>206</sup>pb/<sup>238</sup>U age differences compared with TIMS results are 《1% and 【3% respectively.
A UV laser ablation microprobe-inductively coupled plasma mass spectrometry (LAMICPMS) is used to determine the Pb/Pb and Pb/U ages of several zircon grains whose ages have been measured by the conventional U-Pb thermal ionization mass spectrometry (TIMS) method. The mass fractionation factor of Pb isotope ratio was typically between 0.010-0.012 and corrected by NIST610 glass standard. Several factors that influence the stability of Pb/U ratio have been investigated and optimized. The precision of207Pb/206Pb and206Pb/238U from each sampling crater is within 0.6%—2.4% and 1%—10% respectively, while the precision for the average of mean ratios from different craters is 0.7% and 6% correspondingly. The207Pb/206Pb and206Pb/238U age differences compared with TIMS results are ? 1% and < 3% respectively.
