摘要
用热离子发射质谱计、双带源分层蒸发锆石并将蒸发物附着到电离带上以测定^(207)Pb/^(205)Pb值年龄。对五个锆石样品的测定结果证明,用此方法获得的^(207)Pb/^(206)Pb值年龄与用常规锆石U-Pb一致线方法获得的年龄结果相吻合。这个方法不仅对放射成因铅轻微丢失的锆石适用,对严重丢失的也得到很好的结果。
The^(207)b/^(206)Pb ages for 5 zircon samples were measured by thermal evaporation of radiogenic lead directly from zircon grains of the mass spectrometer.This technique was established by Bernd Kober in 1987.The^(207)b/^(206)b apparent ages of these samples measured by the evaporation technique in this study are in good agreement with those obtained by the conventional method(see the following table).■as a spetial example,the U-Pb age of zircon sample CF85-67 suggests that the zircon in this sample has suffered serious radiodenic lead loss(at least 70%).But the apparent age obtained by the evaporation technique is consistent with that obtained by the U-Pb convertional method.This suggests that the single-grain zircon evaporation techniques can be used to determine the crystallysation age of those zircons which have lost most of the radiogenic lead.A multi-collecter MAT-261 mass spectrometer was used for this study and a SEM was used as the ion beam detector.The linearity of the SEM detector system was kept under control by analyses of the NBS 982 standard every day.
作者
刘敦一
赵敦敏
Liu Dunyi;Zhao Dunmin(Institute of Geology,Chinese Academy of Geological Sciences,Beijing)
出处
《地质论评》
1988年第6期496-505,共10页
Geological Review
