摘要
An attempt was made to use CO_2 laser step-heating method to date the late Pleistocene basaltic groundmass (DF-2) from Tengchong volcanic field. Among the fourteen heating steps, ten define a good inverse isochron (MSWD = 1.4) with an age of 32.2 ± 7.1 ka (2 σ).The inverse isochron also shows that the initial argon isotopic ratio is 297.1±2.0 (2σ) which is the same as the atmospheric argon at the 2σ error level. Study indicates that it is a useful means to date young volcanic groundmass with low K content by using CO_2 laser step-heating ^(40)Ar/^(39)Ar method.
An attempt was made to use CO2 laser step-heating method to date the late Pleistocene basaltic groundmass （DF-2） from Tengchong volcanic field. Among the fourteen heating steps, ten define a good inverse isochron （MSWD = 1.4） with an age of 32.2 ± 7.1 ka （2σ）.The inverse isochron also shows that the initial argon isotopic ratio is 297.1±2.0 （2σ） which is the same as the atmospheric argon at the 2σ error level. Study indicates that it is a useful means to date young volcanic groundmass with low K content by using CO2 laser step-heating ^40Ar/^39Ar method.
基金
This work was supported by National Natural Science Foundation of China(Grant No.40473031).
