Dating volcanic rock
The age of a volcanic rock has been determined by ESR dating using the Ge center in quartz.The total dose of natural radiation and the age obtained from the Ge center are 460 krad and 2.07 ± 0.50 Ma, respectively, and those from the unidentified defect at = 2.011 are 484 krad and 2.16 ± 0.21 Ma, respectively.If a geologist claims to be 45 years old, that is an absolute age.
Considering that the dacite probably erupted in 1986 AD, Austin should have known that at least some of the samples would have given dates that were younger than 2 million years old and that Geochron Laboratories could not have provided reliable answers. 9), the K-Ar method cannot be used to date samples that are much younger than 6,000 years old (Dalrymple, 1991, p. 93)Cambridge, Massachusetts, USA, performed the K-Ar dating for Austin et al. However, when they did, their website clearly stated in a footnote that their equipment could not accurately date rocks that are younger than about 2 million years old ("We cannot analyze samples expected to be younger than 2 M. Development of the geologic time scale and dating of formations and rocks relies upon two fundamentally different ways of telling time: relative and absolute.
Relative dating places events or rocks in their chronologic sequence or order of occurrence.
When ‘parent’ uranium-238 decays, for example, it produces subatomic particles, energy and ‘daughter’ lead-206.