Radiometric dating zircon crystals
That radius is typical of the zircons studied by the RATE group and others and the diffusion rate is extrapolated from their data.The figure shows that the helium concentration needs nearly 50,000 years to drop to approximately 0.1 times the original level, while nearly 100,000 years are needed for the residual level to reach 0.02 times the original.The question remains, can this theory accurately predict the radiogenic helium levels in zircon specimens from sites other than the Fenton Hill well?To answer this question, I will make some predictions based on RATE’s data and conclusions and then compare them with field observations.This team, supported by several creationist organizations, exists to disprove the validity of radiometric dating.RATE’s latest undertaking concerns some microscopic zircon crystals recovered from a well near Fenton Hill, NM.Thus, the crystals cannot really be 1.5 billion years old rather they are only a few thousand years old. The RATE research includes some limited analyses of helium contents of some zircon crystals, some diffusion rate measurements and calculations to support their claims about the short time of the diffusion process. The authors of the RATE zircon-helium study claim that their primary thesis, that the earth is only 6000 years old, is vindicated by their calculations of the expected residual helium levels in the Fenton Hill zircon crystals.They claim that their "theory" has predictive power because they can use it to correctly calculate the remaining helium levels in zircons from various depths (and temperatures) in the well.
The uranium/lead age gives the time of initial formation, while the helium age tells when the crystal cooled to a temperature at which the helium was essentially all retained.
The ratios of uranium and thorium to the corresponding daughter product lead isotopes can be used to date the time of formation of the crystal, based on the known half-lives of the original uranium and thorium isotopes.
In theory, the helium contents can also be used for dating the crystals, but generally are not because at elevated temperatures the helium will rapidly diffuse out. Kenneth Farley of the California Institute of Technology and Dr.
The argument, presented in a creationist journal goes like this: The rock formation is radiometrically dated at about 1.5 billion years of age.
The zircons contain uranium and thorium which have decayed to their daughter products including helium.