There were no published measurements for helium diffusion through biotite, the mineral surrounding the zircons.
Until we had reliable numbers for these diffusion rates, we could not say for certain that the large retentions require a young earth.
These data strongly support our hypothesis of episodes of highly accelerated nuclear decay occurring within thousands of years ago.
Table I shows their results as samples 1 through 6.
Note carefully: Gentry’s large retentions are not what uniformitarians mean by “excess helium” (Baxter, 2003), a common mental pigeonhole into which they shove helium anomalies.
They crushed a core sample from a depth of 2,900 meters and extracted microscopic crystals of zirconium silicate (Zr Si O) embedded in the biotite.
These crystals, called zircons, were radioactive, containing high amounts of uranium and thorium relative to the rest of the rock, as is usual for that mineral.
Experiments co-sponsored by the Creation Research Society show that helium leakage deflates radioisotopic ages.
In 1982 Robert Gentry found amazingly high retentions of nuclear-decay-generated helium in microscopic zircons (Zr Si O crystals) recovered from a borehole in hot Precambrian granitic rock at Fenton Hill, NM.In 1998 a personnel transfer reduced the sponsoring organizations from three to two, ICR and CRS.Three board members of CRS have been on the RATE steering committee from the outset: Donald De Young, Eugene Chaffin, and Russell Humphreys.From the start, several members of the steering committee were convinced that episodes of greatly accelerated nuclear decay rates had occurred within thousands of years ago.For the preservation of life, such episodes seem possible only under special circumstances: (1) before God created living things, (2) after the Fall but well beneath the biosphere, and (3) during the year of the Genesis Flood, when the occupants of Noah’s ark would be safe from most radiation (Humphreys, 2000, pp. Accordingly, the steering committee planned a research program to test the accelerated decay hypothesis, and they wrote a book (jointly published by ICR and CRS) outlining the various projects (Vardiman et al., 2000).Combining rates and retentions gives a helium diffusion age of 6,000 ± 2,000 years.