IMPACT No. 301

Dr. Andrew Snelling of AIG continued the geological emphasis with a paper entitled, "Solving the Long-Age Isotope Dating Problem: Geology and Geochemistry." He reported on the K-Ar analyses of recent (less than 50 years old) lava flows at Mt. Ngauruhoe, New Zealand, which produced model ages as high as 3.5 million years. The large age is due to excessive concentrations of primordial argon in the samples which renders problematic the use of K-Ar and Ar-Ar as methods for dating rocks. It is not possible to distinguish the primordial argon incorporated as a rock formed from that produced later by nuclear decay. Dr. Snelling demonstrated that argon is infiltrating the crust of the earth from reservoirs in the mantle over various space and time scales. Additionally, the Sm-Nd, Rb-Sr, and U-Th-Pb dating methods also rely on assumptions about the initial starting conditions in the earth's mantle. Various hypothetical models for different compositional domains in the mantle are utilized by geochemists to explain the measured isotope ratios in crustal rocks, in some instances without resorting to age interpretations. Dr. Snelling intends to pursue this explanation as an alternative to accelerated decay.
 

Dr. Donald DeYoung, an associate editor with the Creation Research Society Quarterly and professor at Grace College in Indiana, in response to a request to begin writing chapters for the Status Report to be published by the RATE group in the year 2000, presented a paper entitled, "Radiometric Dating Review." In this paper he discussed the procedures and assumptions of seven of the more popular dating methods used for rocks, including samarium-neodymium, rhenium-osmium, uranium-lead, thorium-lead, rubidium-strontium, potassium-argon, and argon-argon. He stressed that all of these methods make three main assumptions. In all cases it is assumed in conventional age dating that the nuclear decay rate or half-life has always remained constant,that the isotopic composition of rock samples has not been changed by fractionation over time, and that rock samples have been closed systems over time with no migration of parent or daughter elements into or out of the rocks. Dr. DeYoung then explored briefly the magnitude of accelerated decay necessary to explain all of the daughter products typically found in rocks.

Dr. D. Russell Humphreys, a physicist at Sandia National Laboratory in Albuquerque, New Mexico, presented a paper entitled, "Helium Diffusion through Granite." Dr. Humphreys offered both experimental and theoretical data to support his hypothesis that the concentration of helium is too high in certain minerals in granite if the earth is billions of years old. The diffusion rate of helium through granite should have permitted most of the helium to have already "leaked" into the atmosphere. However, if an accelerated decay event occurred only a few thousand years ago, the measured concentrations of helium would be consistent with the calculated diffusion rate. Helium is produced by radioactive decay of uranium and thorium within zircon crystals embedded in biotite flakes of granite. Although the diffusion rate of a similar gas, argon, has been measured in biotite, no results for helium diffusion have been reported in the literature. The predictions of diffusion rates between the two age models differ by five orders of magnitude. Dr. Humphreys suggested that a high-priority experiment for the RATE project should be a well-designed and executed laboratory experiment on the diffusion rate of helium through biotite.

Dr. Keith Wanser, a professor of physics at California State University Fullerton, was invited to present a paper to the RATE group entitled, "Non-Exponential Decay of Quantum Mechanical Systems Due to Tunneling." Although Dr. Wanser is not part of the steering committee for the RATE project, he was invited to participate on the first day of presentations because of the possible significance of his research to the effort. The RATE group plans to include other researchers in the formal presentations from time to time, on an invited basis, as appropriate research and opportunities occur. Dr. Wanser's presentation dealt with the rigorous quantum theory of time-dependent tunneling, which produces non-exponential time dependence in nuclear decay rates. The difficulty in making these calculations is finding analytical methods which will allow computation of the decay probability over an extreme range of time scales (at least 37 orders of magnitude). He has found an analytical solution for the Green's function which reduces the time dependence of the decay probability to the evaluation of a single integral. For the alpha decay problem, he plans to investigate neodymium first, which has the longest half-life (2.1 x 10¹⁵ years) and the lowest alpha particle energy (1.83 MeV) of any alpha emitter. As such, it is expected to exhibit the greatest non-exponential decay effects at short times.

The Status Report and Research Plan will be published jointly by ICR, AIG, and CRS in the summer of 2000. Following release of this report the RATE group plans to conduct research on this project for a period of five years and report on the progress in the year 2005.

* Dr. Vardiman is Executive Vice President of ICR and Chairs the Astrogeophysics Department of the ICR Graduate School.