Decades ago, some opponents of evolution argued that God had placed the fossils in the ground to test us. Contrary to contemporary misrepresentations used to slander creationists as unsophisticated, modern creation scientists (yes, scientists!) accept that fossils are the remains of actual living creatures, arguing that most of them were buried in Noah’s flood recorded in Genesis. This book focuses not on the biological evolution debate centered around fossils of animals, but rather on the geological evolution debate and looks at a different set of fossils: evidence of past radioactive decay such as decay daughter isotopes, radiohalos and fission tracks. In the late 1990s and early 2000s, a group of creation scientists did an extensive study called RATE, Radioisotopes and the Age of the Earth, publishing a variety of scientific papers and two large technical reports. This book is a high-level summary written to be understood by non-scientists that also answers some objections to the RATE conclusions.
According to traditional radioisotope dating, the earth is 4.5 billion years old; in contrast, the traditional interpretation of Genesis yields about 6,000 years of age. This presents a bit of a dilemma with a number of possible resolutions:
1. God created the present radioisotope inventories, radiohalos, fission tracks, etc. to produce an appearance of age.
2. The existing radioisotope inventories reflect 4.5 billion years of radioactive decay at current decay rates, but there were periods of time in the past when decay rates were higher, accounting for the present inventory.
3. The Genesis creation account was not meant to be taken literally, rather to communicate truths about God being responsible for creation without reflecting exactly what He did.
The RATE study considered the first option but rejected it due to the strong evidence of radioactive decay. It also engaged a Hebrew scholar to critically evaluate the third option. Because the writing style and verb usage so decisively correlated with narrative history in the Old Testament rather than with poetry in the Old Testament, the RATE team likewise rejected it, as well, leaving option 2. With the exception of a chapter summarizing the Hebrew linguistic study, the bulk of the book is focused on how the RATE study dealt with option 2.
Early on, the book explains the radioactive dating process and its underlying assumptions:
1. The initial conditions (as in, when the rock was formed) of the sample are known accurately.
2. We can tell whether the rock being sampled has exchanged atoms with the surroundings during its history.
3. The half-lives of the isotopes under consideration have remained constant since the rock was formed.
A method known as isochrons is used to validate the first two assumptions for any given radioactive dating method. The method seems a bit like voodoo to me, but it appears to focus on ratios of different radioisotope concentrations, the ratios expected when the rock was formed and the current ratios based on decay rates. If they are off relative to each other, the initial conditions might not have been as expected, or radiosotopes may have been transported into or out of the rock during its history, compromising the ability to properly date the rock.
After this explanation of radioactive decay for the benefit of the average reader, the book turns to evidence of a young earth. One method of dating organic materials is carbon-14. When a plant or animal is alive, its carbon-14 inventory is in equilibrium with the environment as a result of biological processes such as eating and breathing. Once it dies, the processes causing this equilibrium stop, and the carbon-14 inventory starts a slow reduction due to radioactive decay. Assuming that the equilibrium carbon-14 concentration in the environment has remained constant (based on a baseline date of 1950, prior to large-scale nuclear weapons testing, which has affected the carbon-14 inventory in the environment), the ratio of the carbon-14 in the sample to that in the environment can be used to identify how long ago the plant or animal died. Because carbon-14 would decay away to negligible levels within 100,000 years, this dating method is valid only for samples below that age. The RATE team did radiocarbon dating of coal dated between 34 and 311 million years of age by traditional dating, diamonds (assumed to be millions or even billions of years old) and found detectable levels of carbon-14, all within an order of magnitude of each other, suggesting a much younger age than millions of years. The book provides an analysis of the results and answers alternative explanations by proponents of the traditional chronology.
Zircons, crystalline ZrSiO4, are often found in granite along with the main mineral component: quartz, feldspar and biotite. Because uranium and thorium are chemically similar to zirconium, they sometimes replace zirconium at various points in the crystal matrix and then decay to lead via decay chains that include several alpha decays, as well as beta decays. When a nucleus undergoes alpha decay, it emits an alpha particle, a helium nucleus. In larger zircons, the alpha particle doesn’t have sufficient energy to propel itself out of the zircon. Afterwards, it can diffuse out of the zircon and surrounding rock. The RATE team sampled some zircons from borehole rock dated to 1.5 billion years based on lead-lead dating. More than half of the helium from radioactive decay in the zircons was still in the zircons and most of the remainder that had diffused out was still in the surrounding biotite. This discovery prompted the RATE temp to research helium diffusivity in zircon crystals and in biotite. Based on diffusivity results and the helium concentrations still in the zircons and surrounding minerals, statistical analysis yielded an estimated age for the zircons of 6,000 ± 2,000 years, a much shorter time than the 1.5 billion year lead-lead age. If the rocks were 1.5 billion years old, the helium should not still be there. As with the carbon-14 discussion, the book answers alternative explanations for the helium retention.
The chapter describing radiohalo research is quite interesting. As discussed above, uranium and thorium atoms in the crystal structure of zircons decay via a decay chain of alpha and beta decay events. The energy level of the alpha particle depends on the radioisotope in the decay chain that is decaying. As mentioned above, the alpha particle cannot propel itself out of a large zircon, but it can propel itself out of smaller zircons into the surrounding biotite. Since even a small zircon will have many decay events over its lifespan, alpha particles will be emitted in all directions. As they pass through the crystal structure of both the zircon and the biotite, the alpha particles lose energy by colliding with atoms, knocking them out of position. If there are sufficient such events, the result is a discoloration known as a radiohalo, the radius of which is a function of the energy level of the alpha particles. Alpha particles emitted with higher energy travel farther, producing larger radiohalos. If the radionuclides in a small zircon remain in place, the result is a radiohalo consisting of concentric rings for the different energy levels of the different alpha decays in the decay chain. Radiohalos in rocks from different geologic eras were studied. The flood geology paradigm of the creation scientists considers Precambrian rock to be pre-flood and most of the subsequent rock layers to have been deposited during the flood. The rocks with the highest concentrations of radiohalos were not pre-flood rocks, as might be expected based on age, but the younger rocks of the flood layers. This is potential evidence for shortened half-lives during the flood. One mystery identified in these studies is the existence of orphan radiohalos, in which the concentric rings associated with alpha decays early in the decay chain are missing. The book discusses various possible explanations, including liquid transport of radioisotopes from one location to another between decay events and the timing of magma cooling.
Aside from the decay chains discussed above, uranium atoms in zircons can also decay by spontaneous fission. When this happens, the fission products, two nuclei, each having around half the mass of the original uranium nucleus, are propelled outward with a substantial amount of kinetic energy, leaving a trail of damage to the crystal structure. Because spontaneous fission has its own half-life, the concentration of the fission tracks in a sample is an indication of the age of the rock. It appears that the RATE team used fission track dating to validate the amount of radioactive decay determined by helium retention/diffusion and radiohalos discussed above. There were few inconsistencies between fission track studies and the above-mentioned studies. If crystalline rocks containing such radiation damage as fission tracks and radiohalos are heated above a certain temperature, they will anneal, a process in which the crystalline structure repairs itself and erases the radiation damage, a process that makes the rock look “younger” from the standpoint of radiation damage.
There are several different radioactive dating methods suitable for geologic strata that use different decay chains. The RATE team did a test of consistency between different methods by having rock samples from different parts of the world dated by different methods and comparing the results. The methods tested in this manner included potassium-argon, rubidium-strontium, lead-lead and samarium neodymium. Sometimes the different methods yielded results consistent among themselves and with the published ages of the rock strata under consideration. However, there were several instances where the different methods yielded wildly different ages inconsistent with each other and with published dates. The most interesting instance of this was andesite samples from Mount Ngauruhoe in New Zealand, which most recently erupted in the 20th century (1949, 1954 and 1975). In other words, the samples were from lava flows less than 100 years old. Ages measured by Rb-SR, Sm-Nd and Pb-Pb methods ranged from 3.5 million years to 3.908 billion years years for rocks only a few decades old. This was by no means the only age discrepancy but was the most dramatic. The book discusses a number of theories as to the nature and origin of these discrepancies, including inheritance of radioisotopic inventory from source material (initial conditions), mixing between the magma and surrounding crustal rocks (exchange with surroundings) and non-constant half-lives over geologic history. In short, these results challenge all three underlying assumptions of the radioactive dating process.
Finally, the book explores the concept of accelerated radioactive decay. This section discusses the mechanism of alpha decay via quantum mechanical tunneling and acknowledges that the how and why of accelerated radioactive decay is the subject of ongoing research. The lack of a mechanism for accelerated decay is not the only weakness. Accelerated decay would produce lethal levels of radiation, impacting when it could occur without affecting life. The RATE team posits that it would be limited to the first two days the creation week, before the creation of life, and the flood year. Furthermore, there is the problem of the immense levels of heat generation from the accelerated decay. How does the heat dissipate out of the rocks fast enough to keep the rock temperature below the annealing temperature at which radiation damage to the crystalline structure is erased? This is the question that troubles me the most. The RATE team has proposed cosmological cooling via cosmological inflation as a possible mechanism. This is a tantalizing idea in that Noah and his family would have walked off the ark to see an apparent new earth as well as new heavens. Even so, it is not clear to me how this cooling mechanism would get the heat out of the rocks fast enough to keep their temperature low enough. I hope to see more research in this area.
While there remain holes in the creationist paradigm, the work of the RATE team has also poked some holes in the ruling old earth paradigm. Personally, I would prefer to see more research in certain areas of the paradigm, I am very much aware that the creationist paradigm is a minority view. Resource limitations necessarily impede progress. In addition, there have been other obstacles. For example, Andrew Snelling, one of the RATE researchers whose work is summarized in part of this book, had difficulty getting permission to perform rock samples in the Grand Canyon for subsequent research (Rock samples from the Grand Canyon had been used in some of the RATE research.), and had to resort to a lawsuit to get permission to get the samples. I don’t what his research plan was, but this delayed it by four years, from 2013 to 2017.
For the record, I am a nuclear engineer by profession but have a lot more experience with heat transfer and fluid flow analysis than with radiation analysis. My geology background is limited to secondary education. If anything, this book has inspired me to read up further on geology and radioactive dating to better evaluate its claims. Yes, I am a creationist, but have been reading works by both creationist and non-creationist scientists and will continue to do so.