INTRODUCTION TO RADIOMETRIC DATING

Extract from Book of Mormon Stories Unearthed

In this article we propose two new dating sequences—one for geology, and one for archaeology. It is important to remember that these are two separate sequences. The calibrated timeline for geology is much different than the calibrated timeline for archaeology because scientists in these two fields use very different methods to date objects. Archaeologists primarily use carbon dating and dendrochronology (tree-ring dating) for “absolute” dating, and a myriad of relative dating methods to fill in the gaps. Geologists typically use various radiometric dating methods for “absolute” dating (such as uranium-lead dating and potassium-argon dating) and they use superposition and common sense observations for relative dating.

In order for carbon dating to give valid results, it must be assumed that the ratio of stable carbon (carbon-12) to radioactive carbon (carbon-14) has been constant throughout earth’s history. However, there are many factors which affect this ratio and geological research has shown it to vary greatly over time [1] . Carbon-14 is formed from nitrogen-14 by cosmic rays in the upper atmosphere; therefore, any change in the number of cosmic rays that reach the upper atmosphere alters the carbon ratio [2] . Factors which affect cosmic rays reaching the upper atmosphere include: the amount of solar energy produced by the sun, the intensity of Earth’s magnetic field, and the density of the earth’s cloud cover [3] . The ratio is also affected by the frequency and magnitude of volcanic eruptions which eject large quantities of Carbon-12 into the atmosphere and create dust clouds that block solar radiation [4] . The ratio of carbon-12 to carbon-14 is also affected by the erosion of ancient carbonate rocks; the erosion of these rocks releases carbon-12 into the world’s oceans where it is then released into the atmosphere [5] .

In our research we have found that carbon dates grow increasingly old before the time of Christ (see tables throughout paper). Following the time of Christ the trend seems to reverse. If our proposed dates are correct, then before the time of Christ there must have been less carbon-14 or more carbon-12 in the atmosphere then there is currently. For the trend to reverse following the time of Christ would require a large amount of carbon-12 to be introduced into the atmosphere between A.D. 50 and A.D. 400 and the ratio to then restabilize between A.D. 400 and the present. Supporting research is beginning to appear.

First of all, scientists have found evidence that the sun was dimmer in ancient times than it is today [6] , which means less carbon-14 would have been formed anciently. Scientists also believe that the intensity of earth’s magnetic field was stronger in ancient times [7] , so again, less carbon-14 would have been formed as a stronger magnetic field diverted more cosmic rays from the earth [8] .

Additionally, it is possible that there was less nitrogen in the ancient atmosphere because of microscopic organisms called cyanobacteria. These organisms “fix” nitrogen, taking it out of the atmosphere by metabolizing it. They are one of the few organisms able to do so. [9] Research shows that cyanobacteria were much more numerous anciently than they are today [10] .

These two factors point to a carbon-14 poor ancient atmosphere. Thus ancient organisms would contain a higher-than-normal ratio of carbon-12 to carbon-14 in their bodies just due to their environment and not due to their great antiquity.

The reversal of dates around A.D. 50 is likely connected to the great destruction that occurred at the death of Christ. As discussed previously, these destructions involved extensive volcanism [11] . It also caused the catastrophic draining of many ancient inland seas and a subsequent ice age which eroded immense amounts of ancient carbonate sandstones and limestones in the West [12] . Together, these events introduced huge amounts of carbon-12 into the atmosphere reversing the trend for a short period [13] .

Despite the problems inherent in carbon dating, however, it is still a very good relative dating tool, and as such is extremely valuable.

Geologists use radioactive elements in order to find “absolute” dates of rocks. This process of radiometric dating is only accurate if no air contaminates the rock from the time it solidifies until the time the scientist measures the different elements in the rock. However, sometimes air does contaminate rocks—for example, two scientists from the Hawaii Institute of Geophysics found that lava rock known to be less than 200 years old was dated as being between 10 million and 29 million years old. The scientists said they believed argon from the air had entered the rock and contaminated it. [14]


See Book of Mormon Stories Unearthed for a complete Bibliography

[1] Earth pg. 400-401

[2] McGraw-Hill pg. 140-141; Prehistory pg. 13-16; People pg. 17

[3] McGraw-Hill pg. 140-142; Prehistory pg. 13-16; People pg. 17

[4] McGraw-Hill pg. 142

[5] McGraw-Hill pg. 142

[6] Biology pg. 27

[7] Grolier: Earth, geomagnetic field of

[8] McGraw-Hill pg. 141

[9] Biology of Plants, pg. 197

[10] Zoology, pg. 48

[11] Underfoot pg. 4-6; Grolier, Earth, Geological History of; Grolier, Cretaceous Period; Utah pg. 1-10, 53-60, 94-103; Geology pg. 329-332

[12] Utah pg. 7-10, 66-89

[13] McGraw-Hill pg. 142

[14] Noble pg. 265-266