Isochrons And evolutionary Dati
ISOCHRONS AND EVOLUTIONARY DATING
by Dr. Steven Austin
As the media constantly tells us, the Grand Canyon is supposed to be “Exhibit A” proving evolution. But have those Grand Canyon rocks really been proved to be billions of years old? Is the media giving us the correct story? I wrote the paper “Grand Canyon Lava Flows: A Survey of Isotopic Dating Methods” (Institute for Creation Research Impact No. 178, April 1988) to summarize some of my recent work on potassium-argon (K-Ar) and rubidiumstrontium (Rb-Sr) dating of Grand Canyon rocks.
The Rb-Sr isochron date of 1.1 billion years for the deeply buried Cardenas Lavas (Precambrian) has been considered by evolutionary geologists to be the “most secure” isotopic date yet made for Grand Canyon strata.
Several geologists have asked me if such a well documented date can be questioned. They observe that the isochron method appears to internally validate the assumptions of the dating method which creationists have criticised. They even note that the Rb-Sr isochron of 1.1 billion years for the Cardenas Lavas overturned five K-Ar dates which gave a younger age (K-Ar Lavas before the Rb-Sr isochron was generated).
I decided two years ago to generate my own “isochron dates” from published isotopic ratios and elemental analyses. My computers are able to do the data manipulation to plot isochrons. I have started the project by working on Grand Canyon lava flows. The Western Grand Canyon lava flows (Pleistocene) flowed over the rim of the Grand Canyon and blocked the Colorado River. These lava flows lie on the surface and look as fresh as recent Hawaiian flows.
These Western Grand Canyon flows yielded a good “isochron date” of 1.5 billion years, making them among the “oldest” strata yet dated in the Grand Canyon. This isochron is shown in my recent article (ICR Impact No. 178, April 1988).
Other geologists and I have referred to these erroneous dates as “fictitious isochrons.” These, I believe, cast severe doubts on some of the “accepted” isochron dates. Fictitious isochrons need to be recognized and discussed.
The subject of radiometric dating can become very theoretical and may get to be a “can of worms” in a hurry. However, I do invite your comments on my short article and want to discuss various methods of dating Grand Canyon rocks. I recommend that we start by keeping the discussion on real rocks from the Grand Canyon and limit our discussion to the popular methods used by the media and geologists to date Grand Canyon rocks. But please–no philosophy, religious arguments, theoretical models, cosmological speculation or polemics! I’m only interested in the facts.