John Blanton and Jeff Umbarger
From the Newsletter of the North Texas Skeptics Volume 6 Number 4, April 1992
The flier from the Metroplex Institute of Origin Science (MIOS) advertised "The Scientific Evidence for the Age of the Earth." Since this is a subject of concern to anyone interested in modern science and cosmology, we decided to give it a look. Besides, neither of us had been to a meeting of MIOS since they moved their monthly lecture series to the Ridgewood Recreation Center in northeast Dallas, and we were anxious to see how they were doing in their new home. Just fine, it turns out.
We had concluded from the title that MIOS Chairman Don Patton would be presenting scientific evidence that our favorite planet was less than 10,000 years old. Our mistake. This is not to say that MIOS is one of those proponents of old Earth creationism. Far from it. Don's group is among those creationists who still maintain that the earth (and the universe of Carl Sagan, as well) was created just a day or two before the first humans appeared on the scene. In MIOS lectures previously Don has also been known to espouse periods of extremely rapid evolution, if you have not already guessed.
Hoping to see just how good the scientific evidence for the age of the earth is, we were told, instead, just how bad it is. Furthermore, the evidence presented was not from creationists but from honest-to-goodness, card-carrying scientists of the first kind. Really, folks. After taking in Don's complete lecture, we began to wonder why scientists even bother with the issue of the age of the earth. None of their methods ever seem to work for them. Radiometric dating methods, says Don Patton for example, are just about worthless, even according to anti-creationist scientists such as William D. Stansfield, author of Science of Evolution, which Don quoted often during his lecture.
Don's talk consisted to a large part of a discussion of citations from legitimate journals of science, these citations being mainly critical of modern geological dating methods. Following the lecture, MIOS was gracious enough to supply handouts of most of these citations, and that along with notes we made from the slide presentation enabled us to follow up on the evidence. One of us (Jeff) spent an evening at the UNT library making copies of the citations that could be located. The citations, as presented by Don, turned out to be even more interesting when compared with the complete text from the journals.
Here, from the MIOS lecture, is what appears to be a highly derogatory critique of radiometric dating practice. Under the heading "SHIFTY URANIUM" it reads:
"The fourth assumption presupposes that the concentration of uranium in any specimen has remained constant over the specimen's life. ...ground-water percolation can leach away a proportion of the uranium present in the rock crystals. The mobility of the uranium is such that as one part of a rock formation is being improvised another part can become abnormally enriched. Such changes can also take place at relatively low temperatures."
I note here that the text from the handout is reprinted exactly. The cited text was from an article in Scientific American by J.D. MacDougall entitled "Fission Track Dating" (see Note 1).
Although I had gotten the impression from Don's presentation (wrongly, it now seems) that this statement pertained to the uranium-lead dating method, a review of the complete text reveals that the process being discussed is, as the title indicates, dating of mineral samples by counting the tracks of nuclear fission products within crystals. Far from being critical of the method, the author promotes it highly in the complete copy. The "fourth assumption" being described by the author is the fourth, and the weakest of the required assumptions, the first three being 1) radioactive decay rates are constant [they are], 2) "fission tracks are produced with 100 percent efficiency" [laboratory experiments indicate they are], 3) the tracks are perfectly retained by the crystal [they are generally, but, for example, heat can anneal the material and shorten or eliminate the tracks]. The complete text concerning the fourth assumption, quoted directly from the Scientific American article follows:
"The fourth assumption presupposes that the concentration of uranium in any specimen has remained constant over the specimen's lifetime. This assumption is usually valid, but there can be exceptions. A combination of elevated temperatures and ground-water percolation can leach away a proportion of the uranium present in rock crystals. The mobility of the uranium is such that as one part of a rock formation is being impoverished another part can become abnormally enriched. Such changes can also take place at relatively low temperatures. Andrew J. W. Gleadow and John F. Lovering of the University of Melbourne have compared heavily weathered grains of apatite, a common mineral in rocks with unweathered grains still embedded in the parent rock. The weathered grains contained approximately 25 percent less uranium than those in the parent rock and yielded anomalous age determinations."
I am sure that the editor who prepared this material for the MIOS lecture had the comfort of the audience in mind when he eliminated the words "This assumption is usually valid, but there can be exceptions. A combination of elevated temperatures and ..." from the lecture materials. This part is particularly wordy, and it does break up the train of thought being developed. Nothing lost, however. Interested readers can stop by the library and read the complete article by J.D. Macdougall. This fascinating account outlines the theory and application of the fission track dating method which appears to be both robust and broadly applicable. For example, as described by the author, the technique has been used to provide a reliable date (2.0 +/- 0.3 million years) for a sedimentary stratum in the Olduvai Gorge, and it has also been used to determine that a supposed 18th-century Chinese glass ring was really a 70-year-old forgery.
In the second part of this story, we'll look at some claims MIOS makes for moon rock dating, and the dubious and deceptive schemes used to support their claims.
1) J.D. Macdougall, Scientific American 235 (6), 118