No. 21: May-Jun 1982
Beds containing human artifacts at Valsequillo, Mexico, have been dated at approximately 250,000 years before the present by fission-track dating of volcanic material and uranium dating of a camel pelvis. The dilemma posed by such dates is clearly stated in the following quotation from the conclusions of the subject article.
"The evidence outlined here consistently indicates that the Hueyatlaco site is about 250,000 yr old. We who have worked on geological aspects of the Valsequillo area are painfully aware that so great an age poses an archeological dilemma. If the geological dating is correct, sophisticated stone tools were used at Valsequillo long before analogous tools are though to have been developed in Europe and Asia. Thus, our colleague, Cynthia Irwin-Williams, has criticized the dating methods we have used, and she wishes us to emphasize that an age of 250,000 yr is essentially impossible."
(Steen-McIntyre, Virginia, et al; "Geologic Evidence for Age of Deposits at Hueyatlaco Archeological Site, Valsequillo, Mexico," Quaternary Research, 16:1, 1981.)
Comment. The above impasse is reminiscent of Lord Kelvin's insistence that the earth is only about 100,000 years old based upon his calculations of the sun's energy-producing capabilities. Geologists thought otherwise, requiring roughly a billion years for nature to sculpt the earth they saw. Kelvin didn't reckon on nuclear energy, and the geologists had the last laugh!