Radioactive dating gold

What did two days of red-hot heating, pressure and treatment with hydrofluoric acid do to the samples? How can we be convinced this was “the big breakthrough” if an admirer admits he has no idea how it works?

How can we know the 79 he used were not also obviously too old, at least to someone without Darwin glasses on?(which, being translated, means “I have no idea if it works”). Remember, they are talking about “vanishingly small” bits of radioactive material to begin with, and then heating and acid-washing some of it away. But the way Kerr worded his subtitle, he sounds at best tentative about its benefits: “A new, apparently improved, way to date the greatest mass extinction points to a volcanic cause but fails to resolve geochronologists’ long-running differences.” (Emphasis added in all quotes.) Mundil’s team, from the Berkeley Geochronology Center, admits right off that “The age and timing of the Permian-Triassic mass extinction have been difficult to determine because zircon populations from the type sections are typically affected by pervasive lead loss and contamination by indistinguishable older xenocrysts.” In order to date samples from China, they “adopted a technique recently developed by James Mattinson of the University of California, Santa Barbara, Kerr says.“ They baked the southern China zircons at 850�C for 36 hours and then leached them with hydrofluoric acid under pressure at 220�C for 16 hours, with the intention of removing the parts most weakened by radiation damage.” This harsh treatment of the samples was intended to eliminate some of the “picking and choosing” that commonly goes on by researchers, who discard samples that don’t give them the results they expect.

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