A couple years ago, most anthropologists claimed that Homo sapiens first appeared in the Americas between 10,000 and 15,000 years ago.  In July of this year, a group of British scientists presented their own evidence that humans walked the New World as early as 40,000 years ago: footprints of both animals and hominids in a layer of volcanic ash.  The British team used "several methods" to date the footprints, chiefly carbon-14 dating on organic material found just above the ash layer.  "We have materials that have been dated below the footprint layer, the footprint layer itself and on top of the footprint layer. Everything is making sense," said Dr Silvia Gonzalez, leader of the British team who first discovered the tracks in 2003. 

 For the moment, never mind that creationists like myself don't generally believe the earth is older than 10,000 years.  Never mind that the 40,000-year-old date is based on only one site and with questionable dating techniques.  Never mind that the disparity in numbers above is 30,000 years, or, a 300% increase.

Enter Paul Renne from the Berkeley Geochronology Center in California.   Apparently Mr. Renne does't like the insinuation the tracks made--that humans came to the Americas 40,000 years ago.  After all, if that is correct, it flies in the face of the Clovis-First Model, which says humans migrated across the Bering Land Bridge into Alaska about 11,500 years ago.  If humans were here already, where did they come from?  Consequently, Mr. Renne decides to use argon-argon dating to test the ash deposits in which the footprints were found.  Argon-argon dating reads out 1.3 million years.  Mr. Renne smiles, because he knows that, according to evolutionary models, the oldest Homo sapiens fossils are only 160,000 years old.  "I'm totally unconvinced by the argument that they are footprints," concludes Renne, and publishes himself an article in the evolutionist-reviewed journal, Nature.

For the moment, never mind the other dating methods the British team used.  Never mind that this new argon-argon date is 1,260,000 years older, or about 3000% greater, than the other dates.

This situation just goes to show how wishy-washy "science" can be.  One minute you have in your hands the so-called missing link, and the next minute it's nothing but a funny-looking rock.  As for myself, I think both Gonzalez and Renne are incorrect, and overshoot the age of the ash layer.  I think the dating methods used by both teams are woefully unreliable.  I'm sympathetic towards the Clovis-First Model (though open to other theories), and I'm sympathetic towards the idea that the indentations you see here and here are indeed footprints.  I'm surprised at how tilted the ScienceDaily news story was against the British team.

To their credit, the Gonzalez team has posted a response to Renne and his Nature paper here.  They still think they've found human prints, and they say that they, too, used argon-argon dating on the prints, and "had no good results, and concluded that they were not reliable."  (Of course this means that the argon-argon dates were closer to Renne's results, and conflicted with the carbon-14 dates.)  They question the sample Mr. Renne actually tested, suggesting it was not from the prints themselves.  They also admit that Dr. Silvia Gonzalez "is one of a growing number of scientists who believes that the first Americans may have arrived by water rather than on foot, island hopping along the Pacific coast."

Isn't science fun?