Finally gave up on carbon dating after talking to a professor at UNM

I used to think carbon-14 dating was the gold standard for everything ancient, but a professor at University of New Mexico explained how contamination from groundwater can shift dates by thousands of years. He showed me a sample from a site in Chaco Canyon that tested 800 years older than it actually was because of root intrusion. Now I'm looking more at dendrochronology for southwestern sites. Has anyone else run into issues with dating methods giving false results from environmental factors?

2 comments

2 Comments

blairj5523d ago

So did he offer to carbon date your skepticism too?

charlie_allen23d ago

That UNM professor might be right about contamination issues but I'd push back hard on giving up on carbon dating entirely. They caught a bad sample from Chaco Canyon and now you're tossing out a method that's been cross-checked against tree rings for thousands of years. Ice cores from Greenland and lake varves in Sweden line up perfectly with radiocarbon curves going back 13,000 years. A single contaminated root sample doesn't break the whole system any more than a flat tire means your truck is junk. Volcanic ash layers in the Southwest also match carbon dates within a hundred years or so at most sites. Stick with multiple methods instead of swinging to dendrochronology as the only answer.