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I thought carbon dating was always right until a lab tech in Flagstaff explained what a calibration curve actually does
I used to treat radiocarbon dates like a stamp from the universe, no arguing with it. Then I was reading up on a site in Arizona where two labs got results 400 years apart on the same charcoal sample, and a commenter pointed me to the calibration curves. Turns out raw carbon dates have to be matched against tree ring records, and in some chunks of history that correction shifts things a couple hundred years. I spent a whole weekend on the OxCal program just punching in random dates to watch how much they moved. Now when I see a dig report say "dated to 1200 BCE" I always scroll down to check if they gave a range and which curve they used. Anyone here ever had a date get thrown out or shifted after recalibration?
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emma_smith3h ago
Do you really believe a 400 year gap between labs means the whole method is shaky though? Labs mess up, samples get contaminated, charcoal from a hearth can come from old wood that was already centuries old when it got burned, so that spread might have nothing to do with the curves at all. Calibration is just math that turns a raw number into a calendar range and the curves are built from thousands of tree ring and coral samples that overlap and cross check each other, so its not like some guy in Flagstaff is just eyeballing it. Every method has error bars, that doesnt mean its broken, and a date with a 200 year range is still way better than guessing from pottery styles. Recalibration usually nudges dates by decades, not centuries, unless you were using a curve from the 1970s. The real problem isnt the science, its dig reports that drop a single year like "1200 BCE" and skip the range, which is on the writers, not on carbon dating.
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