That Roman pottery dating method everyone swears by let me down hard

I was working on a site near Bath last month and sent off some pottery samples for thermoluminescence dating, the gold standard technique everyone uses. Three different labs came back with results that were off by over 200 years compared to the stratigraphy we had already mapped out. I double checked everything, the sampling, the paperwork, even drove the samples myself to avoid shipping issues. Turns out the clay source had a much higher uranium content than the calibration assumed, which throws the whole thing sideways. Now I'm stuck telling the local museum their timeline is probably wrong and they aren't happy about it. Has anyone else had TL dating give you garbage numbers when the geology didn't fit the textbook?

2 comments

2 Comments

riley581d agoMost Upvoted

Right, the calibration curves assume a uniform background radiation that just doesn't hold up in certain spots, so it's basically the lab's baseline model being wrong. That uranium content messes with the whole signal, making the sample look way older or younger than it actually is, so the 200 year gap makes perfect sense from a physics standpoint. Hopefully the museum folks will respect the hard data once you walk them through the clay composition report?

patricia3851d ago

Oh man, that's a rough spot to be in after putting in all that careful work? I've been burned by calibration assumptions before too, it really makes you question everything when the lab results don't match what you see in the ground. Hope the museum folks come around when you show them the uranium evidence.