Mathods of dating
Unlike observation-based relative dating, most absolute methods require some of the find to be destroyed by heat or other means.
This family of dating methods, some more than a century old, takes advantage of the environment’s natural radioactivity.
Researchers who work with prehistoric tools made from flint — a hardened form of quartz — often use thermoluminescence (TL) to tell them not the age of the rock, but of the tool.Sometimes only one method is possible, reducing the confidence researchers have in the results. “They’re based on ‘it’s that old because I say so,’ a popular approach by some of my older colleagues,” says Shea, laughing, “though I find I like it myself as I get more gray hair.” Kidding aside, dating a find is crucial for understanding its significance and relation to other fossils or artifacts.