Rock dating methods

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These demonstrate that, of course, we do not know everything (and clearly never will), but we know enough.Today, innovative techniques provide further confirmation and understanding of the history of life.The good dates are confirmed using at least two different methods, ideally involving multiple independent labs for each method to cross-check results.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.Methods fall into one of two categories: relative or absolute.Before more precise absolute dating tools were possible, researchers used a variety of comparative approaches called relative dating.Older dates may change by a few million years up and down, but younger dates are stable.For example, it has been known since the 1960s that the famous Cretaceous-Tertiary boundary, the line marking the end of the dinosaurs, was 65 million years old.

Every few years, new geologic time scales are published, providing the latest dates for major time lines.Our understanding of the shape and pattern of the history of life depends on the accuracy of fossils and dating methods.Some critics, particularly religious fundamentalists, argue that neither fossils nor dating can be trusted, and that their interpretations are better.Fossils document the order of appearance of groups and they tell us about some of the amazing plants and animals that died out long ago.Fossils can also show us how major crises, such as mass extinctions, happened, and how life recovered after them.

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