Absolute dating of a fossil
Current understanding of the history of life is probably close to the truth because it is based on repeated and careful testing and consideration of data.
Repeated, and tough, regimes of testing have confirmed the broad accuracy of the fossils and their dating, so we can read the history of life from the rocks with confidence. Educators have permission to reprint articles for classroom use; other users, please contact [email protected] reprint permission. Currently, he is studying certain basal dinosaurs from the Late Triassic and the quality of different segments of the fossil record.
He holds the Chair in Vertebrate Paleontology at the University of Bristol, UK, in addition to chairing the Masters program in paleobiology at the university.
A key point is that it is no longer necessary simply to accept one chemical determination of a rock’s age.
Age estimates can be cross-tested by using different isotope pairs.
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.
Early geologists, in the 1700s and 1800s, noticed how fossils seemed to occur in sequences: certain assemblages of fossils were always found below other assemblages. Since 1859, paleontologists, or fossil experts, have searched the world for fossils.
In the past 150 years they have not found any fossils that Darwin would not have expected.
If the fossils, or the dating of the fossils, could be shown to be inaccurate, all such information would have to be rejected as unsafe.