Earth dating techniques

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.

Biologists actually have at their disposal several independent ways of looking at the history of life - not only from the order of fossils in the rocks, but also through phylogenetic trees. Relative dating is done by observing fossils, as described above, and recording which fossil is younger, which is older.

The discovery of means for absolute dating in the early 1900s was a huge advance.

Other critics, perhaps more familiar with the data, question certain aspects of the quality of the fossil record and of its dating.

These skeptics do not provide scientific evidence for their views.

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.

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.

New discoveries have filled in the gaps, and shown us in unimaginable detail the shape of the great ‘tree of life’.

Darwin and his contemporaries could never have imagined the improvements in resolution of stratigraphy that have come since 1859, nor guessed what fossils were to be found in the southern continents, nor predicted the huge increase in the number of amateur and professional paleontologists worldwide.

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.

Geologists and paleontologists are highly self-critical, and they have worried for decades about these issues. D., is a vertebrate paleontologist with particular interests in dinosaur origins and fossil history.

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.

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.

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