Three methods dating fossils
Instead, other methods are used to work out a fossil’s age.These include radiometric dating of volcanic layers above or below the fossils or by comparisons to similar rocks and fossils of known ages.Absolute dating is the process of determining an age on a specified chronology in archaeology and geology.Some scientists prefer the terms chronometric or calendar dating, as use of the word "absolute" implies an unwarranted certainty of accuracy.The atoms of some chemical elements have different forms, called isotopes.These break down over time in a process scientists call radioactive decay.Techniques include tree rings in timbers, radiocarbon dating of wood or bones, and trapped charge dating methods such as thermoluminescence dating of glazed ceramics.
Uranium is present in many different rocks and minerals, usually in the form of uranium-238.
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.
The rejection of the validity of fossils and of dating by religious fundamentalists creates a problem for them: Fossil sequences were recognized and established in their broad outlines long before Charles Darwin had even thought of evolution.
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.
New discoveries have filled in the gaps, and shown us in unimaginable detail the shape of the great ‘tree of life’.