At death, the exchange stops, and the carbon-14 then decays with a known half-life, which enables scientists to calculate the time of death.
However, it quickly became clear that something wasn’t quite right.

For example if you have a fossil trilobite and it was found in the Wheeler Formation.
The Wheeler Formation has been previously dated to approximately 507 million year old, so we know the trilobite is also about 507 million years old.
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.
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.
With the help of new physical and chemical dating methods, scientists are finally beginning to discover how and when archaic species became…
well, us.‘The great breakthrough in Quaternary archaeology was radiocarbon dating,’ Walker says.
In the past 150 years they have not found any fossils that Darwin would not have expected.
New discoveries have filled in the gaps, and shown us in unimaginable detail the shape of the great ‘tree of life’.
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For example, the correlation of soil series, rock units, fluvial terraces or glacial moraines give a chronology of geologic events relative to one and other.