Types of absolute dating
But the most accurate forms of absolute age dating are radiometric methods. Sedimentary rocks in particular are notoriously radioactive-free zones.
You might have noticed that many of the oldest age dates come from a mineral called zircon.
That’s because zircon is super tough – it resists weathering. Each radioactive isotope works best for particular applications.
The half-life of carbon 14, for example, is 5,730 years.
They do not provide “exact” dates for the materials.
Relative methods include stratigraphic correlation, which matches strata from different sites that are temporally comparable.