Compare and contrast relative dating and radioactive dating
Ice cores from Greenland and Antarctica show annual layers (varves) and can be traced up to about 40,000 years before the layers become too thin due to compaction.
C-14 dating of carbon-bearing materials is therefore limited to roughly 50,000 years.
Radioactive parent (P) atoms decay to stable daughter (D) atoms e.g.
the carbon isotope C-14 decays to nitrogen-14 and the uranium isotope U-235 decays to the lead isotope Pb-207.
Absolute dating supplies a numerical date whilst relative dating places events in time-sequence; both are scientifically useful.
This is based upon the spontaneous breakdown or decay of atomic nuclei.