( The rocks do not date the fossils the fossils date the rocks American Journal of Science Jan 1976 47-55) Absolute dating is based on radioactivity.
Relative dating is based on super imposition and fossils.
While in the absolute dating, isotopes of carbon are used for dating fossils.
Scientific American Oct 1980 156-168 The rocks on the surface of the southern Appalachians are older than the sedimentary layers under them.
Absolute dating(also known as radiometric dating) is based by the measurement of the content of specific radioactive isotopes of which the "half time" is known.
Half time is the time needed for half of a given quantity of an isotope to decay in its byproducts.
This is the basis of relative dating Fossils Out of Sequence Palaios June 1990 page 227 "We define stratigraphic disorder as the departure from perfect chronological order of fossils in a stratigraphic sequence, in which an older fossils occurs above a younger one. stratigraphic disorder at some scale is probably a common feature of the fossil record.
Pragmatism verus Materialism American Journal of Science Jan 1976 page 54-55 Fossils date rocks not vice[versa and that's that.