Isotope dating fossils
This technique relies on the property of half-life.
Half-life is defined as the time it takes for one-half of a radioactive element to decay into a daughter isotope.
The half-lives of several radioactive isotopes are known and are used often to figure out the age of newly found fossils.
[SE] K-Ar is just one of many isotope-pairs that are useful for dating geological materials.
C) can be applied to many geological materials, including sediments and sedimentary rocks, but the materials in question must be younger than 60 ka.
Fragments of wood incorporated into young sediments are good candidates for carbon dating, and this technique has been used widely in studies involving late Pleistocene glaciers and glacial sediments.
A clastic sedimentary rock is made up of older rock and mineral fragments, and when the rock forms it is almost certain that all of the fragments already have daughter isotopes in them.
Furthermore, in almost all cases, the fragments have come from a range of source rocks that all formed at different times.