Fossils may be dated by taking samples of rocks from above and below the fossil's original position.

Radiometric dating is also used to date archaeological materials, including ancient artifacts.

The method compares the amount of a naturally occurring radioactive isotope and its decay products, in samples. It is the main way to learn the age of rocks and other geological features, including the age of the Earth itself.

It may be used to date a wide range of natural and man-made materials.

The development of Atomic Absorption Mass Spectrometry in recent years, a technique that allows one to count the individual atoms of 14C remaining in a sample instead of measuring the radioactive decay of the 14C, has considerably broadened the applicability of radiocarbon dating because it is now possible to date much smaller samples, as small as a grain of rice, for example.

Dendrochronology is another archaeological dating technique in which tree rings are used to date pieces of wood to the exact year in which they were cut down.

It shows the age of the sample, and the original composition.

The method works best if neither the parent nuclide nor the daughter product enters or leaves the material after its formation.Techniques of recovery include: Data collection and analysis is oriented to answer questions of subsistence, mobility or settlement patterns, and economy.Radiometric dating (often called radioactive dating) is a way to find out how old something is.This principle presumes that the oldest layer of a stratigraphic sequence will be on the bottom and the most recent, or youngest, will be on the top.The earliest-known hominids in East Africa are often found in very specific stratigraphic contexts that have implications for their relative dating.The most commonly used chronometic method is radiocarbon analysis.