One method or relative dating
Unlike observation-based relative dating, most absolute methods require some of the find to be destroyed by heat or other means.This family of dating methods, some more than a century old, takes advantage of the environment’s natural radioactivity.Both plants and animals exchange carbon with their environment until they die.Afterward, the amount of the radioactive isotope carbon-14 in their remains decreases.Certain unstable isotopes of trace radioactive elements in both organic and inorganic materials decay into stable isotopes. By measuring the proportion of different isotopes present, researchers can figure out how old the material is.Here are some of the most common radiometric methods: Radiocarbon dating: Sometimes called carbon-14 dating, this method works on organic material.Researchers can first apply an absolute dating method to the layer.They then use that absolute date to establish a relative age for fossils and artifacts in relation to that layer. Anything below the Taupo tephra is earlier than 232; anything above it is later.
Researchers who work with prehistoric tools made from flint — a hardened form of quartz — often use thermoluminescence (TL) to tell them not the age of the rock, but of the tool.
Biostratigraphy: One of the first and most basic scientific dating methods is also one of the easiest to understand.