Optically stimulated luminescence OSL has only been used since It is very similar to thermoluminescence dating, both of which are considered "clock setting" techniques. The absolute dating method utilizing tree ring growth is known as dendrochronology. Radioactive decay dating is not a single method of absolute dating but instead a group of related methods for absolute dating of samples.
Potassium-argon dating has been used to date volcanic layers above and below fossils and artifacts in east Africa.
Radiocarbon dating is used to date charcoal, wood, and other biological materials.