Uses mass spectrometry radioactive dating
Overview of Methods Superposition Stratigraphy Dendrochronology Radiocarbon C14 Radiometric Dating Methods Obsidian Hydration Dating Paleomagnetic/Archaeomagnetic Luminescence Dating Methods Amino Acid Racemization Fission-track Dating Ice Cores Varves Pollens Corals Cation Ratio Fluorine Dating Patination Oxidizable Carbon Ratio Electron Spin Resonance Cosmic-ray Exposure Dating This is an excellent overview of dating methodologies, and is a chapter in a textbook on Archaeology.
You may find it useful for the clear definitions, and for excellent links on a variety of topic.
Hutton, a Scottish geologist, first proposed formally the fundamental principle used to classify rocks according to their relative ages.
He concluded, after studying rocks at many outcrops, that each layer represented a specific interval of geologic time.
There, you will find a brief description of the method, plus links to take you to other webpages with more extensive information.
The Carbon14 technique has been and continues to be applied and used in many, many different fields including hydrology, atmospheric science, oceanography, geology, palaeoclimatology, archaeology and biomedicine. Isochron methods avoid the problems which can potentially result during radiometric testing.
Be sure to see An Animated Isochron Diagram, or, Watching a Rock Age on an Isochron Diagram. Radiometric Dating from The Evolution Evidence Page.
Using these key or index fossils as markers, Smith could identify a particular layer of rock wherever it was exposed.
Because fossils actually record the slow but progressive development of life, scientists use them to identify rocks of the same age throughout the world.