Potassium argon is an example of a relative dating technique
But absolute dating methods are not always useful; the particular circumstances to which they apply do not exist at every site.
Dating methods, such as radiocarbon dating, dendro-chronology or tree-ring dating, and potassium-argon dating, that may furnish an date for an archaeological site, are a contribution of the physical and the natural sciences.
In such cases, archaeologists may employ , with the older layer beneath the latest.
The top of the heap of excavated dirt would date the oldest.Or perhaps a burrowing animal tunneled down through a site, causing artifacts buried above to fall to lower levels.Natural processes like frost heaving, erosion, and the down-slope movement of soils in colder climates (solifluction) can alter the original context in which the artifacts were deposited.Stratigraphic levels can be horizontal as well as vertical.On beaches, where the configuration of the shoreline has changed through time, the earliest site may be inland, the later site closest to shore.