The Wheeler Formation has been previously dated to approximately 507 million year old, so we know the trilobite is also about 507 million years old.
But, how can we determine how old a rock formation is, if it hasn’t previously been dated?
Using relative dating the fossil is compared to something for which an age is already known.
For example if you have a fossil trilobite and it was found in the Wheeler Formation.
The style of the artefact and its archaeology location stratigraphically are required to arrive at a relative date.
For example, if an artefact, say an oil lamp, is found co-located on the same floor of a governor's dwelling, and that floor can be dated in archaeology terms by reason of the patterns employed in the mosaic, then it is assumed that in relation to the floor that the lamp is of the same age.
In other words, artifacts found in the upper layers of a site will have been deposited more recently than those found in the lower layers.
Cross-dating of sites, comparing geologic strata at one site with another location and extrapolating the relative ages in that manner, is still an important dating strategy used today, primarily when sites are far too old for absolute dates to have much meaning.
Archaeological scientists have two primary ways of telling the age of artefacts and the sites from which they came: relative dating and absolute dating.Relative dating in archaeology presumes the age of an artefact in relation and by comparison, to other objects found in its vicinity.Limits to relative dating are that it cannot provide an accurate year or a specific date of use.New dating methods are invented all the time, however, most have practical limitations.Geologic research and mapping requires the determinations of the ages and composition of rocks.