Some of the most useful fossils for dating purposes are very small ones.For example, microscopic dinoflagellates have been studied and dated in great detail around the world.
Relative dating methods are unable to determine the absolute age of an object or event, but can determine the impossibility of a particular event happening before or after another event of which the absolute date is well known.
In this relative dating method, Latin terms ante quem and post quem are usually used to indicate both the oldest and the most recent possible moments when an event occurred or an artifact was left in a stratum.
This is admitted because of the simple reason that some botanical species, whether extinct or not, are well known as belonging to a determined position in the scale of time.
For a non-exhaustive list of relative dating methods and relative dating applications used in geology, paleontology or archaeology, see the following: Same as geologists or paleontologists, archaeologists are also brought to determine the age of ancient materials, but in their case the areas of their studies are restricted to the history of both ancient and recent humans.
Different species of ammonites lived at different times within the Mesozoic, so identifying a fossil species can help narrow down when a rock was formed.
Correlation can involve matching an undated rock with a dated one at another location.
Nevertheless, the range of time within archaeological dating can be enormous compared to the average lifespan of a singular human being.
As an example Pinnacle Point's caves, in the southern coast of South Africa, provided evidence that marine resources (shellfish) have been regularly exploited by humans as of 170,000 years ago.
This usually requires what is commonly known as a "dating method".
Several dating methods exist, depending on different criteria and techniques, and some very well known examples of disciplines using such techniques are, for example, history, archaeology, geology, paleontology, astronomy and even forensic science, since in the latter it is sometimes necessary to investigate the moment in the past in which the death of a cadaver occurred.
But this method is also useful in many other disciplines.