However, the assumption of contemporaneity may not always be correct.
This is due to the fact that one or both of the objects may have been moved or redeposited into a different location.
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.
Dating techniques are procedures used by scientists to determine the age of an object or a series of events.
The two main types of dating methods are relative and absolute.
These processes result in All of these processes confuse the stratigraphic record.
As a result, it was difficult to chronologically compare fossils from different parts of the world.
Stratigraphy is the oldest of the relative dating methods that archaeologists use to date things.
Stratigraphy is based on the law of superposition--like a layer cake, the lowest layers must have been formed first.
The laws of physics and chemistry that governed geologic processes in the past are the same as those that govern processes now and in the future.
The geologic timescale is a chronology (calendar) of events on Earth based on obtaining ages of past events.