When these regions are later exposed in uptilted portions of ancient continents, a history of terrestrial rock-forming events can be deduced.Episodes of global has had a profound impact on the scientific understanding of our dynamic planet.Some method of correlating rock units must be found.
Similarly, in geologic studies, vast quantities of information from widely spaced outcrops have to be integrated.
For example, the presence of recycled bricks at an archaeological site indicates the sequence in which the structures were built.
Similarly, in geology, if distinctive granitic pebbles can be found in the sediment beside a similar granitic body, it can be inferred that the granite, after cooling, had been uplifted and eroded and therefore was not injected into the adjacent rock sequence.
Any feature, including colour variations, textures, fossil content, , or any unusual combinations of these can be used.
It is only by correlations that the conditions on different parts of Earth at any particular stage in its history can be deduced.