Stratigraphic column dating

19-Oct-2019 07:55

Correlation based on the physical features of the rock record also has been used with some success, but it is restricted to small areas that generally extend no more than several hundred kilometres.The first step is determining whether similar beds in separated outcrops can actually be traced laterally until they are seen to be part of the same original layer.Furthermore, useful fossils are either rare or totally absent in rocks from Precambrian time, which constitutes more than 87 percent of Earth history.

Almost without exception, the relative order of strata defined by fossils has been confirmed by radiometric ages.

Applying the principle of superposition, we know that Stratum A was deposited after Stratum B, Stratum B was deposited after Stratum C, and so on.