Relative dating of geological features thedatingline com
Law of Superposition: The principle of superposition states that in a sequence of sedimentary rock layers, each layer must be younger than the one below, for a layer of sediment cannot accumulate unless there is already a substrate on which it can collect.
Thus, the layer at the bottom of a sequence is the oldest, and the layer at the top is the youngest.
It provides the geologic underpinning for the theory of evolution.
Example: Bed 1 at the base contains fossil species A, Bed 2 contains fossil species A and B, Bed 3 contains B and C, Bed 4 contains C, and so on.
The succession of events in order of relative age that have produced the rock, structure, and landscape of a region is called the geologic history of the region.
Fossil Succession As Britain entered the industrial revolution in the late 18th and early 19th centuries, new factories demanded coal to ﬁre their steam engines and needed an inexpensive means to transport goods.If sediments were deposited on a steep slope, they would likely slide downslope before they could be buried and lithified.With this principle in mind, geologists conclude that examples of folds and tilted beds represent the consequences of deformation after deposition.As we will see, painstaking work over many years eventually allowed geologists to assign numerical age ranges to fossil species.Of note, some fossil species are widespread, but survived only for a relatively short interval of geologic time.