How are cross cutting relationships used in relative dating
This matching process is called correlation, which has been an important process in constructing geological timescales.
Some fossils, called index fossils, are particularly useful in correlating rocks.
These techniques were first articulated by Nicolas Steno, a Dane living in the Medici court of Italy in the 17th C.
The most obvious feature of sedimentary rock is its layering.
Many of these organisms have left their remains as fossils in sedimentary rocks.
Geologists have studied the order in which fossils appeared and disappeared through time and rocks. Fossils can help to match rocks of the same age, even when you find those rocks a long way apart.
Fossils are important for working out the relative ages of sedimentary rocks.
Throughout the history of life, different organisms have appeared, flourished and become extinct.
With this in mind geologist have long known that the deeper a sedimentary rock layer is the older it is, but how old?Originally developed by James Hutton in Theory of the Earth (1795) and embellished upon by Charles Lyell in Principles of Geology (1830), the principle of cross-cutting relationships states that the geologic feature which cuts another is the younger of the two features.Cross-cutting relationships may be compound in nature.The method of reading the order is called stratigraphy (layers of rock are called strata).Relative dating does not provide actual numerical dates for the rocks.