Steno four principles of relative dating

21 Jan

In a family like this it’s hard to tell how people are related simply by age. Early geologists had no way to determine the absolute age of a geological material.With rock units we use certain principles to tell their ages relative to each other. If they didn’t see it form, they couldn’t know if a rock was one hundred years or 100 million years old.Despite a relatively brief scientific career, Nicholas Steno's work on the formation of rock layers and the fossils they contain was crucial to the development of modern geology.The principles he stated continue to be used today by geologists and paleontologists.Remember Nicholas Steno, who determined that fossils represented parts of once-living organisms? Superposition refers to the position of rock layers and their relative ages (Figure below).

steno four principles of relative dating-59steno four principles of relative dating-58

Steno's idea that fossils are older than the rock in which they are found hints at this principle, but Hutton is most often given credit for this principle.states that fossil organisms succeed one another in a definite, irreversible, and determinable order.

The realization that sediments turn into rock was counter to the view that all rocks on Earth formed in a single creation event.

Once Steno recognized that the fossils he was contemplating (sharks teeth and sea shells) were formed in the sediments of oceans he was able to work out the basic rules of stratigraphy.

Early geologists had no way to determine the absolute age of a geological material. What they could do was determine the ages of materials relative to each other.

If they didn’t see it form, they couldn’t know if a rock was one hundred years or 100 million years old. Using sensible principles they could say whether one rock was older than another.