At the beginning detected by Nicholas Steno in the 17th century, the Law of Superposition affirms that in an uninterrupted series of sedimentary rocks, the oldest rocks will be underneath and the new rocks will be at the top.
It asserts that in a classification of sedimentary rock layers, the oldest rocks are at the bottom, except the layers have been upturned by tectonics. Superposition is one of the basic concepts of sedimentary geology and permitted geologists to find out the relative ages of beds in an order of sedimentary rocks.
The law of superposition is a saying that creates one of the foundations of the sciences of geology, archaeology, and other fields dealing with geological stratigraphy. It is a type of relative dating. In its natural form, it asserts that in undeformed stratigraphic orders, the oldest rocks will be at the bottom of the chain.
The law of superposition is based on the rational argument that the underneath layer had to set down first. The underside layer as it reasonably had to be laid down first must be older. The layers on top could only be laid down on top of the bottom layer so it must be newest.
Still, the relative ages of rocks are more usually ascertained by the supposed ages of the fossils created in the sedimentary layers. The sedimentary layers with the simplest fossils are supposed to be older even if the sedimentary layer is found on top of a sedimentary layer that has fossils that are denser and therefore understood to be younger.
Fossils that are in contravention of the law of superposition where the older fossil happens above a younger fossil are said to be stratigraphically disarrayed. Nearly, all sedimentary systems have stratigraphic disarray at come scale is perhaps a usual feature of the fossil record.
The superposition principle affirms that when two or more waves overlie in space, the follow-on commotion is identical to the algebraic sum of the individual disorders. This is at times contravened for large disorders like non-linear interactions.
The Law of Superposition makes reasonable sense but in practice, it is the nature of the fossils found in the sedimentary layers that resolve the relative ages of the rocks. The theory of descent with modification trumps the experiential confirmation of superposition.
Superposition process in archaeology and in particular in stratification used in the dig is a little different as the processes concerned in laying down archaeological strata are fairly different from geological development.