Relative rock dating methods
Another way that precise dating can be achieved is if the artist records the actual date of his or her creation, the name of a leader of known reign, or a distinctive historical event, like the inscription shown in the previous chapter about King Yousif Assar Yathar’s invasion of the Najran region in 518 CE.Then, however, it must be clear that the artist is referring to his or her own time, and not providing historical commentary.The principle of superposition is defined as in the environment of an undisturbed layer of sedimentary rocks; the layers on the bottom are older than the layers towards the top.The pictures I have taken show very good examples of this.By using the principle of superposition we can know that the layers toward the bottom are older than the layers toward the top. Usually, the rock pieces, called sediments, drop from the wind or water to make a layer. The principle of superposition can also help give a relative date of any type of biological remnants that are contained in the layers.The rock body shown in the pictures attached, started out as one layer, as millions and millions of years passed more layers of sedimentary rock were placed on top of each other one after another, each layer was deposited at a later time than the one before it. The next principle that I am going to discuss is the principle of original horizontality.This type of dating tells us which geologic event happened first, but does not give an exact date to which something happened.There are several different methods that are used in relative dating.
The term refers to the fact that an approximate date can be inferred by comparison with something else of known age.
The youngest layer is on the top, and the oldest layer is on the bottom. This principle states that rocks are originally layered in horizontal planes, and any inclining area is caused by tilting of the rocks.
This principle was founded by the Danish anatomist Nicolas Steno, who noted that during floods, streams spread across their floodplains and deposit layers of sediment that bury organisms dwelling there. These gases attack the components of the rock and deposit new minerals in cavities and fissures. Steno came up with this principle also (Dutch 1998).
Relative dating methods are used to determine only if one sample is older or younger than another.
Absolute dating methods are used to determine an actual date in years for the age of an object.