Four principles of stratigraphy give geologists ways to understand rock layers, including when and how they were created.
The Grand Canyon acts as a modern testament to stratigraphy and relative dating.
With out individual time stamps the process of dating these structures could become extremely difficult.
To deal with many of these problems geologists utilize two types of geologic time: relative time and absolute time.
Given the current status of direct chronometric dating methods for Arabian petroglyphs, it is rare that the precise age of a rock art panel can be determined.
However, all is not lost, and it is possible to establish a temporal sequence that can be quite edifying.
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.
With this in mind geologist have long known that the deeper a sedimentary rock layer is the older it is, but how old?
Although there might be some mineral differences due to the difference in source rock, most sedimentary rock deposited year after year look very similar to one another.
Geology, or the study of rocks, can be a fascinating way to learn about the Earth's history.
Relative dating is a key component to unlocking the mysteries of the Earth's past.
To progress, it is essential to apply the second type, or relative, dating.