This method is based on the assumption (which nearly always holds true) that deeper layers of rock were deposited earlier in Earth's history, and thus are older than more shallow layers.The successive layers of rock represent successive intervals of time.
An example of this type of aging includes rocks in Canada that scientists identified as being hundreds of million years old.
Absolute age is more straight-forward and does not require any other objects for comparison.
Dating techniques are procedures used by scientists to determine the age of an object or a series of events.
The two main types of dating methods are relative and absolute.
Relative age allows scientists to know whether something is older or younger than something else, while absolute age means that scientists know the exact number in years that have passed since the object was created.
Relative age will require the comparison of two or more objects, whereas absolute age does not.
Since certain species of animals existed on Earth at specific times in history, the fossils or remains of such animals embedded within those successive layers of rock also help scientists determine the age of the layers.
Similarly, pollen grains released by seed-bearing plants became fossilized in rock layers.
Imagine that throughout your life youve taken many pictures. Certain groups of fossil animals and plants occur in the geologic record in a specific order.