Absolute vs relative dating techniques
Sedimentary rocks are rarely useful for dating because they are made up of bits of older rocks.
Uranium is present in many different rocks and minerals, usually in the form of uranium-238.
Using relative dating the fossil is compared to something for which an age is already known.
For example if you have a fossil trilobite and it was found in the Wheeler Formation.
Since relative dating can easily be verified by superposition (the younger bed over the older one), intrusion (the intrusive being younger than the intrusive rock), and use of index fossils (younger fossils in a rock layer make that layer younger than another containing older fossils), relative dating can be confirmed right at the field using one's direct observation.
Absolute dating methods are used to determine an actual date in years for the age of an object.
There are two main methods determining a fossils age, relative dating and absolute dating.
Relative dating is used to determine a fossils approximate age by comparing it to similar rocks and fossils of known ages.
Before the advent of absolute dating methods in the twentieth century, nearly all dating was relative.
The main relative dating method is stratigraphy (pronounced stra-TI-gra-fee), which is the study of layers of rocks or the objects embedded within those layers.Dating techniques are procedures used by scientists to determine the age of an object or a series of events.