The two methods are "RELATIVE DATING" and "ABSOLUTE DATING". :)
Index fossils
death
relative and absolute. relative is determining the relative order of past events, without necessarily determining their absolute age. Absolute is the process of determining an approximate computed age in archaeology and geology.
Index
Perhaps by carbon dating and by comparing with the evolution and dominance of various organisms in the geological time scale.
Determining the ages of igneous rocks helps to establish the age of the rock layer in which fossils are found. By dating the igneous rocks above and below the fossil-containing layer, scientists can narrow down the possible age range of the fossils found within that layer. This helps to provide a more accurate estimate of the fossil's age.
Index fossils, which are geographically widespread, of a quickly evolving specie, and only present in sedimentary strata of a particular geologic age, are generally reliable in setting a general time range for the age of a rock specimen.
Relative dating is the science determining the relative order of past events, without necessarily determining their absolute age Absolute dating is the process of determining an approximate computed age in archaeology and geology.
Two ways to date fossils are relative dating, which involves determining the age of a fossil in relation to other fossils or geological layers, and absolute dating, which provides a numerical age for a fossil using techniques like radiometric dating.
Geologists look for index fossils in the sedimentary rock to help determine its age. Index fossils are of organisms that were widespread and only existed during a specific slice of geologic time. Finding an index fossil in a rock means that the rock dates to that specific slice of time.
Geologists use fossils to determine the age of rocks through a process called biostratigraphy. They identify the specific group of fossils present in the rock layer, known as index fossils, that have a known age range. By comparing the index fossils to a geological time scale, geologists can estimate the age of the rock layer.
Graptolites are excellent index fossils because they have a short-lived existence in the geologic time scale and are widespread. They are useful for dating rocks and correlating layers in different locations, assisting in determining the age of rocks and reconstructing past environments.