Relative geologic dating and numerical geologic dating
Relative time was determined long before absolute time.Index fossils are often used to determine a specific era.Relative Time Relative time is the sequence of events without consideration of the amount of time.
Source (text and graphic): University of Calgary, Geology and Geophysics Department.
To be a good index fossil, the species should: Using index fossils, geologists were able to correlate across Europe, and then to other continents.
Reference Websites For more information about relative geological time check out the USGS website:
Earth Science Week Editor's Note: As terms, Tertiary subdivisions Paleogene and Neogene have gained favor relatively recently.
Older literature divides the Tertiary into epochs (from oldest to newest): Paleocene, Eocene, Oligocence, Miocene, and Pliocene.Revisions to the relative time scale have occurred since the late 1700s.