Geologic time scale
Geissman, John W. Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico.
Palmer, Allison R. Institute for Cambrian Studies, Boulder, Colorado.
Last reviewed:September 2018
Show previous versions
- Geologic time scale, published March 2016:Download PDF Get Adobe Acrobat Reader
- Geologic time scale, published June 2014:Download PDF Get Adobe Acrobat Reader
- Relative time scale
- Faunal succession
- Absolute time scale
- Carbon-14 dating
- Estimates and refinements
- Related Primary Literature
- Additional Reading
An ordered, internally consistent, internationally recognized sequence of time intervals, each distinct in its own history and record of life on Earth, including the assignment of absolute time in years to each geologic interval. The geologic time scale (see illustration) has two essential components: a relative scale, consisting of named intervals of geologic history arranged in chronologic sequence from oldest (bottom) to youngest (top); and a numerical (or absolute) time scale, providing estimates of absolute ages for the boundaries of these intervals.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information