Geologic Time (History) Geologic history can be divided into five great Eras of recorded time. These Eras and approximate time periods include: 1 Archeozoic 4,500 million years ago (MYA) to 3,500 MYA, 2 Proterozoic (or Prepaleozoic) 3,500 MYA to 586 MYA, 3 Paleozoic 570 MYA to 230 MYA, 4 Mesozoic 230 MYA to 65 MYA, and 5 Cenozoic 65 MYA to present. Each time Era (except the first) is divided into Periods (e.g., the Cenozoic into the Quaternary and the Tertiary) and Periods are further divided into Epochs (e.g., the Tertiary into the Pliocene, Miocene, Oligocene, Eocene, and the Paleocene). For each time period, whether an Era, Period, or Epoch, there is a corresponding rock formation by which the time period has been dated. Rock formations constituting a specific (time) Era form a Group of rocks, those rocks having been formed during a specific (time) Period constitute a rock System, and those rock formations originating during a specific (time) Epoch are said to belong to a particular Series of rocks. Series of rock formations are further subdivided into Formations, Stages, etc. See Appendix F-1, Geologic Time Chart.
Source: http://www.bvsde.paho.org/bvsacg/i/fulltext/dicciona/dicciona.pdf
Web site to visit: http://www.state.nv.us/cnr/ndwp/home.htm
Author of the Water Words Dictionary source of text: Gary A. Horton
If you are the author of the text above and you not agree to share your knowledge for teaching, research, scholarship (for fair use as indicated in the United States copyrigh low) please send us an e-mail and we will remove your text quickly. Fair use is a limitation and exception to the exclusive right granted by copyright law to the author of a creative work. In United States copyright law, fair use is a doctrine that permits limited use of copyrighted material without acquiring permission from the rights holders. Examples of fair use include commentary, search engines, criticism, news reporting, research, teaching, library archiving and scholarship. It provides for the legal, unlicensed citation or incorporation of copyrighted material in another author's work under a four-factor balancing test. (source: http://en.wikipedia.org/wiki/Fair_use)
The information of medicine and health contained in the site are of a general nature and purpose which is purely informative and for this reason may not replace in any case, the council of a doctor or a qualified entity legally to the profession.
The following texts are the property of their respective authors and we thank them for giving us the opportunity to share for free to students, teachers and users of the Web their texts will used only for illustrative educational and scientific purposes only.
All the information in our site are given for nonprofit educational purposes
The information of medicine and health contained in the site are of a general nature and purpose which is purely informative and for this reason may not replace in any case, the council of a doctor or a qualified entity legally to the profession.
www.riassuntini.com