Era (geology)
Get Era Geology essential facts below. View Videos or join the Era Geology discussion. Add Era Geology to your topic list for future reference or share this resource on social media.
Era Geology

A geologic era is a subdivision of geologic time that divides an eon into smaller units of time.[1] The Phanerozoic Eon is divided into three such time frames: the Paleozoic, Mesozoic, and Cenozoic (meaning "old life", "middle life" and "recent life") that represent the major stages in the macroscopic fossil record. These eras are separated by catastrophic extinction boundaries: the P-T boundary between the Paleozoic and the Mesozoic, and the K-Pg boundary between the Mesozoic and the Cenozoic.[2] There is evidence that catastrophic meteorite impacts played a role in demarcating the differences between the eras.

The Hadean, Archean and Proterozoic eons were as a whole formerly called the Precambrian. This covered the four billion years of Earth history prior to the appearance of hard-shelled animals. More recently, however, the Archean and Proterozoic eons have been subdivided into eras of their own.

Geologic eras are further subdivided into geologic periods, although the Archean eras have yet to be subdivided in this way.[3]

List of geological eras in Earth's history

See also


  1. ^ "Chapter 9. Chronostratigraphic units". Stratigraphic guide. International Commission on Stratigraphy. Retrieved 2018.
  2. ^ Erwin D.H. (1994). "The Permo-Triassic Extinction" (PDF). Nature. 367 (6460): 231-236. doi:10.1038/367231a0. S2CID 4328753.
  3. ^ International Commission on Stratigraphy. "International Chronostratigraphic Chart v2018/07" (PDF). Retrieved 2018.

  This article uses material from the Wikipedia page available here. It is released under the Creative Commons Attribution-Share-Alike License 3.0.



Music Scenes