Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
Proterozoic Eon
References & Edit History Related Topics
Images
A chart showing the Proterozoic eon on the geologic time scale, divided into Paleoproterozoic, Mesoproterozoic, and Neoproterozoic eras with their respective periods and the millions of years ago each period began, ranging from 2,500 to about 539 million years ago. Two diagrams compare Earth's prebiotic and modern atmospheres. The top shows a barren landscape with gases like hydrogen, nitrogen, carbon dioxide, and ammonia labeled above, indicating a weakly reducing atmosphere. The bottom shows a lush landscape with plants and animals, labeling oxygen, argon, and other gases, illustrating an oxidizing modern atmosphere. A detailed geologic time scale chart displaying Earth's history from the Hadean Eon over 4.5 billion years ago to the present, organized by eons, eras, periods, epochs, and ages with color-coded columns and corresponding dates in millions of years. Major events of the Neoproterozoic Era Cutaway diagram of a Grand Canyon wall showing layered sedimentary rocks-limestone, shale, sandstone, and composite rocks-with labels indicating Paleozoic rocks (about 252-541 million years old) above older Precambrian rocks, which include Proterozoic (541 million to 2.5 billion years old) and Archean (over 2.5 billion years old) layers. The Colorado River is shown at the base.
At a Glance
default image
Proterozoic Eon summary
Related Questions

Proterozoic Eon: References & Edit History

Article Contributors

Primary Contributors

  • Brian Frederick Windley
  • The Editors of Encyclopaedia Britannica
    Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.

Other Encyclopedia Britannica Contributors

Article History

Type Description Contributor Date
Added illustration. Nov 11, 2025
Added cross-references. Jan 27, 2023
Article revised and updated. Aug 02, 2021
Invalidated site: University of California, Berkeley: Museum of Paleontology - Introduction to the Proterozoic Era. May 06, 2014
Text added that updates the interval's boundary years. May 17, 2013
Proterozoic geologic time chart added. Jan 27, 2010
Article revised and updated. Apr 25, 2007
Added new Web site: University of California Museum of Paleontology - Proterozoic Era. Jan 10, 2007
Added new Web site: University of California, Berkeley: Museum of Paleontology - Introduction to the Proterozoic Era. Jun 26, 2006
Article added to new online database. Jul 20, 1998
View Changes:
Article History
Revised:
By: