Geologic era

From Glossary of Meteorology
(Redirected from Geologic eras)

geologic era

The primary and largest division of geologic time.

Limits correspond with major, global crustal events, changes in sea level and/or climate, or biotic changes. Five geologic eras have been established: Archeozoic [before 2500 million years ago (Ma)], Proterozoic (2500 to 570 Ma), Paleozoic (570 Ma to ca. 250 Ma), Mesozoic (ca. 250 to ca. 70 Ma), and Cenozoic (since ca. 70 Ma). All eras are divided into at least two geologic periods.

Copyright 2022 American Meteorological Society (AMS). For permission to reuse any portion of this work, please contact Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act (17 U.S. Code § 107) or that satisfies the conditions specified in Section 108 of the U.S.Copyright Act (17 USC § 108) does not require AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, require written permission or a license from AMS. Additional details are provided in the AMS Copyright Policy statement.