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The Cenozoic, Mesozoic, and Paleozoic are the Eras of the Phanerozoic Eon. Names of units and age boundaries usually follow the Gradstein et al. (2012), Cohen et al. (2012), and Cohen et al. (2013, updated) compilations.
The Geologic Time Scale is divided into four eons, ten eras, 22 periods, and several epochs and ages. Each eon, era, period, and epoch is defined by major geological or paleontological events. The eons are the Hadean, Archean, Proterozoic, and Phanerozoic.
The geologic time scale is divided into chronostratigraphic units and their corresponding geochronologic units. An eon is the largest geochronologic time unit and is equivalent to a chronostratigraphic eonothem. [13] There are four formally defined eons: the Hadean, Archean, Proterozoic and Phanerozoic. [2]
Versioned charts and detailed information on ratified GSSPs are available at the website http://www.stratigraphy.org. The URL to this chart is found below. Numerical ages are subject to revision and do not define units in the Phanerozoic and the Ediacaran; only GSSPs do.
6 gru 2023 · Each unit of time is defined by specific events and changes that took place on Earth, such as the formation of the planet, the evolution of life, and mass extinctions. The two eons in the Geologic Time Scale are the Precambrian eon and the Phanerozoic eon.
The Geologic Time Scale is divided into four major units: Eons, Eras, Periods and Epochs. An Eon is the longest division of geologic time, so long in fact that there have only been four Eons.
You can browse the timechart by geological era in the page below or download the Phanerozoic Timechart as a pdf. The BGS geological timechart is based on The Geologic Time Scale 2012 . BGS © UKRI.
