Meaning of Geological Age

What is Geological Age:

By "geological era" is understood a unit of time that serves to identify certain periods of conformation of the Earth.

The geological eras are part of the geochronological units, divided into epochs, periods, eras and eons according to the duration of each stage.

Thus, an eon contains eras, eras contain periods, and periods contain epochs.

The older the periodization (be it eon, era or period), the longer the span of time covered.

The best known geological eras are the closest to ours, and are part of the Phanerozoic eon. In turn, each of the eras contains different periods. Let's look at the periodization, ordered from the most recent to the oldest:

Geological eras in the Phanerozoic eon

It was Cenozoic

It is part of the Phanerozoic eon and spans from 65 million years to the present. It comprises the following subdivision:

  • Quaternary period.
  • Neogene period.
  • Palogenous period.

It was Mesozoic

It spans between 248 and 65 million years. The periods that make it up are:

  • Cretaceous period.
  • Jurassic period.
  • Triassic period.

Paleozoic era

It spans between 550 and 248 million years. It is made up of the following periods:

  • Permian period.
  • Carboniferous period.
  • Devonian period.
  • Silurian period.
  • Ordovician period.
  • Cambrian period.


The geological eras that are known today are part of the eons, and these in turn form supereons. The period known as Precambrian corresponds to the oldest supereon.

The Precambrian dates back to the origin of the earth 4.5 billion years ago and spans up to 500 million years ago. It encompasses the archaic and proterozoic eons.

From most recent to oldest we can order them as follows according to geological eras:

Neoproterozoic era

  • Ediacaran period.
  • Cryogenic period.
  • Tonic period.

It was Mesoproterozoic

  • Sthenic period.
  • Ectatic period.
  • Calimic period.

Paleoproterozoic era

  • Stateric period.
  • Gold period.
  • Riacic period.
  • Sidic period.

Within the Precambrian, the archaic eon is also included, made up of the Neoarchic, Mesoarchic, Paleoarchic and Eoarchic eras.

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