---
title: "Geologic time scale"
chunk: 6/7
source: "https://en.wikipedia.org/wiki/Geologic_time_scale"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:18:29.061904+00:00"
instance: "kb-cron"
---

==== Van Kranendonk et al. 2012 (GTS2012) ====
The book, Geologic Time Scale 2012, was the last commercial publication of an international chronostratigraphic chart that was closely associated with the ICS and the Subcommission on Precambrian Stratigraphy. It included a proposal to substantially revise the pre-Cryogenian time scale to reflect important events such as the formation of the Solar System and the Great Oxidation Event, among others, while at the same time maintaining most of the previous chronostratigraphic nomenclature for the pertinent time span. As of April 2022 these proposed changes have not been accepted by the ICS. The proposed changes (changes from the current scale [v2023/09]) are italicised:

Hadean Eon (4567–4030 Ma)
Chaotian Era/Erathem (4567–4404 Ma) – the name alluding both to the mythological Chaos and the chaotic phase of planet formation.
Jack Hillsian or Zirconian Era/Erathem (4404–4030 Ma) – both names allude to the Jack Hills Greenstone Belt which provided the oldest mineral grains on Earth, zircons.
Archean Eon/Eonothem (4030–2420 Ma)
Paleoarchean Era/Erathem (4030–3490 Ma)
Acastan Period/System (4030–3810 Ma) – named after the Acasta Gneiss, one of the oldest preserved pieces of continental crust.
Isuan Period/System (3810–3490 Ma) – named after the Isua Greenstone Belt.
Mesoarchean Era/Erathem (3490–2780 Ma)
Vaalbaran Period/System (3490–3020 Ma) – based on the names of the Kaapvaal (Southern Africa) and Pilbara (Western Australia) cratons, to reflect the growth of stable continental nuclei or proto-cratonic kernels.
Pongolan Period/System (3020–2780 Ma) – named after the Pongola Supergroup, in reference to the well preserved evidence of terrestrial microbial communities in those rocks.
Neoarchean Era/Erathem (2780–2420 Ma)
Methanian Period/System (2780–2630 Ma) – named for the inferred predominance of methanotrophic prokaryotes
Siderian Period/System (2630–2420 Ma) – named for the voluminous banded iron formations formed within its duration.
Proterozoic Eon/Eonothem (2420–538.8 Ma)
Paleoproterozoic Era/Erathem (2420–1780 Ma)
Oxygenian Period/System (2420–2250 Ma) – named for displaying the first evidence for a global oxidising atmosphere.
Jatulian or Eukaryian Period/System (2250–2060 Ma) – names are respectively for the Lomagundi–Jatuli δ13C isotopic excursion event spanning its duration, and for the (proposed) first fossil appearance of eukaryotes.
Columbian Period/System (2060–1780 Ma) – named after the supercontinent Columbia.
Mesoproterozoic Era/Erathem (1780–850 Ma)
Rodinian Period/System (1780–850 Ma) – named after the supercontinent Rodinia, stable environment.
Proposed pre-Cambrian timeline (GTS2012), shown to scale:

ICC pre-Cambrian timeline (v2024/12, current as of January 2025), shown to scale:

== Extraterrestrial geologic time scales ==

Some other planets and satellites in the Solar System have sufficiently rigid structures to have preserved records of their own histories, for example, Venus, Mars and the Earth's Moon. Dominantly fluid planets, such as the giant planets, do not comparably preserve their history. Apart from the Late Heavy Bombardment, events on other planets probably had little direct influence on the Earth, and events on Earth had correspondingly little effect on those planets. Construction of a time scale that links the planets is, therefore, of only limited relevance to the Earth's time scale, except in a Solar System context. The existence, timing, and terrestrial effects of the Late Heavy Bombardment are still a matter of debate.

=== Lunar (selenological) time scale ===
The geologic history of Earth's Moon has been divided into a time scale based on geomorphological markers, namely impact cratering, volcanism, and erosion. This process of dividing the Moon's history in this manner means that the time scale boundaries do not imply fundamental changes in geological processes, unlike Earth's geologic time scale. Five geologic systems/periods (Pre-Nectarian, Nectarian, Imbrian, Eratosthenian, Copernican), with the Imbrian divided into two series/epochs (Early and Late) were defined in the latest Lunar geologic time scale. The Moon is unique in the Solar System in that it is the only other body from which humans have rock samples with a known geological context.

=== Martian geologic time scale ===
The geological history of Mars has been divided into two alternate time scales. The first time scale for Mars was developed by studying the impact crater densities on the Martian surface. Through this method four periods have been defined, the Pre-Noachian (~4,500–4,100 Ma), Noachian (~4,100–3,700 Ma), Hesperian (~3,700–3,000 Ma), and Amazonian (~3,000 Ma to present).

Epochs:

A second time scale based on mineral alteration observed by the OMEGA spectrometer on board the Mars Express. Using this method, three periods were defined, the Phyllocian (~4,500–4,000 Ma), Theiikian (~4,000–3,500 Ma), and Siderikian (~3,500 Ma to present).

== See also ==

== Notes ==

== References ==