ICS chart v2026/06 · official colours
Geologic time scale
The geologic time scale splits Earth's history into eons, eras, periods, epochs and ages. This is the International Commission on Stratigraphy's chart, version 2026/06: choose any band to zoom in, or type an age to see where it falls. The Jurassic, for example, ran from 201.4 ± 0.2 to 143.1 ± 0.6 million years ago.
The chart Youngest at the top; ages in millions of years ago (Ma)
Choose any band to zoom in and see its dates. The breadcrumb above the chart zooms back out.
How to read the chart
Each column is one rank, from the longest (eons) on the left to the shortest (ages) on the right, and each band is coloured with the official colour the chart uses, which follows the Commission for the Geological Map of the World. Choose a band to zoom to it, or pick any unit from the Zoom to menu under the chart; the breadcrumb above the chart steps back out.
- ± numbers are the uncertainty of a boundary's age, as printed on the chart. A “~” marks an approximate boundary that has not yet been fixed precisely.
- How old is it? finds every unit an age falls in. An age exactly on a boundary counts as the start of the younger unit, and the finder warns you when an age is within a boundary's uncertainty.
- The chart starts at 4,567 million years ago, the age of the Solar System's oldest solids. The Earth itself is 4.54 billion years old, uncertain by less than 1 percent (USGS).
Sources
- International Commission on Stratigraphy. International Chronostratigraphic Chart v2026/06 (June 2026), stratigraphy.org/chart, and its data file chart.ttl (version 2026-06) at github.com/i-c-stratigraphy/chart. Cite as Cohen KM, Harper DAT, Gibbard PL, Car N. 2025. The ICS International Chronostratigraphic Chart this decade. Episodes 48:105–115, doi:10.18814/epiiugs/2025/025001. Where the data file and the printed chart differ (the base of the Aquitanian, the uncertainty of the base of the Silurian), this page follows the printed chart.
- USGS. Age of the Earth. pubs.usgs.gov/gip/geotime/age.html.
- Life highlights: each one names its source beside it, from the UC Museum of Paleontology, the British Geological Survey, the Florida Museum, the Smithsonian, the Charmouth Heritage Coast Centre and peer-reviewed papers.
Questions
What are the main divisions of the geologic time scale?
Eons, split into eras, then periods, epochs and ages. We live in the Phanerozoic Eon, Cenozoic Era, Quaternary Period, Holocene Epoch and Meghalayan Age.
When did the dinosaurs die out?
At the end of the Cretaceous, 66.00 million years ago, the boundary between the Mesozoic and Cenozoic eras on the ICS chart.
How old are the rocks of the Jurassic Coast?
They record about 185 million years of the Triassic, Jurassic and Cretaceous periods, says the Charmouth Heritage Coast Centre. The cliffs at Charmouth were laid down around 195 million years ago.