geological time

Geologists have based geological timelines on significant events in Earth history, as a result the named geological intervals are not of equal length.

Eons are the longest intervals (hundreds of millions of years) and are subdivided into eras, which are further subdivided into periods, and still further subdivided into epochs.
mnemonics

By convention: Precambrian Eons are:
The Hadean Eon, which extends from Earth's formation to 3.8 billion years ago (Ga) is succeeded by the Archean Eon (not to be confused with prokaryotic Archaea), which lasts until 2.5 Ga. The Proterozoic Eon next extends from 2.5 billion years ago to 543 million years ago.

From 543 million years ago to the present geological time is classified as the Phanerozoic (visible life) Eon, and the eon opens with the Cambrian Period.

Geological Society of America time scale - pdf
Geologic Time Scale from International Commission on Stratigraphy
Geologic Time Scale - University of California Berkeley
Geologic Time Scale - US Geological Survey
Paleontology and the Geologic Time Scale - US Geological Survey

PaleoMaps Precambrian Cambrian Ordovician Silurian Devonian Early Carboniferous Late Carboniferous Permian Triassic Jurassic Late Jurassic Cretaceous K/T extinction Eocene Miocene Last Ice Age Modern World Future World Future +100 Future +250

αΩ Beginning αΩ Hadean αΩ abiogenesis αΩ LUCA αΩ phylogenetic tree αΩ evolution of oxygenic photosynthesis αΩ geological time αΩ timeline of life αΩ fossilization αΩ Ediacara Biota ▫ site map

tags [Evolution] [geological timeline]