Geologic Time Scale January 25, 2010Posted by tanzaniageologists in Uncategorized.
This geologic time scale shows all the defined units of period rank, along with the eras and eons that comprise them. The periods of the Phanerozoic Eon are further subdivided into epochs; see those in the Phanerozoic Eon geologic time scale. Epochs are further subdivided into ages; see those in the Paleozoic Era, Mesozoic Era and Cenozoic Era geologic time scales.
The Proterozoic and Archean eons, along with the informal Hadean eon before 4000 million years ago, are together called Precambrian time.
The dates shown on this geologic time scale were specified by the International Commission on Stratigraphy in 2009. The colors were specified by the Committee for the Geologic Map of the World in 2009.