How is time divided?

Answer 1

In geological time, 4.5 billion years is called "deep time." Anything less than that is considered quick in a geological scale.

Time is divided first into eons. Eons are divided into eras, and eras are divided into Systems, also called Periods. Periods are then divided into Series (Epochs) and then Stages (Ages) and lastly Chronozones. The following are all of the eons, eras, and periods in Earth's history. You can learn more about geological time by visiting the related link.

Hadean - 4.5 to 3.8 billion years ago (bya)

(Not divided into eras)

Archean - 3.8 to 2.5 byaEoarchean 3.8 - 3.5 byaPaleoarchean 3.5 - 3.1 byaMesoarchean 3.1 - 2.7 byaNeoarchean 2.7 - 2.5 byaNone of the above eras are divided into periods. Proterozoic - 2.5 to 0.54 byaPaleoproterozoic 2.5 - 1.6 bya

Siderian 2.5 - 2.3 bya

Rhyacian 2.3 - 2.05 bya

Orosirian 2.05 - 1.8 bya

Statherian 1.8 - 1.6 bya

Mesoproterozoic 1.5 - 1 bya

Calymmian 1.6 - 1.4 bya

Ectasian 1.4 - 1.2 bya

Stenian 1.2 - 1 bya

Neoproterozoic

Tonian 1 bya - 850 million years ago (mya)

Cryogenian 850 - 625 mya

Ediacaran 625 - 550 mya

Phanerozoic - 540 - 0 million years ago (mya)Paleozoic

Cambrian 542 - 488 mya

Ordovician 488 - 443 mya

Silurian 443 - 416 mya

Devonian 416 - 359 mya

Carboniferous 359 - 299 mya

Permian 299 - 251 mya

Mesozoic

Triassic 251 - 200 mya

Jurassic 200 - 146 mya

Cretaceous 146 - 66 mya

Cenozoic

Paleogene 66 - 23 mya

Neogene 23 - 2.6 mya

Quaternary 2.6 mya - Present