Tertiary facts for kids

The Tertiary was an official geological period, but it is no longer used. It included the first part of the Cainozoic. This is now divided into the Palaeogene and the Neogene.

The previous use of the term "Tertiary" explains why the last period of the Cainozoic is called the Quarternary. There was a big debate about that. These decisions are made by the International Union of Geological Sciences (IUGS). This organisation runs an International Commission on Stratigraphy, which decides how we should name geological strata and stages.

In 19th and 20th century scientific literature, Tertiary is used where geologists now use Palaeogene and Neogene.

Geologic history

Precambrian (4.567 gya – 541 mya)
In the left column are Eons, bold are Eras, not bold are Periods. gya = billion years ago, mya = million years ago
Hadean (4.567 gya – 4 gya)	Chaotian Zirconian
Archaean (4 gya – 2.5 gya)	Eoarchaean (4 gya – 3.6 gya) Palaeoarchaean (3.6 gya – 3.2 gya) Mesoarchaean (3.2 gya – 2.8 gya) Neoarchaean (2.8 gya – 2.5 gya)
Proterozoic (2.5 gya – 541 mya)	Palaeoproterozoic (2.5 gya – 1.6 gya) Siderian (2.5 gya – 2.3 gya) Rhyacian (2.3 gya – 2.05 gya) Orosirian (2.05 gya – 1.8 gya) Statherian (1.8 gya – 1.6 gya) Mesoproterozoic (1.6 gya – 1 gya) Calymmian (1.6 gya – 1.4 gya) Ectasian (1.4 gya – 1.2 gya) Stenian (1.2 gya – 1 gya) Neoproterozoic (1 gya - 541 mya) Tonian (1 gya – 720 mya) Cryogenian (720 mya – 635 mya) Ediacaran (635 mya – 541 mya)

Phanerozoic (541 mya – today)
In the left column are Eras, bold are Periods, not bold or italics are Epochs, Italics are stages. kya = thousand years ago, mya = million years ago
Palaeozoic (541 mya – 252.17 mya)	Cambrian (541 mya – 485.4 mya) Ordovician (485.4 mya – 443.4 mya) Silurian (443.4 mya – 419.2 mya) Devonian (419.2 mya – 358.9 mya) Carboniferous (358.9 mya – 298.9 mya) Mississippian (358.9 mya – 323.2 mya) Pennsylvanian (323.2 mya – 298.9 mya) Permian (298.9 mya – 252.17 mya)
Mesozoic (252.17 mya – 66.0 mya)	Triassic (252.17 mya – 201.3 mya) Lower Triassic (252.17 mya – 247.2 mya) Middle Triassic (247.2 mya – 237 mya) Upper Triassic (237 mya – 201.3 mya) Jurassic (201.3 mya – 145 mya) Lower Jurassic (201.3 mya – 174.1 mya) Middle Jurassic (174.1 mya – 163.5 mya) Upper Jurassic (163.5 mya – 145 mya) Kimmeridgian (157.3–152.1 mya) Cretaceous (145 mya – 66.0 mya) Lower Cretaceous (145 mya – 100.5 mya) Upper Cretaceous (100.5 mya – 66.0 mya)
Cainozoic (66.0 mya – today) Tertiary (66.0 mya – 1.806 mya)	Palaeogene (66.0 mya – 23.03 mya) Palaeocene (66.0 mya – 56 mya) Eocene (56 mya - 33.9 mya) Oligocene (33.9 mya – 23.03 mya) Neogene (23.03 mya – 2.588 mya) Miocene (23.03 mya – 5.333 mya) Pliocene (5.333 mya – 2.588 mya) Quaternary (2.588 mya – today) Pleistocene (2.588 mya – 11.7 kya) Holocene (11.7 kya - today)