Geologic Time Scale

Scientists during the time of the Great Inventing created a scale named the Geologic Time Scale to determine the history of Earth. Based on findings, they created a scale that was separated into different divisions called eons, eras, periods & epochs. They also adopted the term "supereon" to account the timeline that contained the majority of eons in the Earth's history.

Scale

Supereon	Eon	Era	Period	Epoch	Span	Main events
	Phanerozoic	Cenozoic	Quaternary	Holocene	12 tya - Today	Human civilization
				Pleistocene	1 mya - 12 tya	Ice age
			Tertiary	Pliocene	65 - 1 mya	Human evolution
				Miocene
				Oligocene
				Eocene
				Paleocene
		Mesozoic	Cretaceous		144 - 65 mya	Cretaceous Mass Extinction
			Jurassic		200 - 144 mya	Dinosaurs enter Age of the Giants
			Triassic		250 - 200 mya	Dinosaurs first appear
		Paleozoic	Permian		300 - 250 mya	Permian Mass Extinction
			Pennsylvanian		360 - 300 mya	Life on land continues to bloom
			Devonian		380 - 360 mya	Life on land
			Silurian		417 - 360 mya	Life in ocean continues to evolve
			Ordovician		485 - 417 mya	Gondwana forms
			Cambrian		542 - 485 mya	Cambrian Explosion
Precambrian	Proterozoic	Neoproterozoic	Vendian		2.5 bya - 542 mya	Snowball Earth
			Cyrogenian
			Tonian			?
		Mesoproterozoic	Stenian			?
			Ectasian			?
			Calymmian			?
		Paleoproterozoic	Statherian			?
			Orosirian			?
			Rhyacian			?
			Siderian			?
	Archean	Neoarchean			3.8 - 2.5 bya	?
		Mesoarchean				?
		Paleoarchean				Stromatolites appear
		Eoarchean				First life
	Hadean				4.6 - 3.8 bya	Origin of the Earth
	Chaotian				14 - 4.6 bya	Big Bang & Formation of the Solar System

History of Earth

Main article: History of Earth

Chaotian Eon

Main article: Chaotian

The eon prior to the start of the Hadean & the Precambrian Supereon is the Chaotian. The Chaotian was recognized as the time before the formation of Earth & spans from the time of the Big Bang at the beginning of the universe 14 billion years before the present up to about 5 to 4.6 billion years ago when the Earth formed.

Precambrian Supereon

Main article: Precambrian

The Precambrian Supereon is all time before the Cambrian Explosion in the Cambrian Period of the Paleozoic Era of the Phanerozoic Eon. It depicts 90% of the entire history of Earth.

Hadean Eon

Main article: Hadean

As a newborn planet, Earth was a giant molten ball of fire with an atmosphere that had little or no oxygen. After about 100 million years after it's creation, the Moon was captured & put into an orbit over the Earth. The Earth then cooled to form a crust over the next 600 million years. 3.9 billion years ago, the Earth entered the Late Heavy Bombardment, when meteors attacked the Earth & supplyed water for the world's oceans. During the Bombardment that lasted 100 million years, the Moon distanced from Earth, slowing the planet's rotation & lowering tides.

Archean Eon

Main article: Archean

3.8 billion years ago, in the oceans, bacteria appeared as the first life. Over time, they began evolving into newer prokaryotic (unicellular) organisms, becoming cyanobacteria, which cemented with minerals from the rocks on the seabeds in shallow waters to become a structure called stromatolites. Cyanobacteria, using photosynthesis, created oxygen over the next 2 billion years.

Proterozoic Eon

Main article: Proterozoic

Stromatolites from the Archean continued to create oxygen for the atmosphere. At the end of the Mesoproterozoic Era, the Earth generated heat that made the mantle break the crust into plates that made islands collide & merge. 1 billion years ago, the plates formed the first supercontinent in Earth's history, Rodinia. Rodinia existed for about 350 million years before it broke apart. 558 million years ago, global cooling, caused by volcanic activity spawned from the breakup of Rodinia, starts Snowball Earth, a fifteen million year long ice age that was the longest & coldest in Earth's history. 543 million years ago, the Earth's volcanoes break the surface of the ice & warm the atmosphere.

Phanerozoic Eon

Main article: Phanerozoic

Paleozoic Era

Main article: Paleozoic

Cambrian

Main article: Cambrian

Ordovician

Main article: Ordovician

Silurian

Main article: Silurian

Devonian

Main article: Devonian

Pennsylvanian

Main article: Pennsylvanian

Permian

Main article: Permian

Mesozoic Era

Main article: Mesozoic

Triassic

Main article: Triassic

Jurassic

Main article: Jurassic

Cretaceous

Main article: Cretaceous

Cenozoic Era

Main article: Cenozoic

Tertiary

Main article: Tertiary

Quaternary

Main article: Quaternary

Pleistocene

Main article: Pleistocene

Holocene

Main article: Holocene

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