EarthStructure - Geologic Time Scale

Geologic Time Scale

Eon	Era	Period	Age at boundary

		Quaternary	2 Ma
	Cenozoic	Tertiary	66 Ma

		Cretaceous	144 Ma
	Mesozoic	Jurassic	208 Ma
		Triassic	250 Ma
Phanerozoic
		Permian	286 Ma
		Carboniferous (Pennsylvanian and Mississippian)	360 Ma (320 Ma and 360 Ma)
	Paleozoic	Devonian	408 Ma
		Silurian	438 Ma
		Ordovician	490 Ma
		Cambrian	545 Ma

	Neoproterozoic		1000 Ma
Proterozoic	Mesoproterozoic		1600 Ma
	Paleoproterozoic		2500 Ma

	Late		3000 Ma
Archean	Middle		3400 Ma
	Early		4000 Ma (~ age of oldest rock)

Modified from a 1983 compilation for the Decade of North American Geology (DNAG) project of the Geological Society of America. A new Geologic Time Scale is available as Acrobat PDF format; click here.

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