Earth Geology Geologic Time Scale

Explore this time scale by clicking on a time period name for more information about the period. Click on the "What's Happening" column for a brief discussion of the local and regional geologic history of that time period. For example, start with the Hadean Eon, read about Earth's Birth, then follow the pointing hands to move through time... 

Geologic Time Scale
Time Division Name			Time Span (mya = million years ago)	What's Happening
Precambrian	Hadean Eon		4,600 to 3,800 mya	Earth's Birth
	Archaean Eon		3,800 to 2,500 mya	Earliest life
	Proterozoic Eon		2,500 to 544 mya	St. Francis Mtns.
Paleozoic Era	Cambrian Period		544 to 505 mya	Marine deposition
	Ordovician Period		505 to 440 mya	Marine deposition
	Silurian Period		440 to 410 mya	Erosion
	Devonian Period		410 to 360 mya	Erosion
	Mississippian Period		360 to 325 mya	Marine deposition
	Pennsylvanian Period		325 to 286 mya	Deposition & erosion
	Permian Period		286 to 245 mya	Uplift and erosion
Mesozoic Era	Triassic Period		245 to 208 mya	Erosion
	Jurassic Period		208 to 146 mya	Erosion
	Cretaceous Period		146 to 65 mya	Erosion
Cenozoic Era	Tertiary Period	Paleocene Epoch	65 to 57.8 mya	Erosion
		Eocene Epoch	.57.8 to 36.6 mya
		Oligocene Epoch	36.6 to 23.7 mya	Age of Mammals
		Miocene Epoch	23.7 to 5.3 mya	Ice Ages
		Pliocene Epoch	5.3 to 1.8 mya
	Quaternary Period	Pleistocene Epoch	1.8 to 0.01 mya	Ice ages
		Holocene Epoch	0.01 mya to Now	Age of Man

The relative time scale gives a better representation of the true scale of time. Check it out for yourself!