There have been four major periods of glaciation in the Earth's past. The first, and possibly most severe, may have occurred from 800 to 600 million years ago (the late Proterozoic Age) and it has been suggested that it produced a Snowball Earth in which the earth iced over completely. It has been suggested also that the end of this cold period was responsible for the subsequent Cambrian Explosion — this theory is recent and controversial.

A minor series of glaciations occurred from 460 to 430 million years ago. There were extensive glaciations from 350 million years before present to 250 million. The present Pleistocene ice age has seen more or less extensive glaciation on 40,000 and 100,000 year cycles. The last glacial period ended about 10,000 years ago.

Name	Inter/Glacial	Period	Geologic era
Wisconsinan / Weichsel or Vistula	glacial period,	15 –   70	Quaternary
Sangamon / Eemian	interglacial,	70 – 130
Illinoian / Saale	glacial,	130 – 180
Yarmouth / Holstein	interglacial,	180 – 230
Kansan / Elster	glacial,	230 – 300
Aftonian / Cromer	interglacial,	300 – 330
Nebraskan / Gunz	glacial,	330 – 470
— / Waalian	interglacial,	470 – 540
— / Donau II	glacial,	540 – 550
— / Tiglian	interglacial,	550 – 585
— / Donau I	glacial,	585 – 600
	glacial	250-350 Myr	Devonian, Carboniferous, Permian
	glacial	430-460 Myr	Ordovician
Sturtian-Varangian (or cryogene)	glacial	650-900 Myr	late Proterozoic

See also

• Geologic timescale