Timeline of glaciation

Encyclopedia : T : TI : TIM : Timeline of glaciation

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There have been four major periods of glaciation in the Earth's past. The first, and possibly most severe, may have occurred from 800 Ma to 600 Ma (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, a time of rapid diversification of multicelled life during the Cambrian era. However, this theory is recent and controversial.

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

Pleistocene glacial cycles

Originally, the periods were named after characteristic geological features, and these names vary from region to region. It is now perhaps more common (before the previous interglacial to the current (Holocene) one, the Eemian) to refer to periods by their Marine isotopic stage number. The marine record preserves all the past glaciations; the land-based evidence is less complete because successive glaciations may wipe out evidence of their predecessors. Hence the "names" system is incomplete: the Pastonian glaciation is MIS63, i.e., the 30th interglacial before present.

The last glacial and interglacial phases of the Pleistocene are named, from most recent to most distant, as follows. Dates shown are in thousand years BCE.

Backwards Glacial Index	Name Alpine	Name N. American	Name N. European	Name Great Britain	Inter/Glacial	Period (ka)	MIS	Epoch
				Flandrian	interglacial	present – 12	MIS1	Holocene
1st	Würm	Wisconsinan	Weichsel or Vistula	Devensian	glacial period	15 –   70	MIS2-4 & 5a-d	Pleistocene
	Riss-Würm	Sangamon	Eemian	Ipswichian	interglacial	110 – 130	MIS5e
2nd	Riss	Illinoian	Saale	Wolstonian or Gipping	glacial period	125 – 200	MIS6
	Mindel-Riss	Yarmouth	Holstein	Hoxnian	interglacial(s)	200 – 425	MIS7
3rd – 6th	Mindel	Kansan	Elster	Anglian	glacial period(s)	240 – 455
	Günz-Mindel	Aftonian		Cromerian	interglacial(s)	455 – 620
7th	Günz	Nebraskan	Menapian	Beestonian	glacial period	620 – 680

Other older periods of the Pleistocene

Name	Inter/Glacial	Period (ka)	MIS	Epoch
Waalian	interglacial	470 – 540		Pleistocene
Donau II	glacial period	540 – 550
Tiglian	interglacial	550 – 585
Donau I	glacial period	585 – 600
Pastonian interglacial	interglacial	600 – 800	MIS63
Pre-Pastonian glaciation	glacial period	800 – 1300
Bramertonian Interglacial	interglacial	1300 – 1550

The Brunhes-Matuyama reversal occurred 780,000 years ago, approximately coincident with MIS19, the "Cromerian Complex" interglacial I, and can be used to date sediment cores.

Major glacial periods

Name	Period (Ma)	Period	Era
	30 - present	Neogene	Cenozoic
Karoo	360 - 260	Carboniferous and Permian	Paleozoic
Andean-Saharan	450 - 420	Ordovician and Silurian	Paleozoic
Cryogenian (or Sturtian-Varangian)	800 - 635	Cryogenian	Neoproterozoic
Huronian	2100 - 2400	Siderian and Rhyacian	Paleoproterozoic

References

• http://www-qpg.geog.cam.ac.uk/people/gibbard/GTS2004Quat.pdf (fig 22.1)

See also

• Geologic timescale
• Ice age
• Varanger glaciation

 

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