Timeline of glaciation

The earth has been free of permanent ice sheets for most of its history, and there have been nine glacial periods over the past 3 billion years. The earth is now in the Late Cenozoic Ice Age, which began around 33.9 million years ago, when ice began to build up in the Antarctic. Its latest phase is the Quaternary glaciation, which started around 2.58 million years ago and is still ongoing.

Within ice ages, there exist periods of more severe glacial conditions and more temperate conditions, referred to as glacial periods and interglacial periods, respectively. Earth is currently in such an interglacial period of the Quaternary glaciation, with the Last Glacial Period of the Quaternary having ended around 11,700 years ago. The current interglacial is known as the Holocene epoch.Walker, M., Johnsen, S., Rasmussen, S. O., Popp, T., Steffensen, J.-P., Gibbard, P., Hoek, W., Lowe, J., Andrews, J., Bjo¨ rck, S., Cwynar, L. C., Hughen, K., Kershaw, P., Kromer, B., Litt, T., Lowe, D. J., Nakagawa, T., Newnham, R., and Schwander, J. 2009. Formal definition and dating of the GSSP (Global Stratotype Section and Point) for the base of the Holocene using the Greenland NGRIP ice core, and selected auxiliary records. J. Quaternary Sci., Vol. 24 pp. 3–17. . Based on climate proxies, paleoclimatologists study the different climate states originating from glaciation.

Known ice ages

Name of ice age Years ago Period Era Pongola 2.985-2.837 Bya Mesoarchean Huronian 2.4–2.1 Bya SiderianRhyacian Paleoproterozoic Sturtian 717–660 Mya Cryogenian Neoproterozoic Marinoan 639-635 Mya Gaskiers 579.88–579.63 Mya Ediacaran Baykonurian 547–540 Mya Hirnantian 460–420 Mya OrdovicianSilurian Paleozoic Late Paleozoic icehouse 360–255 Mya CarboniferousPermian Late Cenozoic Ice Age 33.9 Mya–Present PaleogeneNeogeneQuaternary Cenozoic

Descriptions

The third ice age, and possibly most severe, is estimated to have occurred from around 717 to 660 million years ago, during the Cryogenian Period, and it has been suggested that it produced a secondMiracle Planet: Snowball Earth, (2005) documentary, Canadian Film Board, rebroadcast 25 April 2009 on the Science Channel (HD). "Snowball Earth", i.e. a period during which Earth was completely covered in ice. It has also been suggested that the end of that second cold period was responsible for the subsequent Cambrian explosion, a time of rapid diversification of multi-cellular life during the Cambrian Period. The hypothesis is still controversial, though is gaining credence among researchers, as evidence in its favour has mounted.

The Hirnantian glaciation lasted from around 460 to 420 million years ago, and then the Late Paleozoic icehouse from around 360 to 255 million years ago.

The Late Cenozoic Ice Age has seen extensive ice sheets in Antarctica for the last 33.9 million years. During the last 3 million years, ice sheets have also developed on the northern hemisphere. That phase is known as the Quaternary glaciation, and was marked by more or less extensive glaciation. They first appeared with a dominant frequency of 41,000 years, but after the Mid-Pleistocene Transition that changed to high-amplitude cycles, with an average period of 100,000 years.

Nomenclature of Quaternary glacial cycles Whereas the first 30 million years of the Late Cenozoic Ice Age mostly involved Antarctica, the Quaternary has seen numerous ice sheets extending over parts of Europe and North America that are currently populated and easily accessible. Early geologists therefore named apparent sequences of glacial and interglacial periods of the Quaternary Ice Age after characteristic geological features, and these names varied from region to region. 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. Ice cores from continental ice accumulations also provide a complete record, but do not go as far back in time as marine data. Pollen data from lakes and bogs as well as loess profiles provided important land-based correlation data. The names system has mostly been phased out by professionals. It is now more common for researchers to refer to the periods by their marine isotopic stage number. For example, there are five Pleistocene glacial/interglacial cycles recorded in marine sediments during the last half million years, but only three classic glacials were originally recognized on land during that period (Mindel, Riss, and Würm).

Land-based evidence works acceptably well back as far as MIS 6 (see Marine isotope stages, Stages), but it has been difficult to coordinate stages using just land-based evidence before that. Hence, the "names" system is incomplete and the land-based identifications of ice ages previous to that are somewhat conjectural. Nonetheless, land based data is essentially useful in discussing landforms, and correlating the known marine isotopic stage with them.

Historical nomenclature in the Alps Biber (2.6–1.8 Mya, Gelasian) Biber-Danube interglacial (not in use) Danube (1.8–1 Mya, Calabrian) Danube-Gunz interglacial (not in use) Günz (1–0.4 Mya, MIS 21 – MIS 11 ?) Günz-Haslach interglacial (not in use) Haslach (seldom used) Haslach-Mindel interglacial (not in use) Mindel (MIS 12?, MIS 10) Mindel-Riss interglacial (MIS 9) Riss (MIS 8-6) Riss-Würm interglacial (MIS 5e) Würm (MIS 5d-2)

Historical nomenclature in Great Britain and Ireland Bramertonian Stage Baventian Stage/Pre-Pastonian Pastonian Stage Beestonian stage Cromerian Stage (MIS 21-13 ?) Anglian Stage (MIS 12, perhaps also MIS 10 ?) Hoxnian Stage (MIS 11, perhaps also MIS 9 ?) Wolstonian Stage (MIS 8–6, perhaps also MIS 10–9 ?) Ipswichian interglacial (MIS 5e) Devensian glaciation (MIS 5d-2) Flandrian interglacial (MIS 1)

Historical nomenclature in Northern Europe Pre-Tiglian Tiglian interglacial Eburonian Waalian interglacial Menapian glacial stage Bavelian Cromerian complex (MIS 21-13 ?) Elster glaciation (MIS 12) Holstein interglacial (MIS 11) Saale glaciation (MIS 10-6) Eem interglacial (MIS 5e) Weichsel glaciation (MIS 5d-2)

Historical nomenclature in North America Nebraskan glaciation (replaced by Pre-Illinoian in modern scientific literature) Aftonian interglacial (replaced by Pre-Illinoian in modern scientific literature) Kansan glaciation (replaced by Pre-Illinoian in modern scientific literature) Yarmouthian (stage) (replaced by Pre-Illinoian in modern scientific literature) Illinoian stage (MIS 6) Sangamonian (MIS 5e, sometimes also 5d-5a) Wisconsin glaciation (MIS 4-2, sometimes also 5d-5a)

Historical nomenclature in South America Caracoles (Río Frío) glaciation Río Llico (Colegual) glaciation Santa María (Casma) glaciation Valdivia interglacial (MIS 5e) Llanquihue glaciation (at least MIS 4-2)

Uncertain correlations It has proved difficult to correlate the traditional regional names with the global marine and ice core sequences. The indexes of MIS often identify several distinct glaciations that overlap in time with a single traditional regional glaciation. Some modern authors use the traditional regional glacial names to identify such a sequence of glaciations, whereas others replace the word "glaciation" with "complex" to refer to a continuous period of time that also includes warmer stages. As shown in the table below, it is only during the last 200,000-300,000 years that the time resolution of the traditional nomenclature allow for clear correspondence with MIS indexes. In particular there has been a lot of controversy regarding the glaciations MIS 10 and MIS 12, and their correspondence to the Elster and Mindel glaciations of Europe.

MarineisotopestageTime ago(ka)Regional namesGlobalage /epoch Alpine region Great Britain N. Europe E. Europe N. America S. America MIS 103-64 2600–1800 Biber Pre-LudhamLudhamThurnianBramertonBaventsPaston Pre-TiglianTiglian ATiglian BTiglian C3Tiglian C4Tiglian C5Kasse (1993), Periglacial environments and climate development during Early Pleistocene Tiglian stage (Beerse Glacial) in northern Belgium, Geologie en Mijnbouw 72, 107–123, Kluwer VerkhodonKhapry Pre-illinois KPre-illinois J Gelasian MIS 63-23 1800–900 Danube BeestonSubcommission on Quaternary Stratigraphy, Global chronostratigraphical correlation table for the last 2.7 million years, v. 2011 EburonWaalMenapBavel TolucheevkaKrinitsa Pre-illinois IPre-illinois HPre-illinois G Calabrian MIS 22 900–866 Günz CromerLee et al. (2011), The Glacial History of the British Isles during the early and Middle Pleistocene: Implications for the long-term development of the British Ice Sheet, Quaternary Glaciations-Extent and Chronology, pages 59-74, Elsevier. Cromer Pre-illinois F MIS 21 866–814 Günz Cromer Cromer Pre-illinois MIS 20 814–790 Günz Cromer Cromer Pre-illinois E ? MIS 19 790–761 GünzGerman Stratigraphic Commission: Stratigraphische Tabelle von Deutschland 2016 Cromer Cromer Pre-illinois Chibanian MIS 18 761-712 Günz Cromer Cromer Pre-illinois E ? MIS 17 712-676 Günz Cromer Cromer Pre-illinois MIS 16 676–621 Günz Cromer Cromer/Don Don Pre-illinois D MIS 15 621–563 Günz Cromer Cromer Muchkap Pre-illinois MIS 14 563–533 Günz Cromer Cromer Oka? Pre-illinois C MIS 13 533–478 Günz Cromer Cromer Oka? Pre-illinois MIS 12 478–424 Günz Mindel?Stratigraphische Tabellen des Bayerischen Geologischen Landesamtes. Ad hoc AG Geologie der Staatlichen Geologischen Dienste (SGD) and the BGR Anglia Elster Cromer? Oka Pre-illinois B Caracoles Río Frío? MIS 11 424–374 Günz? Hoxne Holstein Cromer/Rhume? Likhvin Pre-illinois MIS 10 374–337 Mindel? Wolston Elster? Likhvin? Pre-illinois A ? Río Llico Colegual? MIS 9 337–300 Mindel-Riss? Wolston Purfleet Holstein? Likhvin Pre-illinois MIS 8 300–243 Riss Wolston Saale/Fuhne AC Pre-illinois A ? MIS 7 243–191 Riss Wolston Aveley Saale/Dömnitz Belvedere AC Pre-illinois MIS 6 191–130 Riss Wolston Saale/Drenthe, Warthe Dnieper/Moscow IllinoisMcKay, E.D., 2007, Six Rivers, Five Glaciers, and an Outburst Flood: the Considerable Legacy of the Illinois River. Proceedings of the 2007 Governor's Conference on the Management of the Illinois River System: Our continuing Commitment, 11th Biennial Conference, Oct. 2-4, 2007, 11 p. Santa María Casma? MIS 5e 123 (peak) Riss-Würm Ipswich Eem Mikulino Sangamonian Valdivia LatePleistocene('Tarantian') MIS 5d 109 (peak) Würm Devens/Early D. Weichsel/Herning Valdai AC AC MIS 5c 96 (peak) Würm Devens/Early D. Weichsel/Brørup Valdai AC AC MIS 5b 87 (peak) Würm Devens/Early D. Weichsel/Rederstall Valdai AC AC MIS 5a 82 (peak) Würm Devens/Early D. Weichsel/Odderade Valdai AC AC MIS 4 71–57 Würm Devens/Middle D. Weichsel/Middle W. Valdai Wisconsin Llanquihue MIS 3 57–29 Würm Devens/Middle D. Weichsel/Middle W. Valdai Wisconsin Llanquihue MIS 2 29–14 Würm/LGM Devens/Dimlington Weichsel/LGM Valdai Wisconsin/Vashon Llanquihue/LGM MIS 1 14–present (Holocene) Flandria Flandria (Holocene) (Holocene) (Holocene) Holocene

Table explanation Extensive interglacial (similar to Holocene) Moderate interglacial Intermediate climate Moderate glaciation Extensive glaciation (similar to LGM) AC = Ambiguous correlation

Timeline of glaciation

Bron en licentie