Timeline of glaciation

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Climate history over the past 500 million years, with the last three major ice ages indicated, Andean-Saharan (450 Ma), Karoo (300 Ma) and Late Cenozoic. A less severe cold period or ice age is shown during the Jurassic-Cretaceous (150 Ma). Phanerozoic Climate Change.png
Climate history over the past 500 million years, with the last three major ice ages indicated, Andean-Saharan (450 Ma), Karoo (300 Ma) and Late Cenozoic. A less severe cold period or ice age is shown during the Jurassic-Cretaceous (150 Ma).

There have been five or six major ice ages in the history of Earth over the past 3 billion years. The Late Cenozoic Ice Age began 34 million years ago, its latest phase being the Quaternary glaciation, in progress since 2.58 million years ago.

Contents

Within ice ages, there exist periods of more severe glacial conditions and more temperate conditions, referred to as glacial periods and interglacial periods, respectively. The Earth is currently in such an interglacial period of the Quaternary glaciation, with the Last Glacial Period of the Quaternary having ended approximately 11,700 years ago. The current interglacial is known as the Holocene epoch. [1] Based on climate proxies, paleoclimatologists study the different climate states originating from glaciation.

Known ice ages

GlaciationsinEarthExistancelicenced annotated.jpg

Name of ice ageYears BP (Ma)Geological periodEra
Pongola 2900–2780 [2] Mesoarchean
Huronian 2400–2100 Siderian
Rhyacian 		Paleoproterozoic
Sturtian
Marinoan
Gaskiers
Baykonur 		715–680
650–635
580
547		 Cryogenian

Ediacaran 		Neoproterozoic
Andean-Saharan
(incl. Hirnantian and
Late Ordovician glaciation)		450–420Late Ordovician
Silurian 		Paleozoic
Karoo 360–289 Carboniferous
Permian 		Paleozoic
Late Cenozoic Ice Age
(incl. Quaternary glaciation)		34–presentLate Paleogene
Neogene
Quaternary 		Cenozoic

Descriptions

The third ice age, and possibly most severe, is estimated to have occurred from 720 to 635  Ma (million years) ago, [3] in the Neoproterozoic Era, and it has been suggested that it produced a second [4] "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 [4] 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, [5] [6] though is gaining credence among researchers, as evidence in its favour has mounted. [7]

A minor series of glaciations occurred from 460 to 430 Ma, and there were extensive glaciations from 350 to 289 Ma.

The Late Cenozoic Ice Age has seen extensive ice sheets in Antarctica for the last 34 Ma. During the last 3 Ma, 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. [8]

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. [9] 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. [10] 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). [11]

Land-based evidence works acceptably well back as far as MIS 6, 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. [9]

Historical nomenclature in the Alps

Historical nomenclature in Great Britain and Ireland

Historical nomenclature in Northern Europe

Historical nomenclature in North America

Historical nomenclature in South America

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 200-300 thousand 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. [14]

Marine
isotope
stage 		Time ago
(ka)
[15] 		Regional namesGlobal
age /
epoch
Alpine regionGreat BritainN. EuropeE. EuropeN. AmericaS. America
MIS 103-642600–1800 Biber [16] Pre-Ludham [17]
Ludham [17]
Thurnian [17]
Bramerton [17]
Bavents [17]
Paston [17] 		Pre-Tiglian [18]
Tiglian A [18]
Tiglian B [18]
Tiglian C3 [18]
Tiglian C4 [18]
Tiglian C5 [18] 		Verkhodon [17]

Khapry [17] 		Pre-illinois K [17]

Pre-illinois J [17] 		Gelasian
MIS 63-231800–900 Danube [16] Beeston [17] Eburon [16]
Waal [16]
Menap [16]
Bavel [16] 		Tolucheevka [17]

Krinitsa [17] 		Pre-illinois I [17]
Pre-illinois H [17]
Pre-illinois G [17] 		Calabrian
MIS 22900–866 Günz Cromer [19] Cromer Pre-illinois F [17]
MIS 21866–814 Günz Cromer [19] Cromer Pre-illinois
MIS 20814–790 Günz Cromer [19] Cromer Pre-illinois E ?
MIS 19790–761 Günz [16] Cromer [19] Cromer [16] Pre-illinois Chibanian
MIS 18761-712 Günz [16] Cromer [19] Cromer [16] Pre-illinois E ?
MIS 17712-676 Günz [16] Cromer [19] Cromer [16] Pre-illinois
MIS 16676–621 Günz [16] Cromer [19] Cromer/Don [20] Don [21] Pre-illinois D [17]
MIS 15621–563 Günz [16] Cromer [19] Cromer [16] Muchkap [22] Pre-illinois
MIS 14563–533 Günz [16] Cromer [19] Cromer [16] Oka? [21] Pre-illinois C [17]
MIS 13533–478 Günz [16] Cromer [19] Cromer [16] Oka? [21] Pre-illinois
MIS 12478–424 Günz [16] Mindel? [23] Anglia [19] Elster [21] Cromer? [16] Oka [21] Pre-illinois B [17] Caracoles [13] Río Frío? [13]
MIS 11424–374 Günz? [16] Hoxne [17] Holstein [17] Cromer/Rhume? [16] Likhvin [24] Pre-illinois
MIS 10374–337 Mindel? [16] Wolston [17] Elster? [16] [21] Likhvin? [24] Pre-illinois A ?Río Llico [13] Colegual? [13]
MIS 9337–300 Mindel-Riss? [16] Wolston [17] Purfleet [25] Holstein? [16] Likhvin [24] Pre-illinois
MIS 8300–243 Riss [16] Wolston [17] Saale/Fuhne [16] AC Pre-illinois A ?
MIS 7243–191 Riss [16] Wolston [17] Aveley [25] Saale/Dömnitz [16] Belvedere [26] AC Pre-illinois
MIS 6191–130 Riss [16] Wolston [17] Saale/Drenthe,Warthe [16] Dnieper/Moscow [22] Illinois [27] Santa María [13] Casma? [13]
MIS 5e123 (peak) Riss-Würm [16] Ipswich [17] Eem Mikulino [22] Sangamonian Valdivia Late
Pleistocene

('Tarantian')
MIS 5d109 (peak) Würm [16] Devens/Early D. [28] Weichsel/Herning [29] Valdai [22] ACAC
MIS 5c96 (peak) Würm [16] Devens/Early D. [28] Weichsel/Brørup [29] Valdai [22] ACAC
MIS 5b87 (peak) Würm [16] Devens/Early D. [28] Weichsel/Rederstall [29] Valdai [22] ACAC
MIS 5a82 (peak) Würm [16] Devens/Early D. [28] Weichsel/Odderade [29] Valdai [22] ACAC
MIS 471–57 Würm [16] Devens/Middle D. [28] Weichsel/Middle W. [29] Valdai [22] Wisconsin Llanquihue
MIS 357–29 Würm [16] Devens/Middle D. [28] Weichsel/Middle W. [29] Valdai [22] Wisconsin Llanquihue
MIS 229–14 Würm/LGM Devens/Dimlington Weichsel/LGM Valdai [22] Wisconsin/Vashon Llanquihue/LGM
MIS 114–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

Sources

For sources to the tables, see the individual linked articles.

See also

Related Research Articles

<span class="mw-page-title-main">Pleistocene</span> First epoch of the Quaternary Period

The Pleistocene is the geological epoch that lasted from c. 2.58 million to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International Union of Geological Sciences, the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The name is a combination of Ancient Greek πλεῖστος (pleîstos), meaning "most", and καινός, meaning "new".

<span class="mw-page-title-main">Anglian stage</span> Period of the Pleistocene epoch

The Anglian Stage is the name used in the British Isles for a middle Pleistocene glaciation. It precedes the Hoxnian Stage and follows the Cromerian Stage in the British Isles. It correlates to Marine Isotope Stage 12, which started about 478,000 years ago and ended about 424,000 years ago.

The Cromerian Stage or Cromerian Complex, also called the Cromerian, is a stage in the Pleistocene glacial history of north-western Europe, mostly occurring more than half a million years ago. It is named after the East Anglian town of Cromer in Great Britain where interglacial deposits that accumulated during part of this stage were first discovered. The stratotype for this interglacial is the Cromer Forest Bed situated at the bottom of the coastal cliff near West Runton. The Cromerian stage preceded the Anglian and Elsterian glacials and show an absence of glacial deposits in western Europe, which led to the historical terms Cromerian interglacial and the Cromerian warm period. It is now known that the Cromerian consisted of multiple glacial and interglacial periods.

The Hoxnian Stage was a middle Pleistocene stage of the geological history of the British Isles. It was an interglacial which preceded the Wolstonian Stage and followed the Anglian Stage. It is equivalent to Marine Isotope Stage 11. Marine Isotope Stage 11 started 424,000 years ago and ended 374,000 years ago. The Hoxnian is divided into sub-stages Ho I to Ho IV. It is likely equivalent to the Holstein Interglacial in Central Europe.

The Wolstonian Stage is a middle Pleistocene stage of the geological history of Earth from approximately 374,000 until 130,000 years ago. It precedes the Last Interglacial and follows the Hoxnian Stage in the British Isles.

The Kansan glaciation or Kansan glacial was a glacial stage and part of an early conceptual climatic and chronological framework composed of four glacial and interglacial stages.

The Illinoian Stage is the name used by Quaternary geologists in North America to designate the Penultimate Glacial Period c.191,000 to c.130,000 years ago, during the late Middle Pleistocene (Chibanian), when sediments comprising the Illinoian Glacial Lobe were deposited. It precedes the Sangamonian Stage and follows the Pre-Illinoian Stage in North America. The Illinoian Stage is defined as the period of geologic time during which the glacial tills and outwash, which comprise the bulk of the Glasford Formation, accumulated to create the Illinoian Glacial Lobe. It occurs at about the same time as the penultimate glacial period.

The Yarmouthian stage and the Yarmouth Interglacial were part of a now obsolete geologic timescale of the early Quaternary of North America.

<span class="mw-page-title-main">Elster glaciation</span>

The Elster glaciation or, less commonly, the Elsterian glaciation, in the older and popular scientific literature also called the Elster Ice Age (Elster-Eiszeit), is the oldest known ice age that resulted in the large-scale glaciation of North Germany and other parts of Europe. It took place approximately 500,000–400,000 years ago. It succeeded a long period of rather warmer average temperatures, the Cromerian Complex. The Elster was followed by the Holstein interglacial, which was followed Saale glaciation. The glacial period is named after the White Elster, a right tributary of the Saale.

<span class="mw-page-title-main">Mindel glaciation</span>

The Mindel glaciation is the third youngest glacial stage in the Alps. Its name was coined by Albrecht Penck and Eduard Brückner, who named it after the Swabian river, the Mindel. The Mindel glacial occurred in the Middle Pleistocene; it was preceded by the Haslach-Mindel interglacial and succeeded by the Mindel-Riss interglacial.

The Beestonian Stage is an early Pleistocene stage in the geological history of the British Isles. It is named after Beeston Cliffs near West Runton in Norfolk where deposits from this stage are preserved.

The Pastonian interglacial, now called the Pastonian Stage, is the name for an early or middle Pleistocene stage of geological history in the British Isles. It precedes the Beestonian Stage and follows the Pre-Pastonian Stage. Unfortunately the precise age of this stage cannot yet be defined in terms of absolute dating or MIS stages. The Pre-Pastonian Stage is equivalent to the Tiglian C5-6 Stage of Europe and the Pre-Illinoian I glaciation of the early Pre-Illinoian Stage of North America.

The Pre-Pastonian Stage or Baventian Stage, is the name for an early Pleistocene stage of geological history in the British Isles. It precedes the Pastonian Stage and follows the Bramertonian Stage. This stage ended 1.806 Ma at the end of Marine Isotope Stage 65. It is not currently known when this stage started. The Pre-Pastonian Stage is equivalent to the Tiglian C4c Stage of Europe and the Pre-Illinoian J glaciation of the early Pre-Illinoian Stage of North America.

The Bramertonian Stage is the name for an early Pleistocene biostratigraphic stage of geological history the British Isles. It precedes the Pre-Pastonian Stage. It derives its name from Bramerton Pits in Norfolk, where the deposits can be found on the surface. The exact timing of the beginning and end of the Bramertonian Stage is currently unknown. It is only known that it is equivalent to the Tiglian C1-4b Stage of Europe and early Pre-Illinoian Stage of North America. It lies somewhere in time between Marine Oxygen Isotope stages 65 to 95 and somewhere between 1.816 and 2.427 Ma. The Bramertonian is correlated with the Antian stage identified from pollen assemblages in the Ludham borehole.

<span class="mw-page-title-main">Marine isotope stages</span> Alternating warm and cool periods in the Earths paleoclimate, deduced from oxygen isotope data

Marine isotope stages (MIS), marine oxygen-isotope stages, or oxygen isotope stages (OIS), are alternating warm and cool periods in the Earth's paleoclimate, deduced from oxygen isotope data derived from deep sea core samples. Working backwards from the present, which is MIS 1 in the scale, stages with even numbers have high levels of oxygen-18 and represent cold glacial periods, while the odd-numbered stages are lows in the oxygen-18 figures, representing warm interglacial intervals. The data are derived from pollen and foraminifera (plankton) remains in drilled marine sediment cores, sapropels, and other data that reflect historic climate; these are called proxies.

<span class="mw-page-title-main">Interglacial</span> Geological interval of warmer temperature that separates glacial periods within an ice age

An interglacial period is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene interglacial began at the end of the Pleistocene, about 11,700 years ago.

<span class="mw-page-title-main">Holstein interglacial</span>

The Holstein or Holsteinian interglacial, also called the Mindel-Riss interglacial (Mindel-Riß-Interglazial) in the Alpine region, is the third to last major interglacial in Europe before the Holocene, the present warm period. It followed directly after the Elster glaciation and came before the Saale glaciation, during the Middle Pleistocene. The more precise timing was historically controversial since Holstein was commonly correlated to two different marine isotope stages, MIS 11 and MIS 9. Recent scholarship has supported a MIS 11 date, spanning approximately 421-395,000 years ago.

The Pre-Illinoian Stage is used by Quaternary geologists for the early and middle Pleistocene glacial and interglacial periods of geologic time in North America from ~2.5–0.2 Ma.

The Sangamonian Stage is the term used in North America to designate the Last Interglacial and depending on definition, part of the early Last Glacial Period, corresponding to Marine Isotope Stage 5. While often historically considered equivalent in scope to MIS 5, it is now often used in a more narrow sense to refer to the Last Interglacial only. It preceded the Wisconsinan (Wisconsin) Stage and followed the Illinoian Stage in North America.

<span class="mw-page-title-main">Don Glaciation</span> Major glaciation of eastern Europe

The Don Glaciation, also known as the Donian Glaciation and the Donian Stage, was the major glaciation of the East European Plain, 0.5–0.8 million years ago, during the Cromerian Stage of the Middle Pleistocene. It is correlated to Marine Isotope Stage 16, approximately 650,000 years ago, which globally contained one of the largest glacial volumes of the Quaternary.

References

  1. ↑ 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. ISSN   0267-8179.
  2. ↑ Robert E. Kopp; Joseph L. Kirschvink; Isaac A. Hilburn & Cody Z. Nash (2005). "The Paleoproterozoic snowball Earth: A climate disaster triggered by the evolution of oxygenic photosynthesis". Proc. Natl. Acad. Sci. U.S.A. 102 (32): 11131–6. Bibcode:2005PNAS..10211131K. doi: 10.1073/pnas.0504878102 . PMC   1183582 . PMID   16061801.
  3. ↑ "Chart". International Commission on Stratigraphy. Archived from the original on 2017-01-13. Retrieved 2017-02-14.
  4. 1 2 Miracle Planet: Snowball Earth, (2005) documentary, Canadian Film Board, rebroadcast 25 April 2009 on the Science Channel (HD).
  5. ↑ van Andel, Tjeerd H. (1994). New Views on an Old Planet: A History of Global Change (2nd ed.). Cambridge UK: Cambridge University Press. ISBN   978-0-521-44755-3.
  6. ↑ Rieu, Ruben; et al. (2007). "Climatic cycles during a Neoproterozoic "snowball" glacial epoch". Geology. 35 (4): 299–302. Bibcode:2007Geo....35..299R. doi:10.1130/G23400A.1.
  7. ↑ "The Cambrian Period". ucmp.berkeley.edu. Retrieved 2024-02-26.
  8. ↑ Brovkin, V.; Calov, R.; Ganopolski, A.; Willeit, M. (April 2019). "Mid-Pleistocene transition in glacial cycles explained by declining CO2 and regolith removal | Science Advances". Science Advances. 5 (4): eaav7337. doi:10.1126/sciadv.aav7337. PMC   6447376 . PMID   30949580.
  9. 1 2 Davis, Owen K. "Non-Marine Records: Correlations with the Marine Sequence". Introduction to Quaternary Ecology. University of Arizona. Archived from the original on 2017-07-27.
  10. ↑ Gibbard, P.; van Kolfschoten, T. (2004). "Chapter 22: The Pleistocene and Holocene Epochs" (PDF). In Gradstein, F. M.; Ogg, James G.; Smith, A. Gilbert (eds.). A Geologic Time Scale 2004. Cambridge: Cambridge University Press. ISBN   978-0-521-78142-8.
  11. ↑ Kukla, George (August 2005). "Saalian supercycle, Mindel/Riss interglacial and Milankovitch's dating". Quaternary Science Reviews. 24 (14–15): 1573–83. Bibcode:2005QSRv...24.1573K. doi:10.1016/j.quascirev.2004.08.023.
  12. ↑ "Menapian Glacial Stage | geology".
  13. 1 2 3 4 5 6 7 8 9 Porter, S.C. (1981). "Pleistocene glaciation in the southern Lake District of Chile". Quaternary Research . 16 (3): 263–292. Bibcode:1981QuRes..16..263P. doi:10.1016/0033-5894(81)90013-2. S2CID   140544020.
  14. ↑ Böse; et al. (2012). "Quaternary Glaciations of Northern Europe". Quaternary Science Reviews (44): 17. CiteSeerX   10.1.1.734.1691 .
  15. ↑ Lisiecki, Lorraine E.; Raymo, Maureen E. (2005). "A Pliocene-Pleistocene stack of 57 globally distributed benthic δ18O records". Paleoceanography. 20 (1): n/a. Bibcode:2005PalOc..20.1003L. doi:10.1029/2004PA001071. hdl: 2027.42/149224 . S2CID   12788441.
  16. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 German Stratigraphic Commission: Stratigraphische Tabelle von Deutschland 2016
  17. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Subcommission on Quaternary Stratigraphy, Global chronostratigraphical correlation table for the last 2.7 million years, v. 2011
  18. 1 2 3 4 5 6 Kasse (1993), Periglacial environments and climate development during Early Pleistocene Tiglian stage (Beerse Glacial) in northern Belgium, Geologie en Mijnbouw 72, 107–123, Kluwer
  19. 1 2 3 4 5 6 7 8 9 10 11 Lee 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.
  20. ↑ "North West European Rivers 3: Don Glaciation (Donian Stage)". University of Cambridge: Quaternary Palaeoenvironments Group.
  21. 1 2 3 4 5 6 Böse; et al. (2012). "Quaternary Glaciations of Northern Europe". Quaternary Science Reviews. 44 (44): 1–25. Bibcode:2012QSRv...44....1B. CiteSeerX   10.1.1.734.1691 . doi:10.1016/j.quascirev.2012.04.017.
  22. 1 2 3 4 5 6 7 8 9 10 Velichko; et al. (2004). "Glaciations of the East European Plain – distribution and chronology". In Ehlers, J.; Gibbard, P.L. (eds.). Quaternary Glaciations – Extent and Chronology. Elsevier. pp. 337–354. ISBN   9780080540146.
  23. ↑ Stratigraphische Tabellen des Bayerischen Geologischen Landesamtes. Ad hoc AG Geologie der Staatlichen Geologischen Dienste (SGD) and the BGR
  24. 1 2 3 Velichko, A. A.; Wright, Herbert Edgar (2005). Cenozoic Climatic and Environmental Changes in Russia. Geological Society of America. p. 53. ISBN   9780813723822.
  25. 1 2 "Timescale of the Ice Age in Essex" (PDF). GeoEssex. Archived from the original (PDF) on 2 April 2019.
  26. ↑ Kolfschoten, Thijs van; Roebroeks, W.; Vandenberghe, J. (January 1993). "The middle and late Pleistocene and climate sequence at Maastricht-Belvedere - the type locality of the Belvedere interglacial". Mededelingen Rijks Geologische Dienst (47): 81–91.
  27. ↑ McKay, 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.
  28. 1 2 3 4 5 6 Delaney, Catherine (2003). "The Last Glacial Stage (the Devensian) in Northwest England" (PDF). North West Geography. 3 (2): 27–37. ISSN   1476-1580.
  29. 1 2 3 4 5 6 Lokrantz, Hanna; Sohlenius, Gustav (2006). Ice marginal fluctuations during the Weichselian glaciation in Fennoscandia, a literature review (Technical Report TR-06-36) (PDF). Stockholm: Svensk Kärnbränslehantering AB (Swedish Nuclear Fuel and Waste Management Co).

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