Pre-Illinoian Stage


Pre-Illinoian Stage

The Pre-Illinoian Stage is the name currently used for early and middle Pleistocene glacial and interglacial deposits within North America. As the oldest stage in the North American nomenclature, it precedes the Illinoian Stage.Hallberg, G.R., 1986, "Pre-Wisconsin glacial stratigraphy of the Central Plains region in Iowa, Nebraska, Kansas, and Missouri", Quaternary Science Reviews. vol. 5, pp. 11-15.] Richmond, G.M. and D.S. Fullerton, 1986, "Summation of Quaternary glaciations in the United States of America", Quaternary Science Reviews. vol. 5, pp. 183-196.] During the Pre-Illinoian Stage, 11 distinct glacial period have been recognized. In the British Isles, the Pre-Illinoian Stage is equivalent to the Bramertonian, Pre-Pastonian, Pastonian, Beestonian, Cromerian, Anglian, Hoxnian, and lowermost Wolstonian stages combined.Gibbard, P.L., S. Boreham, K.M. Cohen and A. Moscariello, 2007, [http://www.quaternary.stratigraphy.org.uk/correlation/POSTERSTRAT_v2007b_small.jpg"Global chronostratigraphical correlation table for the last 2.7 million years v. 2007b"] , jpg version 844 KB. Subcommission on Quaternary Stratigraphy, Department of Geography, University of Cambridge, Cambridge, England] The end of Marine Isotope Stage 9 is the end of the Pre-Illinoian Stage. Thus, the Pre-illinoian Stage ranges from the beginning of the Pleistocene until 300,000 years ago.Lisiecki, L.E., 2005, [http://www.lorraine-lisiecki.com/LR04_MISboundaries.txt "Ages of MIS boundaries."] [http://www.lorraine-lisiecki.com/stack.html LR04 Benthic Stack] Boston University, Boston, MA] Lisiecki, L.E., and M.E. Raymo, 2005, "A Pliocene-Pleistocene stack of 57 globally distributed benthic d18O records." Paleoceanography. vol. 20, PA1003, doi:10.1029/2004PA001071]

The Pleistocene prior to the Illinoian Stage had previously been subdivided into the Nebraskian (glacial), Aftonian (interglacial), Kansan (glacial), and Yarmouth (interglacial) stages (periods).Flint, R.F., 1957, "Glacial Geology and the Pleistocene Epoch." John Wiley & Sons, New York. 553 p. New York] However, detailed studies of these stages revealed that the assumptions and criteria, on which they were defined, proved to be wrong to the point that these stages became meaningless in terms of the actual glacial - interglacial record.Dort, W., Jr., 1966, "Nebraskan and Kansan Stades: Complexity and Importance." Science. vol. 154, no. 3750, pp. 771-772. DOI: 10.1126/science.154.3750.771] Boellstorff, J., 1978a, "Chronology of some Late Cenozoic deposits from the central United States and the Ice Ages. " Transactions of the Nebraska Academy of Science. vol 6, pp. 35–49] Boellstorff, J., 1978b, North American Pleistocene stages reconsidered in the light of probable Pliocene-Pleistocene continental glaciation." Science. vol. 202, pp. 305–307.] For example, instead of 2 glaciations having occurred prior to the Illinoian Stage, it was found that 11 distinct glaciations had occurred. In addition, what was presumed to be a single volcanic ash bed, which was used to correlate and differentiate between Kansan and Nebraskan glacial deposits, was found to actually be three volcanic ash beds of greatly differing ages. Similarly, paleosols used in the definition of the stages were found to have been greatly miscorrelated and consist of paleosols of greatly differing ages. Because of these and other major problems, the concepts, on which the Nebraskian, Aftonian, Kansan, and Yarmouth stages are defined, were discredited and these stages were discarded as unusable by North American geologists. As a result, these stages were merged into the Pre-Illinoian Stage.Roy, M., P.U. Clark, R.W. Barendregt, J.R., Glasmann, and R.J. Enkin, 2004, [http://geo.oregonstate.edu/people/faculty/publications/clarkp/Royetal-GSAB-2004.pdf "Glacial stratigraphy and paleomagnetism of late Cenozoic deposits of the north-central United States"] , PDF version, 1.2 MB. Geological Society of America Bulletin. vol. 116, no. 1-2; pp. 30-41; DOI: 10.1130/B25325.1]

References

External Links

*Aber, J.S., 2006, [http://academic.emporia.edu/aberjame/ice/lec17/lec17.htm "Regional Glaciation of Kansas and Nebraska"] , Emporia State University, Emporia, Kansas.
*anonymous, 1997, [http://www.emporia.edu/earthsci/gage/pre-wisc/gmap0.htm "Glacial Map of North-Central United States"] , Work Group on Geospatial Analysis of Glaciated Environments (GAGE), INQUA Commission on Glaciation, Emporia State University, Emporia, Kansas.
*anonymous, 2000, [http://www.emporia.edu/earthsci/gage/pre-wisc/pre-wisc.htm "Pre-Wisconsin Glaciation of Central North America"] , Work Group on Geospatial Analysis of Glaciated Environments (GAGE), INQUA Commission on Glaciation, Emporia State University, Emporia, Kansas.
*anonymous, 2007, [http://www.quaternary.stratigraphy.org.uk/correlation/chart.html "Global correlation tables for the Quaternary"] , Subcommission on Quaternary Stratigraphy, Department of Geography, University of Cambridge, Cambridge, England
*Hallberg, G.R., ed., 1980a, [http://gsbdata.igsb.uiowa.edu/gsbpubs/pdf/TIS-10.pdf "Pleistocene stratigraphy in east-central Iowa"] , PDF version 15.6 MB. Technical information Series. no. 10. Iowa Geological Survey Bureau, Ames, IA.
*Hallberg, G. R., ed., 1980b, [http://gsbdata.igsb.uiowa.edu/gsbpubs/pdf/TIS-11.pdf "Illinoian and Pre-Illinoian stratigraphy of southeast Iowa and adjacent Illinois"] , PDF version 19.3 MB. Technical information Series. no. 11. Iowa Geological Survey Bureau, Ames, IA.
*Hallberg, G. R., T. E. Fenton, T. J. Kemmis, and G. A. 
Miller, 1980, [http://www.igsb.uiowa.edu/gsbpubs/pdf/GB-03.pdf "Yarmouth Revisited: Midwest Friends of 
the Pleistocene 27th Field Conference."] , PDF version 4.6 MB. Guidebook no. 3. 
Iowa Geological Survey Bureau, Ames, IA.

Further reading

*Ehlers, J., and P.L. Gibbard, 2004a, "Quaternary Glaciations: Extent and Chronology 2: Part II North America", Elsevier, Amsterdam. ISBN 0-444-51462-7
*Gillespie, A.R., S.C. Porter, and B.F. Atwater, 2004, "The Quaternary Period in the United States. " Developments in Quaternary Science no. 1. Elsevier, Amsterdam. ISBN 978-0-444-51471-4
*Mangerud, J., J. Ehlers, and P. Gibbard, 2004, "Quaternary Glaciations: Extent and Chronology 1: Part I Europe", Elsevier, Amsterdam. ISBN 0-444-51462-7
*Sibrava, V., Bowen, D.Q, and Richmond, G.M., eds., 1986, "Quaternary Glaciations in the Northern Hemisphere, Quaternary Science Reviews", vol. 5, pp. 1-514.

ee also

*Ice age
*Glacial period
*Last glacial period
*Timeline of glaciation


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