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Aftonian
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 (million years ago). North America As the oldest stage in the North American regional subdivision of the Quaternary, the Pre-Illinoian precedes the Illinoian Stage. Researchers have identified 11 distinct glacial stages during the Pre-Illinoian Stage. The Pleistocene prior to the Illinoian stage had previously been subdivided into the Nebraskan, Aftonian, Kansan, and Yarmouthian stages (ages). However, detailed studies of these stages revealed that the assumptions and criteria on which they were defined proved to be wrong to such a point that these stages became meaningless in terms of the actual glacial–interglacial record. For example, instead of two glaciations having occurred prior to the Illinoian Stage, researchers found that 11 distinct glaciations had occurred. In addition, what was pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kansan Glaciation
The Kansan glaciation or Kansan glacial (see Pre-Illinoian) was a glacial stage and part of an early conceptual climatic and chronological framework composed of four glacial and interglacial stages. History Kansan glaciation was used by early geomorphologists and Quaternary geologists to subdivide glacial and nonglacial deposits within north-central United States from youngest to oldest and are as follows: *Wisconsin (glacial) *Sangamonian (interglacial) *Illinoian (glacial) * Yarmouthian (interglacial) *Kansan (glacial) * Aftonian (interglacial) * Nebraskan (glacial) As developed between 1894 and 1909, the Kansan Stage was based on a model that assumed that the Pleistocene deposits contained only two glacial tills and one volcanic ash bed within Nebraska and Kansas. Of these two proposed glacial tills, the Kansan till, which defined the Kansan Stage, was the upper of the two glacial tills and the Nebraskan till, which defined the Nebraskan Stage, was the lower of the two glacial t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yarmouthian (stage)
The Yarmouthian stage and the Yarmouth Interglacial were part of a now obsolete geologic timescale of the early Quaternary of North America. Development This climatic and chronological framework was composed of four glacial and interglacial stages. It was developed between 1894 and 1909 by geomorphologists and Quaternary geologists to subdivide glacial and nonglacial deposits within the United States of America. From youngest to oldest, they were the Wisconsinian Stage (glacial), Sangamonian (interglacial), Illinoian (glacial), Yarmouthian (interglacial), Kansan (glacial), Aftonian (interglacial), and Nebraskan (glacial) stages. The Yarmouthian (Yarmouth) Interglacial was defined first on the basis of "interglacial" sediments encountered in wells dug in southeasterm Iowa. Later the Yarmouth (Yarmouthian) stage in Illinois was defined on the basis of the Yarmouth Paleosol (Soil) developed in the surface of what were thought at that time to be "Kansan" glacial tills and buried b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 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 grc, label=none, πλεῖστος, pleīstos, most and grc, label=none, καινός, kainós (latinized as ), 'new'. At the end of the preceding Pliocene, the previously isolated North and South American continents were joined by the Isthmus of Panama, causing Great American Interchang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anglian Stage
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. The Anglian Stage is correlated to Marine Isotope Stage 12 (MIS 12), which started about 478,000 years ago and ended about 424,000 years ago. Lisiecki, L.E. (2005Ages of MIS boundaries. Boston MA:Boston University Description The Anglian stage has often been correlated to the Elsterian Stage of northern Continental Europe and the in the |
Beestonian Stage
The Beestonian Stage is an early Pleistocene stage used in the British Isles. It is named after Beeston Cliffs near West Runton in Norfolk where deposits from this stage are preserved. The Beestonian precedes the Cromerian Stage and follows the Pastonian Stage. This stage consists of alternating glacial and interglacial phases instead of being a continuous glacial epoch. It is equivalent to Marine isotope stages 22 to (60?).Walker, M., 2005, ''Quaternary Dating Methods'', John Wiley & Son, Chichester, United Kingdom. Gibbard, P.L., S. Boreham, K.M. Cohen and A. Moscariello, 2007''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 Beestonian Stage and Marine Isotope Stage 22 ended about 866,000 years ago. Lisiecki, L.E., 2005Ages of MIS boundaries. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cromerian Stage
The Cromerian Stage or Cromerian Complex, also called the Cromerian (german: Cromerium), 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 (german: Kromer-Warmzeit). It is now known that the Cromerian consisted of multiple glacial and interglacial periods. Chronology The core of the Cromerian is the first half of the Middle Pleistocene stage (Ionian) approximately 800-500 ka ago, just before the Anglian glaciation. In term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoxnian Stage
__NOTOC__ The Hoxnian Stage was a middle Pleistocene stage (Pleistocene from million to 11,700 years BP) 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 (MIS 11). Marine Isotope Stage 11 started 424,000 years ago and ended 374,000 years ago. Lisiecki, L. E. (2005)Ages of MIS boundaries.http://www.lorraine-lisiecki.com/stack.html LR04 Benthic Stack] Boston University, Boston, MA The Hoxnian is divided into sub-stages Ho I to Ho IV. History The Hoxnian Stage is named after Hoxne in the English county of Suffolk where some of the deposits created were first found. It was identified and dated with palynology or pollen evidence in the biostratigraphy and later updated with aminostratigraphic techniques. Based on stratigraphic information the Hoxnian happened after the Anglian glacial as Anglian soil is frequently found underneath Hoxnian deposits. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wolstonian Stage
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 Eemian Stage in Europe and follows the Hoxnian Stage in the British Isles. It is also approximately analogous to the Warthe and Saalian stages in northern Europe; the Riss glaciation in the Alps; and the Illinoian Stage in North America. It is equivalent to Marine isotope stages (MIS) 10 through 6. MIS 10, 8 and 6 were glacial periods and 9 and 7 were interglacials. It is named after Wolston in the English county of Warwickshire. Description The Wolstonian Stage is a middle Pleistocene stage of the geological history of Earth that precedes the Ipswichian Stage (Eemian Stage in Europe) and follows the Hoxnian Stage in the British Isles. The Wolstonian Stage apparently includes three periods of glaciation. The Wolstonian Stage is temporally analogous to the Warthe Stage and Saalian Stage in northern Europe and the Riss glaci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Isles
The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles, and over six thousand smaller islands."British Isles", ''Encyclopædia Britannica''. They have a total area of and a combined population of almost 72 million, and include two sovereign states, the Republic of Ireland (which covers roughly five-sixths of Ireland), and the United Kingdom of Great Britain and Northern Ireland. The Channel Islands, off the north coast of France, are normally taken to be part of the British Isles, even though they do not form part of the archipelago. The oldest rocks are 2.7 billion years old and are found in Ireland, Wales and the northwest of Scotland. During the Silurian period, the north-western regions collided with the south-east, which had been part of a separate continental landmass. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and greenhouse periods, during which there are no glaciers on the planet. Earth is currently in the Quaternary glaciation. Individual pulses of cold climate within an ice age are termed ''glacial periods'' (or, alternatively, ''glacials, glaciations, glacial stages, stadials, stades'', or colloquially, ''ice ages''), and intermittent warm periods within an ice age are called '' interglacials'' or ''interstadials''. In glaciology, ''ice age'' implies the presence of extensive ice sheets in both northern and southern hemispheres. By this definition, Earth is currently in an interglacial period—the Holocene. The amount of anthropogenic greenhouse gases emitted into Earth's oceans and atmosphere is predicted to prevent the next glacial period for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Isotope Stage
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 reflecting changes in temperature derived from data 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. The MIS timescale was developed from the pioneering work of Cesare Emiliani in the 1950s, and is now widely used in archaeology and other fields to express dating in the Quaternary period (the last 2.6 million years), as well as providing the fullest and best data ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Illinoian Glacial Lobe
The Illinoian Stage is the name used by Quaternary geologists in North America to designate the period c.191,000 to c.130,000 years ago, during the middle Pleistocene, 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.Willman, H.B., and J.C. Frye, 1970, ''Pleistocene Stratigraphy of Illinois.'' Bulletin no. 94, Illinois State Geological Survey, Champaign, Illinois. It occurs at about the same time as the penultimate glacial period. Definition At its type exposure in Peoria County, Illinois, the Illinoian deposits consist of three till members of the Glasford Formation. They overlay Pre-Illinoian tills of the Banner Formation, in which the Yarmouth Soil (paleosol) has deve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
