glacial stage


glacial stage

      in geology, a cold episode during an ice age, or glacial period. An ice age (q.v.) is a portion of geologic time during which a much larger part of the Earth's surface was covered by glaciers than at present. The Pleistocene Epoch (1.6 million to 10,000 years ago) is sometimes called the Great Ice Age, or Glacial Age, because during that epoch, ice sheets developed periodically over vast areas of northern and mid-latitude North America and Eurasia. The advance of these ice sheets would be followed some tens of thousands of years later by their melting away and then by another advance. This cyclical process occurred several times during the Pleistocene Epoch, and the successive glacial advances and retreats, which were evidently responses to fluctuations of the Earth's climate, are known respectively as glacial stages and interglacial stages. The interglacial stages represent periods when the Earth's climate seems to have been as warm as it is at present.

      The succession of glacial stages can be recognized in sequences of geologic strata containing till (i.e., rock, sand, and clay particles deposited by glaciers), with each till layer representing a stage, or episode, when the ice sheets were much more extensive than they are today. Some of the tills are separated from over- and underlying ones by ancient soils or other sediments of nonglacial character. The intervals corresponding to these features are interglacials.

       Pleistocene glacial and interglacial episodes in central North America and Alpine EuropePleistocene strata have been much studied in North America and Europe. Each successive glaciation represented in these strata has been identified and named, though the same glacial episode usually bears a different name in North America than in Europe. Indeed, three regions of Europe have been differentiated, and all have different names for what is essentially the same worldwide sequence of glacial and interglacial stages. The main stages in North America and Alpine Europe from the Pleistocene on are given in the Table (Pleistocene glacial and interglacial episodes in central North America and Alpine Europe).

      Most major glaciations were themselves composed of smaller pulses of glacial advance alternating with similar periods of retreat. These subcycles, called substages, are known with certainty only for the world's last glacial stage, i.e., the Wisconsin (Wisconsin Glacial Stage) in North America and the Würm (Würm glacial stage) in Alpine Europe. The last of this stage's three or four substages, called the Mankato in North America and Würm IV in Europe, ended about 10,000 years ago, by which time the world's glaciers had retreated to their present-day dimensions. See also Pleistocene Epoch.

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Universalium. 2010.

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  • Saale Glacial Stage — ▪ geology       division of Pleistocene deposits and time in northern Europe (the Pleistocene Epoch began about 1,600,000 years ago and ended about 10,000 years ago). The Saale Glacial Stage followed the Holstein Interglacial Stage and preceded… …   Universalium

  • Wisconsin Glacial Stage — ▪ geology       most recent major division of Pleistocene time and deposits in North America (1,600,000 to 10,000 years ago). It was named for rock deposits studied in the state of Wisconsin. At least the last half, and possibly all, of the… …   Universalium

  • Riss Glacial Stage — ▪ geology       major division of Pleistocene time and deposits (1,600,000 to 10,000 years ago) in Alpine Europe. The Riss Glacial Stage, during which mountain glaciers descended from the highlands, followed the Mindel Riss Interglacial Stage and …   Universalium

  • Weichsel Glacial Stage — ▪ paleontology also called  Vistula Glacial Stage,         major division of late Pleistocene deposits and time in western Europe (the Pleistocene Epoch began about 1,600,000 years ago and ended about 10,000 years ago). The Weichsel Glacial Stage …   Universalium

  • Günz Glacial Stage —       major division of Pleistocene time and deposits in the Alpine region of Europe (the Pleistocene Epoch began about 1,600,000 years ago and ended about 10,000 years ago). The Günz Glacial Stage is one of the early recognized divisions that… …   Universalium

  • Elsterian Glacial Stage — ▪ Pleistocene deposits and time, northern Europe       major division of Pleistocene deposits and time in northern Europe (the Pleistocene Epoch began about 2,500,000 years ago and ended about 10,000 years ago). The Elsterian followed the… …   Universalium

  • Würm glacial stage — ▪ geology       major division of late Pleistocene deposits and time in Alpine Europe (the Pleistocene epoch began about 1,600,000 years ago and ended about 10,000 years ago). The Würm glacial stage followed the Riss Würm interglacial and is… …   Universalium

  • Mindel Glacial Stage — ▪ geology       major division of Pleistocene time and deposits in Alpine Europe (the Pleistocene epoch began about 1,600,000 years ago and ended about 10,000 years ago). The Mindel Glacial Stage is part of the early geologic scheme (c. 1900)… …   Universalium

  • Donau Glacial Stage — ▪ geology       major division of early Pleistocene time and deposits in the Alpine region of Europe (the Pleistocene Epoch dates from 1,600,000 to 10,000 years ago). The Donau Glacial Stage preceded the Donau Günz Interglacial Stage and is… …   Universalium

  • Eburon glacial stage — ▪ geology       division of Pleistocene time in northern Europe (the Pleistocene epoch began about 1,600,000 years ago and ended about 10,000 years ago). The Eburon glacial stage preceded the Waal interglacial stage and followed the Tegelen… …   Universalium


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