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Article History. Laurentide Ice Sheet, principal glacial cover of North America during the Pleistocene Epoch (about 2,600,000 to 11,700 years ago). At its maximum extent it spread as far south as latitude 37° N and covered an area of more than 13,000,000 square km (5,000,000 square miles). In some areas its thickness reached 2,400–3,000 ...
- Pleistocene Events and Environments
The growth of large ice sheets, ice caps, and long valley...
- Pleistocene
The Pleistocene Epoch is best known as a time during which...
- Pleistocene Events and Environments
- Fossils as Clues
- Rocks as Clues
- Maps as Pictures
A closer look at these fossils will tell even more. Their distribution identifies the ancient areas of land and sea, and also determines the approximate shoreline. The distribution of living forms shows that thick-shelled fossil animals once lived in shallow water close to shore, where their shells were built to withstand the surging and pounding o...
Before the 1830's, geologists were uncertain about the origin of deposits of boulders crudely mixed with sand, silt, and clay which cover large portions of Europe and North America. Associated with these deposits were large, striated boulders (some as large as a house) and scratched and grooved bedrock surfaces. Some naturalists had speculated that...
Fossils, the size and sorting of grains, and the direction of cross beds in rocks are only a few of many such clues, although they are the most useful, that geologists use to reconstruct paleogeography. By using these data, geologists reconstruct pictures of the geography of the North American Continent during each of the various periods of geologi...
The growth of large ice sheets, ice caps, and long valley glaciers was among the most significant events of the Pleistocene. During times of extensive glaciation, more than 45 million square km (roughly 17,400,000 square miles), or about 30 percent of Earth’s land area, was covered by glaciers, and portions of the northern oceans either were frozen over or had extensive ice shelves.
The Pleistocene Epoch is best known as a time during which extensive ice sheets and other glaciers formed repeatedly on the landmasses and has been informally referred to as the “Great Ice Age.” The timing of the onset of this cold interval, and thus the formal beginning of the Pleistocene Epoch, was a matter of substantial debate among geologists during the late 20th and early 21st centuries.
The Pleistocene (/ ˈplaɪstəˌsiːn, - stoʊ -/ PLY-stə-seen, -stoh-; [ 5 ][ 6 ] often referred to colloquially as the Ice Age) 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 ...
Sep 14, 2018 · Often occurring over geologically short (<10 4 years) time scales, large-scale paleo-geographic changes related to Pleistocene ice sheets significantly affected the evolution and migration ...
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Jul 12, 2019 · Late Pleistocene archaeology south of the ice sheets. In North and South America, a number of sites dating between ∼15.5 and ~13.3 ka ago provide evidence of the first human presence south of the ice sheets (Fig. 4). At these sites, artifacts are found in undisturbed geological contexts that are well dated.
