Historical Geology Understanding Our Planet\'s Past

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last 10 million years and might be buoyed by a mass of hot rock in the upper mantle. In the Pacific Northwest of the United Stat ...

ancy uplifted the Himalaya Mountains and the broad Tibetan Plateau (Fig. 186), the size of which has not been equaled on this pl ...

ranges on the northern and southern flanks (Fig. 187). The contact between the continents initiated a major mountain building ep ...

the Nazca plate beneath the South American plate. By the time all the con- tinents had wandered to their present positions and a ...

tica drifted over the South Pole, it acquired a permanent ice sheet that buried most of its terrain features (Fig. 188). The Mid ...

warm Pacific currents, this might have initiated the Pleistocene glacial epoch. Never before have permanent ice caps existed at ...

Aral Seas, called the Paratethys. It covered much of eastern Europe. About 15 million years ago, the Mediterranean separated fro ...

T his chapter examines the Ice Ages and the present interglacial during the Quaternary period. The Quaternary, from 3 million ye ...

100,000 years. Once in place, the glaciers became self-sustaining by control- ling the climate.Then, mysteriously in only a few ...

Figure 190The human ancestry probably began with Australopithecus. (Photo courtesy National Museums of Canada) Historical Geolog ...

About 2.5 million years ago, a sudden change in climate spurred the evo- lution of the first humans.The drying of the African cl ...

fishing the rivers and hunting reindeer and other animals. As with modern populations of Arctic peoples, human ancestors inhabit ...

THE PLEISTOCENE ICE AGES For more than 200 million years from the end of the Permian to about 40 million years ago, no major ice ...

Some 10 million cubic miles of water were tied up in the continental ice sheets. They covered about one-third of the land surfac ...

migration of species, including humans, to various parts of the world.The great weight of the ice sheets caused the continental ...

Figure 194An exposure of loess standing in vertical cliffs,Warren County, Mississippi. (Photo by E.W. Shaw, courtesy USGS) Histo ...

between 16,000 and 12,000 years ago, when average global temperatures increased about 5 degrees Celsius to nearly present-day le ...

Historical Geology meltwater formed in a bedrock depression carved out by glaciers, sat at the edge of the retreating ice sheet ...

Free ebooks ==> http://www.Ebook777.com water laden with sediment surged along the Mississippi River toward the Gulf of Mexic ...