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2006-12-31 03:21:55 · 1 answers · asked by hippopotamus232002 1 in Science & Mathematics Earth Sciences & Geology

1 answers

Probably best credited to American geologist Harry H. Hess.-ideas of plate tectonics first published 1962-(written 1960),

from USGS pub, This Dynamic Earth: http://pubs.usgs.gov/gip/dynamic/developing.html
"If the Earth's crust was expanding along the oceanic ridges, Hess reasoned, it must be shrinking elsewhere. He suggested that new oceanic crust continuously spread away from the ridges in a conveyor belt-like motion. Many millions of years later, the oceanic crust eventually descends into the oceanic trenches -- very deep, narrow canyons along the rim of the Pacific Ocean basin. According to Hess, the Atlantic Ocean was expanding while the Pacific Ocean was shrinking. As old oceanic crust was consumed in the trenches, new magma rose and erupted along the spreading ridges to form new crust. In effect, the ocean basins were perpetually being "recycled," with the creation of new crust and the destruction of old oceanic lithosphere occurring simultaneously. Thus, Hess' ideas neatly explained why the Earth does not get bigger with sea floor spreading, why there is so little sediment accumulation on the ocean floor, and why oceanic rocks are much younger than continental rocks."

2007-01-01 16:15:48 · answer #1 · answered by luka d 5 · 0 0

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