WARMAN, COLUMBIA UNIVERSITY, COURTESY EMILIO SEGRE VISUAL ARCHIVES / AMERICAN INSTITUTE OF PHYSICS / SCIENCE PHOTO LIBRARY WARMAN, COLUMBIA UNIVERSITY, COURTESY EMILIO SEGRE VISUAL ARCHIVES / AMERICAN INSTITUTE OF PHYSICS / SCIENCE PHOTO LIBRARY
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William Maurice Ewing (1906-1974), US geophysicist, working with graphs. Ewing discovered the thickness of the Earth's crust beneath the oceans. Using marine seismic techniques, Ewing showed that the oceanic crust was only 5-8 kilometres thick as compared with the 40 kilometres beneath the continents. Ewing discovered the global extent of mid-ocean ridges, and showed that the depth of sediment on the ocean floor grows with increasing distance from a ridge. These observations provided evidence in support of the theory of plate tectonics. Photographed at the Lamont-Doherty Earth Observatory (LDEO), Palisades, New York, USA.
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