Encyclopedia

Tharp, Marie

Tharp, Marie, 1920–2006, American oceanographer and cartographer. A geologist (Univ. of Michigan, M.A., 1944) with experience in mapping, she came to Columbia as a geology research assistant in 1948, retiring in 1983. Painstakingly converting oceanographic soundings to physiographic maps of the North Atlantic Ocean floor, Tharp, working with Bruce Heezen, identified (1952) the Mid-Atlantic ridge and rift valley; when Heezen's group confirmed that seismic activity along the ridge was centered on the rift, it provided solid evidence of seafloor spreading and plate tectonics. Tharp and Heezen's work mapping the oceans ultimately led to the discovery of a 40,000 mi (64,000 km) panoceanic underwater ridge, made visible in their World Ocean Floor map published (1977) by the Office of Naval Research.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2007, Columbia University Press. All rights reserved.

More on Marie Tharp from Fact Monster:

  • OCEAN FLOOR - Just a century ago, the ocean floor was largely unknown. Now we know that the deep oceans have features such as mountains, deep valleys, and vast plai
  • EARTH - The rocky ball that forms our world is one of nine planets in the Solar System. Earth is a sphere, with a slight bulge in the middle at the Equator, a

See more Encyclopedia articles on: Geology and Oceanography: Biographies