After a childhood in the field with her father, a soil surveyor for the U.S. Department of Agriculture, Marie Tharp had to overcome many gender-based road blocks before becoming an oceanographic cartographer.
After earning degrees in petroleum geology and mathematics she accepted a job at Lamont Geological Laboratory of Columbia University where she began a lifelong collaboration with geologist Bruce Heezen. With the rise of cold war tensions and the use of submarines in warfare, having an accurate map of the ocean floor was a high priority and the team began working on this project.
Due to superstitious beliefs at the time, Tharp was not allowed to travel as part of the expedition team but had to rely on the data sent back to her to complete her work. With this raw data she would calculate, interpret, and visualize the ocean floor.
In 1952 she was preparing a map of a section of the Atlantic Ocean but as she mapped the continental shelf, discovered in the 1870s, the data showed something much more unexpected. Running along the mountain range was a strange v-shaped gap – evidence of a rift valley – a place where magma emerged from inside the earth forming new crust and thrusting the land apart. While the idea of continental drift had been proposed in 1926, the scientist promoting it was laughed out of the meeting he spoke at and the idea was dismissed.
Nonetheless, Tharp knew she had found a rift valley and took her findings to Heezen who dismissed her map telling her it was “girl talk” and to go back and start again. So she did and she came to the same conclusion and as the pair worked together to map the entire ocean they discovered the largest single geographic feature on the planet: the Mid-Ocean Ridges, a 40,000 mile underwater mountain range wrapping around the Earth likes the seams on a baseball.
In 1997 the Library of Congress named her one of the four greatest cartographers of the 20th Century and her work as included in an exhibit alongside the original rough draft of the American Declaration of Independence.
Written by Angela Goad