Marie Tharp

Women in STEM
Women in STEM
Marie Tharp

Birth: July 30, 1920

Death:  August 23, 2006 

Specialty: Geologist and oceanographic cartographer

Major Contributions:

Co-discoverer of the backbone of earth, the Mid-Ocean Ridges

Created the first physiographic maps of seafloor

Awarded the 1st annual Lamont-Doherty Heritage Award

Image: Wikimedia

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 roadblocks before becoming an oceanographic cartographer.

After earning degrees in petroleum geology and mathematics she accepted a job at the Lamont Geological Observatory 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 the 1950s 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.

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. In 2009, Google Earth added the Marie Tharp Historical Layer allowing users to see her ocean map in the interface and in 2022 a Google Doodle sharing her story was released. The next year it was announced that a US Naval ship would be renamed the USNS Maria Tharp in her honor.

Written by Angela Goad


Mental Floss: How One Woman’s Discovery Shook the Foundations of Geology Marie Tharp

Remembered: Marie Tharp, Pioneering Mapmaker of the Ocean Floor

Wikipedia: Marie Tharp

Google Doodle: Marie Tharp

See Also:

World Oceans Day

Science Friday: Writing Women Back Into Science History