How Marie Tharp Changed Geology

June 23, 2017

By: Alicen Ricard

It's strange to think of a time when we didn't know that the ocean bottom isn't flat, but that time did exist. When scientist Alfred Wegener first proposed his theory of continental drift, no one believed him and thought he couldn't possibly be correct. That is, until Marie Tharp discovered the 10,000-mile-long Mid-Atlantic Ridge, and proved him right. 

Source: Wikipedia

Marie Tharp was an American Geologist who changed the way we look at the ocean floor. She didn’t know that she wanted to be a scientist—she was going to attend St. John’s College in Annapolis, Maryland, for literature. However, at that time women weren't allowed to attend, so she ended up attending Ohio University instead. Her father was a soil surveyor, and it was there she ended up following in his footsteps. She enrolled in a petroleum geology program, but after a while she didn't find it fulfilling enough, so she went back to school at Tulsa University. She was able to get her Master's in geology in the 1940s while the American troops were away fighting World War II. This was a rarity for women in her time—from 1920 to 1970 women received less than four percent of doctorates. 

It was then that her life took a turn that would change it forever, when she got a job as an assistant to Bruce Heezen at the Lamont Geological Laboratory at Columbia University. The head of the lab, Maurice "Doc" Ewing, had the scientists in his lab go out and study the bottom of the ocean floor, but Tharp wasn't allowed since she was a woman. It was considered bad luck to have women on these expeditions, and Ewing didn’t make anything overly accommodating for women.

Source: Smithsonian Magazine

While everyone was out exploring, Tharp was left behind at the lab to process data. She converted them into profiles of the ocean floor and confirmed that the bottom of the ocean was not flat. She found plates which moved apart and split open, causing the ocean floor to form a valley. Maybe Alfred Wegner wasn't crazy after all. Tharp started making maps to expand these theories—mapping out peaks and valleys of the Atlantic Ocean. 

Much like they did with Alfred Wegner, people didn't believe Tharp either. Even Heezen didn't believe her at first (though he later tried to take credit for her work). Then Howard Foster started plotting the epicentres of earthquakes and seismic activity in the Atlantic, and Tharp noticed a pattern. The epicentres all coincided with where the rift valleys were. They started studying more and discovered there was a link between mid ocean ridges and epicentres of earthquakes. Tharp finally had someone on her side. That wasn't the end of the skepticism, though. Explorer Jacques Cousteau still thought they were wrong, and led an expedition to try to prove it. Much to his dismay, his cameras found evidence that Tharp was correct.

Source: GIS Lounge

Tharp was an inspirational woman who helped shape the way we see geology. In her book she stated, "Not too many people can say this about their lives: The whole world was spread out before me (or at least, the 70 percent of it covered by oceans). I had a blank canvas to fill with extraordinary possibilities, a fascinating jigsaw puzzle to piece together: mapping the world’s vast hidden seafloor. It was a once-in-a-lifetime—a once-in-the-history-of-the-world—opportunity for anyone, but especially for a woman in the 1940s." She overcame the odds and discovered some cool science while she was at it.

To find out more about Marie Tharp check out this video that inspired this post. Follow us on Facebook and Twitter to share more cool facts about this awesome cartographer.