Most of us learn about the Earth’s shifting tectonic plates by middle school. But in Marie Tharp’s time, this fact we now take for granted was a groundbreaking, radical concept…and one that had to overcome gender bias.
In 1957, Tharp, a geologist and oceanographic cartographer, and her colleague Bruce Heezenhad published the first map of the Atlantic. Tharp endured considerable challenges due to sexism. For one thing, women weren’t allowed on the ships that collected the seafloor data to make the maps in the first place. So Tharp spent hours at a desk translating thousands of sonar readings from those ships that wouldn’t take her.
Her hand-drawn maps eventually revealed that the seafloor was covered in canyons, ridges, and mountains…all of which suggested that at some point, pieces of the Earth had moved.
This was important because the previous mainstream view was that the ocean floor was flat and motionless. However, Tharp’s findings supported Alfred Wegener highly controversial “continental drift theory,” which first suggested that the present-day continents once fit together as a supercontinent, aka Pangaea, in 1912.
Of course, we now know Pangea to be a real thing, but not long ago, this idea was considered heresy. And so when Tharp reintroduced it through her findings, Heezen dismissed it as “girl talk,” or an “old wives’ tale,” depending on where you look. Either way, the context reads pretty clear.
Heezen would come around in time, but the duo would also have to sway the rest of the scientific community. Keep in mind, the supposed peaks and valleys were, at this point, only conjecture. However, in 1959, when Jacques Cousteau, determined to prove Tharp wrong, lowered his underwater camera with 16-millimeter film into the middle of the ocean, and a valley was indeed there…it became fairly evident that she was right.
Though it was primarily Tharp’s groundbreaking findings that paved the way for our new understanding, she was still seen as “merely a technician,” and therefore Heezen took the lion’s share of the credit as they continued their work together, which eventually included mapping all of the world’s oceans. She wouldn’t even be allowed to set foot on a research cruise until 1968.
But proving her tenacity, Tharp was nevertheless able to make a life-changing scientific contribution in spite of it all, a) because she was resourceful, and b) because she believed in the importance of her work. As she herself said,
“I had a blank canvas to fill with extraordinary possibilities, a fascinating jigsaw puzzle to piece together. 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.”
In time, Tharp would get some recognition. In 1997, the Library of Congress named her one of the greatest cartographers of the 20th century. And in 2023, National Geographic awarded her the highly prestigious Hubbard Medal.
And of course, every time we look at a map, we witness a bit of her signature. Still, one can’t help but wonder what other women from history secretly shaped the way we view the world today, and the pains they took to do so.
