Who was Marie Tharp?

Born in Michigan in 1920, Marie Tharp was an influential mapmaker and geologist. According to historian Jerry Brotton, Tharp is probably the most important woman in the mapmaking industry in the 20th century.


She was effectively responsible for the discovery of tectonic plate shift and development of the theory of continental drift – a seemingly heretical theory at the time, which we now accept as absolute truth.

Jerry Brotton, expert in the history of mapmaking and professor of Renaissance Studies at Queen Mary, University of London
Jerry Brotton chooses Marie Tharp (Photo by Getty)

Marie Tharp’s life

Working in a traditionally male-dominated field, Tharp made a name for herself following the Second World War, when she began working at Columbia University, at the famous Lamont-Doherty Earth Observatory.

Alongside her colleague, Bruce Heezen, Tharp crunched the data from sonar readings from US military ships in the Atlantic.

Due to the misogynistic nature of society at the time, Brotton explains, Tharp was not allowed on the boats herself, but Heezen fed her the data from his explorations, and from this, Tharp proposed the idea that the continents and ocean floor were ceaselessly moving. Her argument was rejected by most in the field at the time, including Heezen. When she began to map plate shifts in the Atlantic, Heezen allegedly erased all her work.

Despite this setback, Tharp continued mapping her data and developing her theories, proving irrefutably that tectonic plate shift existed. By the late 1950s, Tharp had persuaded Heezen that her theory was correct, and together, they developed precise scientific maps of the ocean floors – called physiographic maps – which were published under Heezen’s name only.

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In the 1960s, Tharp was finally allowed out on boats herself, where she could be in the thick of data collection alongside her male counterparts. However, her name did not start appearing on her maps until the early 1970s.

A key moment in Tharp’s career was the creation of the World Ocean Floor Map in 1977, Jerry explains. Still working out of Columbia University, Tharp had created a map of all the different ocean floors with Heezen. Tragically, Heezen died before the map’s publication, but in 1977, the National Geographic sponsored the map, naming it the Heezen-Tharp map.

Though still overshadowed by Heezen’s name, Tharp’s work with this map was highly impactful and she finally began to receive recognition for her influence. In the latter stages of her career, she was recognised by the US Library of Congress and awarded a medal for her services to the geological and geographical field. However, despite this, Brotton explains, she has still not received the public recognition she deserves for her work.

Why does Marie Tharp deserve her 15 minutes of fame?

Marie Tharp deserves her 15 minutes of fame, says Brotton, because she was undefeatable in her work. “She faced so much misogyny throughout her career,” he says, “but continued to work tirelessly on her geological theories and mapmaking, contributing highly influential thoughts to the field.”

Tharp was never working for her own self-aggrandisement, Brotton says. “She accepted that she couldn’t control the misogyny she faced, but she could control her work, and with this focus on the need for us to understand the world we live in, she contributed some of the most significant scientific discoveries of the 20th century.”

Jerry Brotton is an expert in the history of mapmaking and professor of Renaissance Studies at Queen Mary, University of London. His books include A History of the World in Twelve Maps (Penguin, 2012)

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Article compiled by Isabel King


Jerry Brotton is professor of Renaissance studies at Queen Mary University of London