Marie Tharp

Marie was an American geologist and oceanic cartographer who made paradigm-shifting discovery by making detailed maps of the ocean floor.

Marie Tharp (1920–2006), Sci-Illustrate Stories.

Featuring artwork by Miler Ximeno Lopez and words by Dr. Sumbul Jawed Khan, Sci-Illustrate Stories. Set in motion by Dr. Radhika Patnala.

Marie Tharp (1920- 2006) made transformative contributions to the field of Earth Science and the year 2020 was celebrated as the centennial year of Marie’s birth.

Until the early 20th century the oceans were considered to be just featureless pools of water. Thanks to Marie’s powerful maps we were given the first detailed visual of the ocean floor’s rich topography. These maps showed that just like the land mass these massive water bodies have a complex architecture and are made up of mountains, and valleys, and plains.

Early life

Marie was born in Ypsilanti, Michigan, the only child of Bertha Louise Tharp (nee Newton) and William Edgar Tharp. Her mother was a schoolteacher, and father was a soil surveyor at the U.S. Department of Agriculture, Bureau of Chemistry and Soils, whose job took him into different states across the country. Young Marie would often accompany him in his soil collecting trips, an activity that might have kindled her interest in geology, although unbeknownst to her at the time.

“I guess I had map-making in my blood, though I hadn’t planned to follow in my father’s footsteps.”

Marie’s parents were very supportive and encouraging, and gave her the freedom to choose her own course in life. Her mother, who Marie was very close to, passed away when Marie was 15 years old. Her father’s constantly moving job meant that Marie had attended two dozen schools by the time she graduated high school, which also meant that she couldn’t have any long lasting friendships. But she always remained close to her family.

How a woman became a Geologist (and not a teacher, a secretary or a nurse)

It was a time when women were only expected to have a career as a teacher, a secretary, or a nurse, and discouraged from having any further aspirations. When Marie started college at Ohio University in 1939, she was unsure about her career, but got interested in science, and for the first time in geology, through a course that she was taking. During this time she also undertook a map-drafting project that came in handy later in life.

As fate would have it, Marie’s life turned around when Pearl Harbor was attacked in 1941 and young men were drafted to fight in World War II, resulting in a shortage of male students at universities. This led University of Michigan’s Geology department to invite women applicants for a Master’s degree, with a promised job in the petroleum industry upon completion. Marie jumped on the opportunity, and later observed that-

“I never would have gotten the chance to study geology if it hadn’t been for Pearl Harbor. Girls were needed to fill the jobs left open because the guys were off fighting.”

Marie Tharp as a young student. Image source: Lamont-Doherty Earth Observatory and the estate of Marie Tharp

She started a job at the Stanolind Oil and Gas Co. in Tulsa, Oklahoma, in 1945 as a junior geologist after her M.Sc. However, since women were not allowed in the field she was relegated to routine administrative work. Seeking to do something more intellectually challenging, she enrolled at the University of Tulsa for a degree in Mathematics. Still not satisfied and looking for something more exciting Marie moved to New York in 1948

Mapping Ocean Floors- a Tharp-Heezen collaborative project

Marie’s unique background in geology, mathematics, and drafting, landed her at the Lamont Observatory at Columbia University (now called the Lamont-Doherty Earth Observatory) in 1949. Despite her experience and educational credentials she was hired to assist other male graduate students. She started assisting Bruce Heezen, a talented graduate student, in mapping the ocean floors that turned into a lifelong collaboration.

Marie Tharp working on her maps. Marie spent hours translating souding data into 3-D topographical information. Image source: Lamont-Doherty Earth Observatory and the estate of Marie Tharp

Being a woman Marie was not allowed to go on ships (since having women onboard was considered an ill omen), so Bruce went on explorations of the Atlantic Ocean, collecting echo sound recording data (a kind of sonar technique) that measured the depth of the sea. The readings were sent to Marie who had the arduous task of reconstructing the relief of the ocean floor through careful interpretation from reels of paper. She would first convert it into 2-dimensional maps, and then superimpose it with the longitude and latitude information of the region to complete a 3-dimensional picture.

By 1952 she was a master of her craft, and made a landmark discovery. From her calculations it appeared that there was a rift in middle of the Mid-Atlantic ridge (the mountain range running in the middle of the Atlantic ocean), which means that the mountain peak had a valley like feature. The rift had formed due to a crack in the earth’s mantle from where molten material was seeping out and solidifying to into new material, and in the process moving the surface beyond. This was a clear indicator of presence of moving tectonic plates and evidence for Continental Drift.

Marie Tharp and Bruce Heezen looking through a transparency. Image source: Lamont-Doherty Earth Observatory and the estate of Marie Tharp

Bruce Heezen immediately dismissed the idea as ‘Girl Talk’. Not only what Marie was suggesting was out of the realm of imagination for the science community, but it was also proving the theory of continental drift, an idea then shunned by American scientists. Avoiding being sacrilegious, Bruce rejected her conclusion. But Marie did not give up. She went back to collect more data, and added the information of earthquake epicenters to her map, which neatly coincided with the ridge, proving beyond doubt the existence of the ridge. Bruce eventually turned around, and they published the results in 1957 in ‘The Floors of the Oceans: I. The North Atlantic’.

Scientists were still skeptical about the ridge. However further evidence came from very unexpected quarters! Jacques Cousteau, a French explorer and a skeptic of the theory, wanted to prove Marie and Bruce wrong and set out on an expedition to film the rift valley. A video camera was hung on his ship that went deep inside the ocean and recorded visuals of the ocean floor. He presented this data at the 1959 International Oceanographic Congress in New York. This was the conclusive proof. The scientific community conceded that indeed Marie’s maps were accurate.

Creating the first World Ocean Floor Map- a paradigm shifting research

Marie and Heezen’s discovery of the Mid-Atlantic Ridge provided evidence for other major discoveries in geology, the Plate Tectonic Theory and Continental Drift. Their most remarkable innovation was using a ‘physiographic method’ of map-making, which incorporated a three-dimensional drawing to give a better visual of the space.

They continued their work, and discovered that the ridge can be found under the ocean around the globe, demarcating the earth’s tectonic plates. They published a second map showing the South Atlantic ocean floor in 1961, followed by the map of the Indian ocean floor in 1964. By the 1970’s the presence of tectonic plates and continental drift were accepted paradigms of earth science.

They collaborated with the Austrian painter and cartographer Heinrich Berann to create a world map depicting the ocean floors. Heinrich was well-known, and created map paintings for National Geographic Society. The three finally published this map in 1977 titled ‘World Ocean Floor Panorama’.

Marie Tharp and Bruce Heezen were life long collaborators creating detailed sea floor maps of oceans across the globe. Image source: Lamont-Doherty Earth Observatory and the estate of Marie Tharp

Recognition and lasting legacy

Marie and Bruce made a formidable team, who would get on each other’s nerves but then soon put their brilliant minds to work in making geological breakthrough. After Bruce passed away in 1977 due to a sudden heart attack while he was on a research cruise on a submarine, Marie did not continue her work. She chose instead to consolidate her and Bruce’s legacies, struggling to give its due place in history and saving it from becoming just a geological fact embedded in textbooks.

Marie Tharp with her maps. Image source: Lamont-Doherty Earth Observatory and the estate of Marie Tharp

While not getting due credit during her scientific career, she gained recognition later on receiving the Outstanding Achievement Award from the Society of Women Geographers in 1996, the Library of Congress’ Phillips Society honored her as one of the 20th Century’s Outstanding Cartographers in 1997, she was awarded the Women Pioneer in Oceanography Award by the Woods Hole Oceanographic Institution in 1999, the Lamont-Doherty Heritage Award in 2001. In 2004 Lamont Observatory created the Marie Tharp Visiting Fellowship Program for promising female researchers.

Marie’s unique skill of combining scientific knowledge with a creative imagination was instrumental in opening the eyes of the world to sights unseen and concepts unimagined. In that sense, what she created is truly unique, groundbreaking, and best expressed by herself in the following words-

“Establishing the rift valley and the mid-ocean ridge that went all the way around the world for 40,000 miles — that was something important. You could only do that once. You can’t find anything bigger than that, at least on this planet.”


1920- Born in Ypsilanti, Michigan, to Bertha Louise Tharp and William Edgar Tharp

1939- 1943- Bachelor’s degree from Ohio University in English and music

1943- 1945- Master’s in Geology from University of Michigan at Ann Arbor

1948- Graduated with a second Master’s degree from Tulsa University, Oklahoma in mathematics

1948- Married David Flanagan; they later divorced in 1952

1949- Joined the Lamont Geological Observatory (now the Lamont-Doherty Earth Observatory at Columbia University)

1952- Marie discovers the Mid-Atlantic Ridge and Rift Valley

1957- Map of North Atlantic Ocean published by the Geological Society of America called ‘The Floors of the Oceans: I. The North Atlantic’

1977- Tharp and Heezen publish the first map of the ocean’s floor, called ‘World Ocean Floor Panorama’ painted by Heinrich Berann

1978- Awarded the Hubbard Medal by National Geographic Society

1997- Named one of the four greatest cartographers of the 20th century by the Library of Congress.

2001- Awarded the first Lamont-Doherty Heritage Award

2006- Passed away on August 23 due to cancer in Nyack, New York

References / Further reading:

About the author:


Content Editor,Women In Science, Sci-Illustrate Stories.

Dr. Khan received her Ph. D. in Biological Sciences and Bioengineering from the Indian Institute of Technology Kanpur, where she studied the role of microenvironment in cancer progression and tumor formation. During her post-doctoral research at the University of Illinois at Urbana-Champaign, Dr. Khan investigated the gene regulatory networks that are important for tissue regeneration after damage or wounding. Dr. Khan is committed to science outreach activities, to make scientific research understandable and relatable to the non-scientific community. She believes it is essential to inspire young people to apply scientific methods to tackle the current challenges faced by humanity.

About the artist:


Contributing Artist Women in Science, Sci-Illustrate stories

Expressing myself graphically has always been a source of great satisfaction for me. With my work, I can provide many things to others in different positive ways, as well as get a lot in return, because in every goal achieved, in every process, there is a lot to learn.

About the series:

Not enough can be said about the amazing Women in Science who did and continue to do their part in moving the world forward.

Every month, through the artwork & words of the Sci-Illustrate team, we will bring to you profiles of women who touched our hearts (and brains) with their scientific works, and of many more who currently hold the flag high in their own fields!

— Dr. Radhika Patnala, Series Director



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