Google is celebrating Marie Tharp today, an American geologist and oceanographic cartographer, on the anniversary of the day she was named one of the greatest cartographers of the 20th century.

In partnership with Bruce Heezen, she created the first scientific map of the Atlantic Ocean floor and discovered the Mid-Atlantic Ridge.

As a result of this discovery, the theories of plate tectonics and continental drift were accepted by the scientific community.

The Library of Congress recognized Tharp as one of the best cartographers of the 20th century on this day in 1998.

Her most well-known co-discovery is depicted in today’s animated doodle in her honor, along with the difficulties she had as a woman working in a male-dominated sector.

Who was Marie Tharp?

Marie was a renowned US geologist and oceanographic cartographer. On November 21, 1998, the Library of Congress named her one of the greatest cartographers of the 20th century.

Marie was born in Ypsilanti, Michigan, in 1920. Her father, who worked in the Department of Agriculture, introduced her to map-making.

She attended the University of Michigan and gained her Master’s degree in petroleum geology. Marie’s education in itself was a rare feat for a woman to achieve in the 1940s – but she didn’t stop there.

The Michigan native moved to New York City in 1948 to become the first woman to work at the Lamont Geological Observatory.

Tharp worked as a junior geologist for an oil company in Tulsa, Oklahoma. But as women at that time were not allowed to go on field trips she was confined to the office and found it unsatisfying.

She decided to enroll in the faculty of mathematics at the University of Tulsa and obtained her second BSc.

Eventually, she started working with Maurice Ewing, the founder of the Lamont Geological Observatory (now the Lamont–Doherty Earth Observatory) and became one of the first women to work there.

It was here that she met Bruce Heezen and in time she worked for Heezen exclusively, plotting the ocean floor using the newly invented sonar.

Because back then women were barred from working on ships she relied on the data Heezen and the rest of the research team collected.

With it, she was able to plot the height profiles of the Atlantic Ocean and it was then that she discovered the Mid-Atlantic Ridge.

There were skeptical. A ridge indicated continental drift, and this was an unpopular theory in geology at the time.

Tharp went back to the drawing board but still the results came through the same. She was able to work with a colleague, Howard Foster, who had been mapping earthquake activity in the same area, so they decided to overlay their maps. The maps matched. This convinced Bruce that the rift existed and so did continental drift.

Tharp and Heezen went on to publish papers and give lectures about their discovery, however, the scientific community remained unconvinced.

So, the sceptics decided to use the newly invented underwater camera to find out definitively. The video evidence confirmed the existence of the Mid-Atlantic Ridge and its ridge valley.

Tharp and Heezer published their first physiographic map of the North Atlantic in 1957. However, Tharp’s name does not appear on any of the major papers on plate tectonics that Heezen and others published between 1959 and 1963.

Nevertheless, she continued undeterred and identified that the rift valley extended along with the Mid-Atlantic Ridge into the South Atlantic.

She found a similar valley structure in the Indian Ocean, Arabian Sea, Red Sea, and Gulf of Aden, suggesting the presence of a global oceanic rift zone.

Although Tharp was later recognized and gained attribution for her work on the Mid-Atlantic Ridge, in 1956, it was Heezen who at the time received credit for the discovery that was made.

Tharp continued to serve on the faculty of Columbia University until 1983.

In retirement, she operated a map-distribution business in South Nyack, New York, and in 1995 she donated her map collection and notes to the Map and Geography Division of the Library of Congress.