The structure of the ocean floor is extremely vast and irregular. In 1948, when Marie Tharp started working at the Lamont Geological Laboratory, not much was known about the seafloor, which was considered to be mostly flat and featureless.
Born into a cartographer family in Ypsilanti, Michigan, in the US, Tharp earned a bachelor’s degree in English and music from the Ohio University in 1943. She then completed her master’s in Geology from the University of Michigan. While working as a geologist for an Oklahoma-based oil company, she finished a degree in Mathematics from the University of Tulsa.
Tharp shifted to New York in 1948, and joined Columbia University’s geology department as research assistant. Eventually, when she and her colleague Bruce Heezen published the first map of the Atlantic Ocean in 1957, their drawings showed a seafloor covered with canyons, ridges, and mountains. Over the years, her maps went out to reveal the existence of mid-ocean ridges, a series of mountain ranges that span over 64,373.76 km around the globe. Through her maps, she demonstrated that a rift valley extended along the Mid-Atlantic ridge into the South Atlantic. Familiar valley structures were also found in the Indian Ocean, Arabian Sea, Red Sea, and the Gulf of Aden.
Also, her work of mapping the Hudson River’s underwater canyons provided early insights into comprehending underwater geological features and formations.
In 1977, the first complete world map of the ocean floors was published by Tharp and Heezen. The work aided in proving the theory of tectonic plates, which says that continents move over time. This discovery revolutionised our complete understanding on how the Earth works.
Tharp continued to work as faculty at Columbia University until 1983, after which she operated a map-distribution business in South Nyack during her retirement.
In 1997, the Library of Congress recognised Tharp as one of the four greatest cartographers of the 20th century. She also won the Lamont-Doherty Earth Observatory Heritage Award in 2001. Marie Tharp passed away due to cancer in 2006, at the age of 86.