Today’s Google Doodle celebrates the life of Marie Tharp, an American geologist and oceanographic cartographer who helped prove the theories of continental drift. She co-published the first world map of the ocean floors. On this day in 1998, the Library of Congress named Tharp one of the greatest cartographers of the 20th century.
Marie Tharp was an only child born on July 30, 1920, in Ypsilanti, Michigan. Tharp’s father, who worked for the U.S. Department of Agriculture, gave her an early introduction to mapmaking. She attended the University of Michigan for her master’s degree in petroleum geology—this was particularly impressive given so few women worked in science during this period. She moved to New York City in 1948 and became the first woman to work at the Lamont Geological Observatory where she met geologist Bruce Heezen.
Heezen gathered ocean-depth data in the Atlantic Ocean, which Tharp used to create maps of the mysterious ocean floor. New findings from echo sounders (sonars used to find water depth) helped her discover the Mid-Atlantic Ridge. She brought these findings to Heezen, who infamously dismissed this as “girl talk”.
However, when they compared these V-shaped rifts with earthquake epicenter maps, Heezen could not ignore the facts. Plate tectonics and continental drift were no longer just theories—the seafloor was undoubtedly spreading. In 1957, Tharp and Heezen co-published the first map of the ocean floor in the North Atlantic. Twenty years later, National Geographic published the first world map of the entire ocean floor penned by Tharp and Heezen, titled “The World Ocean Floor.”
Marie Tharp donated her entire map collection to the Library of Congress in 1995. On the 100th anniversary celebration of its Geography and Map Division, the Library of Congress named her one of the most important cartographers in the 20th century. In 2001, the same observatory where she started her career awarded her with its first annual Lamont-Doherty Heritage Award.