Marie Tharp: Discoverer of the Rift Valley of the Mid-Atlantic Ridge and Inventor of Marine Cartography

By the latter half of the 20^thcentury the technologies behind SONAR, marine gravity, and marine magnetics had advanced to the point that the complexities of the ocean floor and beneath could be unraveled in unprecedented detail. Hence, scientists would finally be able to provide conclusive evidence for plate tectonics by way of plausible, proven physical mechanisms. But it took a young woman with an unusual background in geology, mathematics, and art to use that info to posit one of the most fundamental proofs of continental drift: a rift valley caused by the faulting of seafloor spreading. She did this while a researcher at Columbia University, in the lab of the iconic Maurice "Doc" Ewing, founder of the Lamont Geological Observatory. Along with geologist Bruce Heezen, she began the first systematic, comprehensive attempt to map the entire ocean floor. Heezen collected the data at sea, while Tharp developed a truly unique process for translating millions of these ocean-sounding records into a single drawing. During this process, she discovered the rift valley of the Mid-Atlantic Ridge, which Heezen at first discounted, holding incorrectly to his expanding Earth theory. Tharp's name was absent from the 1956 scientific paper that released this discovery to the world, and she was not given proper recognition for this and many other accomplishments until decades later. In 1968, she finally had the opportunity to go to sea, and performed the first ever shipboard processing and plotting of bathymetric data. During this time, Tharp and Heezen also formed a successful partnership with Austrian landscape painter Heinrich Berann to produce several panoramas of the ocean floor, leading to some of the most widely-recognized and beloved images in all of modern Earth science. Indeed, as her first, long-time employer, Doc Ewing, invented the field of marine geophysics, Tharp invented the field of marine cartography. Her story in words, data, and maps is a story that must continue be told for the future of science as well as the past. It is a remarkable testament to persistence, conviction, and courageous innovation.