Forbes has a story about Marie Tharp and her contributions to geology.   During the International Geophysical Year 1857, Marie Tharp noticed a series of valleys and ridges in the middle Atlantic Ocean.  These “lines” are essentially the mark of the sea floor spreading at the tectonic plate boundary, although at the time, the concept of plate tectonics was unknown.  This evidence was proof that the continents moved… a basic key to understanding the history of life on our planet!

At the time, the U.S. Navy was interested in mapping the seafloor, believed to be of strategic importance for future submarine warfare. Marie started a prolific collaboration with geologist Bruce Charles Heezen, a specialist for seismic and topographic data obtained from the seafloor. As a woman, Marie was not allowed aboard the research ships. Instead, she interpreted and visualized the collected data in her laboratory, producing large hand-drawn maps of the seafloor.

By interpolating and plotting the echo soundings of the seafloor collected from the research ships and after months of very detailed and careful work, in 1957 Marie Tharp noted a series of valleys and ridges in the midst of the Atlantic Ocean.

The existence of a single ridge under the Atlantic Ocean was discovered during the expedition of HMS Challenger in 1872, taking depth measurements across the ocean. In 1925, it was confirmed by sonar that the ridge of unknown origin extends around the Cape of Good Hope into the Indian Ocean, making it one of the largest mountain ranges on Earth. Marie Tharp suggested that the mid-Atlantic ridge was in fact a series of rift valleys, running parallel along a central axis where new oceanic crust is formed, pushing apart blocks of older seafloor, forming the ridge topography. Her idea rejected as “girl talk” at first. Even Heezen stubbornly refused to accept this explanation for the ridge, claiming that it sounded like the “debunked” continental drift hypothesis as proposed by Alfred Wegener in 1912.

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Unlike Alfred Wegener, who died in 1930, Marie Tharp lived long enough to see her research become a fundamental part of modern geology.

“Not too many people can say this about their lives: The whole world was spread out before me (or at least, the 70 percent of it covered by oceans). I had a blank canvas to fill with extraordinary possibilities, a fascinating jigsaw puzzle to piece together: mapping the world’s vast hidden seafloor. It was a once-in-a-lifetime—a once-in-the-history-of-the-world—opportunity for anyone, but especially for a woman in the 1940s. The nature of the times, the state of the science, and events large and small, logical and illogical, combined to make it all happen.”