The early ideas about plate tectonics were still quite controversial & unpopular. Heezen dismissed this as “girl talk” - though really a vital piece of #PlateTectonics puzzle. Tharp believed rift was real though she hadn’t convinced Heezen. In 1952, they began working on physiographic maps,
which really gave a sense of the geology, & were not US Navy classified, so they could publish. A 2nd project involved plotting earthquakes, & Heezen insisted they work at same scale. Heezen noticed that ocean earthquake epicentre data also formed long lines - in fact, when one map was placed above
the other on a light table the earthquakes formed near continous lines along the Mid-Atlantic ridge right where Tharp had indicated a rift valley. Using earthquake data to extrapolate & plot the rift position they found that the rift extended landward into the Rift Valley of East Africa. Heezen
was convinced. They had discovered a worldwide mid-ocean ridge system, 10,000s of km long. Tharp was able to mine existing data to show the Mid-Atlantic Ridge extended to S Atlantic & found similar features in other oceans which lined up with epicentres.
Ewing & Heezen announced their findings in 1956. In 1957 Tharp & Heezen published their N Atlantic physiographic map. #sciart #printmaking #womenInSTEM #linocut