The Woman Who Mapped The Sea Floor Was Dismissed For Years By Dumb Boy Scientists

Her groundbreaking scientific work was dismissed as “girl talk,” but that didn't stop Marie Tharp. In the 1940s and 1950s, Tharp earned her spot in a geology lab the hard way, at a time when men without degrees were handed research boats to captain. 

This is the story of the woman who mapped the sea floor. Tharp’s detailed work proved the existence of a rift valley in the middle of the Atlantic Ocean floor, providing critical proof for the “scientific heresy” of continental drift. The Marie Tharp map supported the new theory of plate tectonics, convincing doubters with a stunning depiction of the sea floor.

The female geologist who studied the sea floor faced barriers simply because she was a woman – but she persisted. Marie Tharp overcame dismissals, men taking credit for her work, and the “Pyrex Penis” to revolutionize geology and oceanography.

  • Before Tharp Began Her Research, The Dominant Idea Was That The Seafloor Was Muddy And Flat

    For centuries, no one knew what the bottom of the ocean looked like. Many assumed it was simply an empty plain of mud, "drab and flat." In the 1870s, a scientific voyage called the Challenger Expedition recorded the depth of the ocean by throwing a 200-pound weight overboard, letting it sink to the bottom, and hauling it back up to measure the rope length. It was a time-consuming way to gather scientific evidence, but it provided clues that the ocean floor might be an important mystery to unravel because of the data it returned.

    Everything changed in the 1950s with the groundbreaking scientific discovery made by Marie Tharp. Tharp, a trained geologist and mathematician, was dismissed because she was a woman, her findings waived off as “girl talk.” But Tharp’s astonishing scientific evidence about the seafloor revolutionized geology. It took years before Tharp truly received credit for her work – all because she was a woman working in a man’s field.

  • World War II Provided Opportunities For Women Like Tharp

    World War II Provided Opportunities For Women Like Tharp
    Photo: U.S. National Archives / Wikimedia Commons / Public Domain

    From an early age, Tharp was treated differently because she was a woman. She wanted to study literature at St. John’s College in Annapolis, Maryland, but women were not allowed to attend. Instead, she went to Ohio University.

    Tharp graduated in 1943, and she was quickly recruited to a geology master’s program at the University of Michigan due to the shortage of men in the earth sciences during World War II. But geology was a difficult field for women – women were still not allowed to join some professional societies, and they were largely barred from field studies, which are vital to geology research.

  • Men Were Handed Boats While Women Received Menial Jobs

    Men Were Handed Boats While Women Received Menial Jobs
    Video: YouTube

    Tharp was finally hired at Columbia University, boasting Master’s degrees in geology and mathematics, but the laboratory underutilized her skills. Her boss, Maurice "Doc" Ewing, didn't know what to make of a female geologist, so he assigned Tharp to the drafting table. Tharp undertook the tedious job of charting the data collected in the field by male research scientists.

    Ironically, Tharp’s future research partner, Bruce Heezen, met Doc Ewing as a junior in college and was immediately invited on a research expedition – and the next summer, before he even had a Bachelor’s degree, Heezen was given his own research ship!

  • The Theory Of Plate Tectonics Was Still Hotly Debated in Tharp’s Day

    The Theory Of Plate Tectonics Was Still Hotly Debated in Tharp’s Day
    Photo: Alfred Wegener / Wikimedia Commons / Public Domain

    Meteorology professor Alfred Wegener suggested the idea that the continents had once been part of a single, enormous landmass called Pangea in 1915. Wegener was correct, but he could not provide a convincing scientific explanation for his theory – aside from the similarity of the west coast of Africa and the east coast of South America and traces of fossils that cross continental divides – so his theory was rejected by geologists. He died feuding with the geological community.

    While Wegener claimed that continents cut through the Earth’s crust like icebreakers plowing an ice sheet, geologists dismissed his theory of “continental drift” as foolish. One geologist declared, “Wegener's hypothesis in general is of the footloose type, in that it takes considerable liberty with our globe, and is less bound by restrictions or tied down by awkward, ugly facts than most of its rival theories.”

    But Tharp’s research proved that the Earth’s plates did move, providing key evidence for the theory of plate tectonics. 

  • While The Men Went On Research Voyages, Tharp Was Left Behind In The Lab

    Navy regulations literally barred Tharp from traveling on research vessels with her colleagues. Ewing and Heezen set out on the Atlantis for two weeks every summer, taking depth measurements in the Atlantic Ocean. They brought along a deep-sea camera that Ewing called “The Pyrex Penis” because of its appearance.

    The voyages produced enormous amounts of data that had to be transformed into usable information. At her drafting table, Tharp plotted thousands of sounding numbers into a detailed seafloor map. She didn't have a calculator or a computer – everything was done by hand, working with pens, ink, and rulers.

  • Tharp Made An Amazing Discovery – A Valley On The Bottom Of The Atlantic Ocean

    Tharp Made An Amazing Discovery – A Valley On The Bottom Of The Atlantic Ocean
    Photo: National Oceanic and Atmospheric Administration / Wikimedia Commons / Public Domain

    As she plotted the data, Tharp uncovered a peculiar pattern. Most scientists at the time assumed the ocean floor was a vast, muddy plain. As Tharp herself related, they described the seafloor as "a flat, unchanging plain, a dumping ground slowly filled by sediments eroding from land." But Tharp noticed something unusual about the mountain range that Ewing's lab was studying at the bottom of the Atlantic Ocean. At the very ridge of the range, Tharp found a deep valley – so deep that she double checked her calculations.

    The valley upended scientific knowledge, providing support for the largely discredited theory of continental drift. Tharp had discovered evidence of seafloor spreading – the creation of new seafloor at a seam between tectonic plates.