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The woman who saw beneath oceans

by Donald Prothero, May 14 2014


Soundings: The Story of the Remarkable Woman Who Mapped the Ocean Floor by Hali Felt (Henry Holt & Co., New York, 2012)

For almost 70 years we have seen the large maps and globes showing the topography of the world’s oceans and continents, and taken them for granted. The map of the world’s land topography was a hard-won accomplishment made by generations of surveyors and cartographers, gradually improved and refined during the golden ages of exploration in the 1700s and 1800s. But before 1957, over 70% of the earth’s surface was simply unknown. Maps of the world’s oceans showed a few islands on a patch of solid blue, and not much else. Whatever was beneath the ocean’s surface was terra incognita. For the longest time, people thought that trilobites still roamed the seafloor, or that the entire seafloor was a flat featureless plain. Surprisingly, virtually all of the undersea world we now take for granted was mapped by one person! Even more remarkably, that person was a woman in an age where women had few opportunities in science. And sadly, despite the fact that she mapped more of our planet’s surface than any other person in history, her name is virtually unknown except to a few scientists. Fortunately, with the May 4 episode of “Cosmos” that just aired, her name is getting a bit more publicity.

Her name was Marie Tharp, and I was fortunate to meet her and her longtime scientific and romantic partner Bruce Heezen (pronounced HAY-zen) when I was still a graduate student at Lamont-Doherty Geological Observatory in the late 1970s. (Sadly, “Cosmos” mispronounced Heezen they way most people mispronounce it). Writer Hali Felt has produced a very enjoyable biography of this groundbreaking but underappreciated giant in the sciences of geology and geography. She was born in Ypsilanti, Michigan, on July 30, 1920, but she grew up in many different states, and followed a nearly rootless existence, because her father William made soil classification maps for many different state surveys. Always the new kid in town, she seldom made friends in school, but she was very bright and hardworking and did very well in her studies. As she got older, she spent a lot of time riding around with her father helping him in his work, so she learned about geology and natural history and mapping and surveying at a young age. She graduated from Ohio University in 1943 with majors in English and music and four minors. Then she got a master’s in geology at the University of Michigan at time when few women were allowed in geology, but wartime shortages of male students needed for the oil industry opened the door for her. For a while she worked at Stanolind Oil in Tulsa, Oklahoma, earning another degree in Mathematics at the University of Tulsa as she worked.

Marie Tharp in her later years with her famous maps and globes behind her.

Marie Tharp in her later years with her famous maps and globes behind her.

She soon got bored of menial drafting and mapping tasks assigned the women staffers and hoped for something bigger. On a whim, in 1948 she packed up her belongings and moved to New York City with no job offers or opportunities. She showed up at Schermerhorn Hall of Columbia University (where I took many classes when I was a Columbia grad student in geology), and asked around until she found herself in the basement, asking for a job in the lab of pioneering geophysicist and marine geologist Maurice Ewing (known as “Doc” Ewing to nearly everyone). At first she was expected to be a lowly secretary, but she persisted and soon earned the right to do drafting and mapping and illustrating reports for the busy Ewing lab, where marine geology was born in the United States. After a few years, Ewing moved his entire operation to the new Lamont Observatory up the Hudson River in Palisades, New York, where Columbia used the donation of the Lamont family mansion and grounds to found a new oceanographic and geologic research institute. There, working in the cramped attic of the Lamont mansion (the only building on the grounds then), she was accidentally assigned to be the draftsperson for marine geologist Bruce Heezen who was constantly at sea collecting data on Ewing’s ships.

Heezen was so busy with his data collection that he had almost no time to study the results, or plot or map them. In those days, women were not allowed aboard research ships, so Marie never got the opportunity to go to sea and take part in the data collection until late in her career. (She finally got her chance during a 1965 cruise, 17 years after she began her work). Instead, Marie took the long strips of paper from the echo sounder (which showed a profile of the depth of the ocean floor beneath the ship as it traveled), and turned it into a three-dimensional map that was accurately drafted based on the latitude and longitude data on the ship charts. In the days before computer drafting, this took tremendous aptitude not only in cartography, but also mathematical talents to determine precisely where the echo sounding profiles came from, converting scales from different maps, and to calculate true depth based on the seconds it takes for the echo to return to the ship. It also required a lot of geologic knowledge to make reasonable inferences and connections between features seen on the narrow lines of the profiles. From 1952 to 1957, she compiled the huge amount of data coming from the North Atlantic Ocean to make the first map of the floor of that ocean. Over the course of the rest of her career, she would do the same for every other ocean basin in the world. This culminated in the famous 1977 map of the entire ocean floor painted for National Geographic by Austrian landscape painter Heinrich Berann under the supervision of Heezen and Tharp.

A staged photo of a young Marie (late 1950s) with her map, and the depth profiles from which she got her map details shown on the left

A staged photo of a young Marie (late 1950s) with her map, and the depth profiles from which she got her map details shown on the left

Almost as soon as she completed her profiles across the North Atlantic, she provided the first accurate renderings of the Mid-Atlantic Ridge, a feature that had only been vaguely suggested by earlier scientists. As early as 1953, she could see that this ridge was longer than any mountain range on land, higher than the Himalayas, with a rift valley down the center of the ridge crest that was many times deeper and wider than the Grand Canyon. In addition, early seismic data showed that there was a zone of shallow-focus earthquakes in the middle of the rift valley, suggesting it was pulling apart. Both she and Heezen could see that there was no alternative but to explain this rift valley and ridge by seafloor spreading, but the rest of the world was not ready for that idea yet. Bruce and Doc Ewing wanted to explain it by an expanding earth model, but Marie was insistent that it required plate tectonics, an idea that was still 20 years away from widespread acceptance in the geological community. As Bruce and Marie’s North Atlantic and then South Atlantic maps were published, other geologists noticed the striking patterns of the mid-ocean ridges and their rifts, so that by 1963 sea-floor spreading was confirmed by other methods, such as the symmetry of the magnetic anomalies on each side of the ridge crest. In this regard, Marie’s maps provided some of the first solid evidence for plate tectonics, which was picked up by other male scientists who became more famous than she was for their later discoveries and insights.

Marie and her partner Bruce Heezen in the early 1960s, looking at their recently completed map of the Atlantic seafloor

Marie and her partner Bruce Heezen in the early 1960s, looking at their recently completed map of the Atlantic seafloor

Felt’s biography accurately captures not only the brilliance of Marie’s insights and the immense importance of her work, but it is also written in a lively style that imagines the events and scenes unfolding in Marie’s life, rather than just reciting the dry facts. Yet neither Felt nor any previous biographer could completely understand the relationship between Bruce and Marie. They gradually fell in love as they worked together more and more. But Marie was an independent woman and they never married—yet they lived together while maintaining separate houses through most of their lives. In fact, Bruce left most of his property to Marie when he unexpectedly died of a heart attack in 1977 at age 53, while diving in a deep-sea submarine. (I remember that moment vividly because everyone at Lamont was shocked when they heard the news). More importantly, Felt captures the way Marie struggled to earn the right to do work suited to her immense talents, and to gain recognition for her work in a world dominated by male scientists. Although she was no proto-feminist and didn’t like to rock the boat or attack men directly for their behavior, nonetheless she was smart and persistent and wore down her male colleagues until they gave her opportunities to shine, or to acknowledge her talents. Luckily for history, the task of mapping the ocean floor fell to the one woman with the right training and temperament and talents to do this immense job so successfully that no one has felt the need to redo her maps, even 50 years later with lots of new data.

After a dispute between Ewing and Heezen over credit and priority, Marie spent less and less time at Lamont, working out of her large home in Nyack, New York, instead. She formally retired in 1983, and set up her own map business at her house, where she made a living selling the maps she had made (and fortunately, owned the copyrights to as well). Late in life she received numerous honors from all the major geographic and geological societies and was honored by Woods Hole Oceanographic Institute, Lamont-Doherty Earth Observatory, and by the Library of Congress during the 100th anniversary of its map division (most of the letters and papers of Heezen and Tharp are in the Library of Congress). She died of cancer at age 86 in 2006.

As historian John Noble Wilford wrote in his 2000 book The Mapmakers: “Like other pioneering maps, the one by Heezen and Tharp is not complete and not always completely accurate. It is, nonetheless, one of the most remarkable achievements in modern cartography. It is the graphic summary of more than a century of oceanographic effort.”

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3 Responses to “The woman who saw beneath oceans”

  1. Mary Hannah says:

    Thanks for another wonderful article! Am looking forward to your guest appearance on Point of Inquiry. Your talks on You Tube are also highly recommended to anyone.

  2. Karen says:

    Maps and mapping have always interested me, so I’d be impressed with this woman even if she hadn’t had to struggle through all the sexism barriers. To have done both is remarkable.

  3. Scott the Aussie (in Devon!) says:

    Sounds a quite remrkable woman – I’d like to read that book. I wish she was more well known.