Marie Tharp

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Marie Tharp
Marie Tharp working with fathometer record (cropped).jpg
Marie Tharp in 1968
Born(1920-07-30)July 30, 1920
DiedAugust 23, 2006(2006-08-23) (aged 86)
Alma materOhio University
University of Michigan
University of Tulsa
Known forSeafloor topography
Scientific career
FieldsGeology, Oceanography
InstitutionsLamont–Doherty Earth Observatory Columbia University
Bathymetric globe produced by Marie Tharp and Bruce Heezen
Manuscript map created by Tharp and Heezen depicting the early developments of the understanding of the ocean's bottom (1957)

Marie Tharp (July 30, 1920 – August 23, 2006) was an American geologist and oceanographic cartographer. In the 1950s, she collaborated with geologist Bruce Heezen to produce the first scientific map of the Atlantic Ocean floor.[1] Her cartography revealed a more detailed topography and multi-dimensional geographical landscape of the ocean bottom.[2]

Tharp's discovery of the Mid-Atlantic Ridge caused a paradigm shift in earth science that led to acceptance of the theories of plate tectonics and continental drift.[3][4][5]

Early life and education[edit]

Marie Tharp was born on July 30, 1920, in Ypsilanti, Michigan, the only child of Bertha Louise Tharp, a German and Latin teacher, and William Edgar Tharp, a soil surveyor for the United States Department of Agriculture.[6] She often accompanied her father on his field work, which gave her an early introduction to mapmaking. Despite this, she had no interest in pursuing a career in field work as during that time this was understood to be men's work.[citation needed]

Due to the nature of William Tharp's work, the family moved constantly until he retired in 1931. At that point Marie had attended over 17[7] public schools in Alabama, Iowa, Michigan and Indiana, which made it difficult for her to establish friendships.[6] Her mother, who died when Marie was 15,[8] was her closest female acquaintance.[6] A full school year in Florence, Alabama, was particularly influential for her. There she attended a class called Current Science, in which she learned about contemporary scientists and their research projects. In addition, she undertook school field trips on weekends to study trees and rocks.[8]

After her father's retirement, Marie Tharp moved to a farm in Bellefontaine, Ohio, where she graduated from the local high school.[2] She took some gap years between high school and college to work on her family's farm.[7] She entered the Ohio University in 1939, where she "changed her major every semester."[7]

Tharp graduated from Ohio University in 1943 with bachelor's degrees in English and music and four minors.

After the Japanese attack on Pearl Harbor, many young men dropped out of schools and universities to join the armed forces.[9] During World War II, more women were recruited into professions like petroleum geology, normally restricted to men."With classrooms empty of men during the war years, Michigan—which had never allowed women into its geology program—was trying to fill seats,"[2] though less than 4% of all earth sciences doctorates at the time were obtained by women.[10] Having taken a geology class at Ohio, Tharp attended the University of Michigan at Ann Arbor's petroleum geology program, where she completed a master's degree in 1944.[11][2]

After graduating, Tharp began work as a junior geologist at the Stanolind Oil company in Tulsa, Oklahoma, but discovered that the company did not permit women to do nor attend field work. Tharp was only permitted to coordinate maps and data for male colleagues' trips.[2][9] While still working as a geologist for the Stanolind Oil company, Tharp enrolled in the faculty of mathematics at the University of Tulsa, obtaining her second BSc.[9]


By 1948, Tharp had spent four years in Tulsa and was looking for her next career step. She moved to New York City and initially sought work at the American Museum of Natural History, but after learning how time-consuming paleontological research was, she looked for positions at Columbia University.[12] She eventually found drafting work with Maurice Ewing, the founder of the Lamont Geological Observatory (now the Lamont–Doherty Earth Observatory). Curiously, when interviewed for the job, Tharp did not mention she had a master's degree in geology.[13] Tharp was one of the first women to work at the Lamont Geological Observatory.

While there, she met Bruce Heezen, and in early work together they used photographic data to locate downed military aircraft from World War II.[14] Eventually she worked for Heezen exclusively, plotting the ocean floor.[12] Tharp was employed and continuously promoted from 1952 to 1968, when her position was cut and moved to grant-funded status due to lab politics involving Heezen[clarification needed] (she remained in a grant-funded position until Heezen's death in 1977). Because of the Cold War, the U.S. government forbade seafloor maps to be published, for fear that Soviet submarines could use them.[9]

For the first 18 years of their collaboration, Heezen collected bathymetric data aboard the research ship Vema, while Tharp drew maps from that data, since women were barred from working on ships at the time. She was later able to join a 1968 data-collection expedition on the USNS Kane.[15] She independently used data collected from the Woods Hole Oceanographic Institution's research ship Atlantis, and seismographic data from undersea earthquakes. Her work with Heezen represented the first systematic attempt to map the entire ocean floor.

As early as the mid-19th century, a submarine mountain range in the Atlantic had been roughly outlined by John Murray and Johan Hjort. Marie Tharp also discovered the rift valley on her more precise graphical representations of the Mid-Atlantic Ridge, which were based on new measurement data obtained with the echo sounder. It took her a year to convince Bruce Heezen of this. Later, she also mapped the other mid-ocean ridges.[16][17]

Continental drift theory[edit]

Don Blomquist and Marie Tharp at the drafting table; maps of the Mid-Atlantic ridge can be seen

Before the early 1950s, scientists knew very little about the structure of the ocean floor. Though studying geology on land was cheaper and easier, the overall structure of the earth could not be understood without knowledge of the structure and evolution of the seafloor.

In 1952, Tharp painstakingly aligned sounding profiles from Atlantis, acquired during 1946–1952, and one profile from the naval ship Stewart acquired during 1921. She created a total of approximately six profiles stretching west-to-east across the North Atlantic. From these profiles, she was able to examine the bathymetry of the northern sections of the Mid-Atlantic Ridge. Tharp identified an aligned, v-shaped structure running continuously through the axis of the ridge and believed that it might be a rift valley[12][18] formed by the oceanic surface being pulled apart.[12] Heezen was initially unconvinced as the idea would have supported continental drift, then a controversial theory. At the time many scientists, including Heezen, believed that continental drift was impossible. Instead, for a time, he favored the Expanding Earth hypothesis,[19][20] (now infamously) dismissing her explanation as "girl talk".[21]

Heezen soon hired Howard Foster to plot the location of earthquake epicenters in the oceans for a project relating large-scale turbidity currents to undersea earthquakes. The creation of this earthquake epicenter map proved to be a useful secondary dataset for examining the bathymetry of the Mid-Atlantic Ridge. When Foster's map of earthquake epicenters was overlaid with Tharp's profile of the Mid-Atlantic Ridge it became clear that the location of these earthquakes aligned with Tharp's rift valley. After putting together these two datasets, Tharp became convinced that a rift valley did in fact exist within the crest of the Mid-Atlantic Ridge.[12] It was only after seeing that the location of earthquake epicenters aligned with Tharp's rift valley that Heezen accepted her hypothesis and turned to the alternative theories of plate tectonics and continental drift.[22][23]

Painting of the Mid-Ocean Ridge by Heinrich Berann (1977) based on the scientific profiles of Marie Tharp and Bruce Heezen
Marty Weiss, Al Ballard, and Marie Tharp conversing on the maiden voyage of the USNS Kane, c. 1968

Tharp and Heezen published their first physiographic map of the North Atlantic in 1957.[12] Still, Tharp's name does not appear on any of the major papers on plate tectonics that Heezen and others published between 1959 and 1963. Tharp continued working with graduate student assistants to further map the extent of the central rift valley. Tharp demonstrated that the rift valley extended along with the Mid-Atlantic Ridge into the South Atlantic,[12] and found a similar valley structure in the Indian Ocean, Arabian Sea, Red Sea, and Gulf of Aden, suggesting the presence of a global oceanic rift zone.[24] Subsequently, in collaboration with the Austrian landscape painter Heinrich Berann, Tharp and Heezen realized their map of the entire ocean floor, which was published in 1977 by National Geographic under the title of The World Ocean Floor.[9] Although Tharp was later recognized and credited for her work on the Mid-Atlantic Ridge, it was Heezen who, at the time in 1956, put out and received credit for the discovery that was made.

Retirement and death[edit]

After Heezen's death, Tharp continued to serve on the faculty of Columbia University until 1983, after which she operated a map-distribution business in South Nyack during her retirement.[25] Tharp donated her map collection and notes to the Map and Geography Division of the Library of Congress in 1995.[26] In 1997, Tharp received double honors from the Library of Congress, which named her one of the four greatest cartographers of the 20th century and included her work in an exhibit in the 100th-anniversary celebration of its Geography and Map Division.[27] In 2001, Tharp was awarded the first annual Lamont–Doherty Heritage Award at her home institution for her life's work as a pioneer of oceanography.[3] Tharp died of cancer in Nyack, New York, on August 23, 2006, at the age of 86.[28]

Personal life[edit]

In 1948, she married David Flanagan and moved with him to New York. They divorced in 1952.[29]

Awards and honors[edit]

Like many scientists, Marie Tharp was recognized mainly later in life. Her awards include:


Tharp was recognized in 1997 by the Library of Congress as one of the four greatest cartographers of the 20th century.[31] The position of Marie Tharp Lamont Research Professor was created in her honor.[32]

Marie Tharp Fellowship[edit]

Created by Lamont in 2004, the Marie Tharp Fellowship is a competitive academic visiting fellowship awarded to women to work with researchers at the Earth Institute of Columbia University.[33][34] Women who are accepted are given the opportunity to work with faculty, research staff, postdoctoral researchers and graduate students and in the duration of 3 months, they are awarded up to $30,000 as financial aid.[35][25]

Posthumous recognition[edit]

Google Earth included the Marie Tharp Historical Map layer in 2009, allowing people to view Tharp's ocean map using the Google Earth interface.[36] She is the subject of the 2013 biography by Hali Felt entitled Soundings: The Story of the Remarkable Woman Who Mapped the Ocean Floor, which was cited by the New York Times for its standing as an "eloquent testament both to Tharp's importance and to Felt's powers of imagination."[37]

She was animated in "The Lost Worlds of Planet Earth", the ninth episode of Neil deGrasse Tyson’s Cosmos: A Spacetime Odyssey, and voiced by actress Amanda Seyfried. The episode depicts her discovery of the Mid-Atlantic Ridge and subsequently later in the episode deGrasse Tyson recognized Tharp not only as an influential scientist who happens to be a woman but also as one who should be recognized as a scientist who overcame sexism to contribute to her field.[38] Her life story is told in three children's books, Solving the Puzzle Under the Sea: Marie Tharp Maps the Ocean Floor, by Robert Burleigh and illustrated by Raúl Colón, Ocean Speaks: How Marie Tharp Revealed the Ocean's Biggest Secret by Jess Keatting and illustrated by Katie Hickey and in 2020 MacMillan published Marie's Ocean: Marie Tharp Maps the Mountains under the Sea written and illustrated by Josie James. This picture book of Tharp's life was honored as a National Science Teaching Association Best STEM Book of 2021 and a National Council for the Social Studies 2021 Notable Social Studies Trade Book for Young Readers.

In 2015 the International Astronomical Union named the Tharp Moon crater in her honor.

In 2022 the non-profit Ocean Research Project named their 72ft research schooner after her.[39]

On November 21, 2022, Google honored Tharp by releasing a Google Doodle which included narration, mini games, and animations, telling the story of Tharp's discovery of continental drift and provided historical context for her work.[40]

Selected publications[edit]

  • Tharp, Marie; Heezen, Bruce C.; Ewing, Maurice (1959). The floors of the oceans: I. The North Atlantic. Vol. 65. Geological Society of America. doi:10.1130/SPE65-p1.
  • Heezen, B C; Bunce, Elizabeth T; Hersey, J B; Tharp, Marie (1964). "Chain and Romanche fracture zones". Deep-Sea Research and Oceanographic Abstracts. 11 (1): 11–33. Bibcode:1964DSRA...11...11H. doi:10.1016/0011-7471(64)91079-4.
  • Heezen, B C; Tharp, Marie (1965). "Tectonic fabric of the atlantic and indian oceans and continental drift". Philosophical Transactions of the Royal Society of London A. 258 (1088): 90–106. Bibcode:1965RSPTA.258...90H. doi:10.1098/rsta.1965.0024. S2CID 121476006.
  • Tharp, Marie; Friedman, Gerald M (2002). "Mapping the world ocean floor". Northeastern Geology and Environmental Sciences. 24 (2): 142–149..


  1. ^ O'Connell, Suzanne (August 8, 2020). "Marie Tharp's maps revolutionized our knowledge of the seafloor". The Washington Post.
  2. ^ a b c d e "Marie Tharp |". Retrieved February 7, 2019.
  3. ^ a b Lamont–Doherty Earth Observatory Bestows Heritage Award on Marie Tharp, Pioneer of Modern Oceanography, Published Jul 10, 2001, Retrieved Oct 12, 2014
  4. ^ Erin Blakemore: Seeing Is Believing: How Marie Tharp Changed Geology Forever. In: Smithsonian Magazine, 30. August 2016.
  5. ^ Earth Institute: Marie Tharp’s Adventures in Mapping the Seafloor, In Her Own Words. Columbia Climate School, 24. Juli 2020.
  6. ^ a b c Higgs, Bettie Matheson (July 13, 2020). "Understanding the Earth: the contribution of Marie Tharp". Geological Society, London, Special Publications. 506: SP506–2019–248. doi:10.1144/SP506-2019-248. hdl:10468/11315. ISSN 0305-8719. S2CID 225540884.
  7. ^ a b c "Marie Tharp – Ages of Exploration". Retrieved February 7, 2019.
  8. ^ a b Felt, Hali (June 2017). "Marie Tharp – Plate Tectonics Pioneer" (PDF). Geological Society of America.
  9. ^ a b c d e Yount, L. (2006). Modern Marine Science: Exploring the Deep. Facts On File, Incorporated. ISBN 9781604130669.
  10. ^ Blakemore, Erin (August 30, 2016). "Seeing Is Believing: How Marie Tharp Changed Geology Forever". Smithsonian.
  11. ^ Barton, Cathy (2002). "Marie Tharp, oceanographic cartographer, and her contributions to the revolution in the Earth sciences". Geological Society, London, Special Publications. 192 (1): 215–228. Bibcode:2002GSLSP.192..215B. CiteSeerX doi:10.1144/gsl.sp.2002.192.01.11. S2CID 131340403.
  12. ^ a b c d e f g Tharp, Marie (December 12, 2006). "Marie Tharp biography". Woods Hole Oceanographic Institution. Archived from the original on January 8, 2007. Retrieved June 2, 2008.
  13. ^ A Student's Guide to Earth Science, Volume 2. Greenwood Publishing Group. 2004. ISBN 031332901X.
  14. ^ Evans, R. (November 2002). "Plumbing Depths to Reach New Heights". Library of Congress. Retrieved June 2, 2008.
  15. ^ Woodward, William (2017). "New Collection of USNS Kane Maiden Scientific Voyage Photographs". AIP History Newsletter. 49 (1): 8–9 – via {{cite journal}}: External link in |via= (help)
  16. ^ Betsy Mason: Marie Tharp's groundbreaking maps brought the seafloor to the world. In: [Science News], 13 January 2021.
  17. ^ Sabine Höhler: A Sound Survey: The Technological Perception of Ocean Depth, 1850–1930. In: Transforming Spaces. The Topological Turn in Technology Studies.
  18. ^ North, Gary W. (January 1, 2010). "Marie Tharp: The lady who showed us the ocean floors". Physics and Chemistry of the Earth, Parts A/B/C. 35 (15–18): 881–886. Bibcode:2010PCE....35..881N. doi:10.1016/j.pce.2010.05.007. ISSN 1474-7065.
  19. ^ Barton, C. (2002). "Marie Tharp, oceanographic cartographer, and her contributions to the revolution in the Earth sciences". Geological Society, London, Special Publications. 192 (1): 215–228. Bibcode:2002GSLSP.192..215B. CiteSeerX doi:10.1144/GSL.SP.2002.192.01.11. S2CID 131340403.
  20. ^ Doel, R.E.; Levin, T.J.; Marker, M.K. (2006). "Extending modern cartography to the ocean depths: military patronage, Cold War priorities, and the Heezen-Tharp mapping project, 1952–1959". Journal of Historical Geography. 32 (3): 605–626. doi:10.1016/j.jhg.2005.10.011.
  21. ^ Tharp, Marie (1999). "Chapter 2: Connect the Dots: Mapping the Seafloor and Discovering the Mid-ocean Ridge". In Lippsett, Laurence (ed.). Lamont–Doherty Earth Observatory of Columbia, Twelve Perspectives on the First Fifty Years 1949–1999. Lamont–Doherty Earth Observatory of Columbia University, Palisades, NY. OCLC 43636190.
  22. ^ Felt, Hali (2017). "ROCK STARS: Marie Tharp – Plate Tectonics Pioneer". GSA Today. 27: 32–33.
  23. ^ Wills, Matthew (October 8, 2016). "The Mother of Ocean Floor Cartography". JSTOR. Retrieved October 14, 2016. While working with the North Atlantic data, she noted what must have been a rift between high undersea mountains. This suggested earthquake activity, which then [was] only associated with [the] fringe theory of continental drift. Heezen infamously dismissed his assistant's idea as "girl talk." But she was right, and her thinking helped to vindicate Alfred Wegener's 1912 theory of moving continents. Yet Tharp's name isn't on any of the key papers that Heezen and others published about plate tectonics between 1959–1963, which brought this once-controversial idea to the mainstream of earth sciences.
  24. ^ Lawrence, David M. (2002). Upheaval from the abyss : ocean floor mapping and the Earth science revolution. Rutgers University Press. ISBN 978-0813530284. OCLC 605755403.
  25. ^ a b "Marie Tharp | Earth 520: Plate Tectonics and People: Foundations of Solid Earth Science".
  26. ^ "Primary Sources in Science Classrooms: Mapping the Ocean Floor, Marie Tharp, and Making Arguments from Evidence (Part 1) | Teaching with the Library of Congress". October 8, 2015. Retrieved October 29, 2015.
  27. ^ Jarvis, Brooke (December 9, 2014). "How One Woman's Discovery Shook the Foundations of Geology".
  28. ^ Fox, Margalit (August 26, 2006). "Marie Tharp, Oceanographic Cartographer, Dies at 86". New York Times. Retrieved April 9, 2012.
  29. ^ Felt, Hali (2012). Soundings: The Story of the Remarkable Woman Who Mapped The Ocean Floor. Henry Holt.
  30. ^ "Marie Tharp". Physics Today. July 30, 2018. doi:10.1063/PT.6.6.20180730a. S2CID 240374077.
  31. ^ "Join Us in Celebrating #MarieTharp100". State of the Planet. July 23, 2020. Retrieved September 13, 2020.
  32. ^ Aronsohn, Marie Denoia (July 27, 2020). "Lamont's Marie Tharp: She Drew the Maps That Shook the World". State of the Planet. Retrieved September 13, 2020.
  33. ^ "Marie Tharp Fellowship Information" (PDF). Columbia University. January 23, 2012. Archived from the original (PDF) on December 20, 2012.
  34. ^ "The Marie Tharp Fellowship". The Earth Institute, Columbia University. Archived from the original on July 8, 2018. Retrieved August 22, 2016.
  35. ^ "Applications Now Being Accepted for Marie Tharp Visiting Fellowship". The Earth Institute Columbia University. January 20, 2010. Archived from the original on June 13, 2010. Retrieved February 6, 2019.
  36. ^ "Google Earth drops into the oceans". Guardian News. February 2, 2009. Retrieved September 13, 2020.
  37. ^ Washburn, Michael (January 25, 2013). "Floating Ideas: Soundings, About Marie Tharp, by Hali Felt". New York Times. Retrieved September 13, 2020.
  38. ^ Algar, Jim (May 7, 2014). "Cosmos Episode 9 'The Lost Worlds of Planet Earth': Amanda Seyfried walks us through Earth's early past". Tech Times. Retrieved September 13, 2020.
  39. ^ "The RV Marie Tharp: Ocean Research Project's steel polar expedition schooner". Ocean Research Project. Retrieved May 11, 2022.
  40. ^ "Celebrating Marie Tharp". Retrieved November 20, 2022.

Further reading[edit]