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42-742: The continuous observations are measured by an array of instruments along 26°N. This monitoring array directly measures the transport of the Gulf Stream in the Florida Strait using an undersea cable and a moored array measures bottom pressure and water column density (including temperature and salinity) at the western and eastern boundary and on either side of the Mid-Atlantic Ridge (MAR) . Absolute transports including barotropic circulation are monitored using precision bottom pressure gauges. "Dynamic height" moorings are used to estimate

84-488: A class called Current Science , where she learned about contemporary scientists and their research projects. In addition, she undertook school field trips on weekends to study trees and rocks. After her father's retirement, Marie Tharp moved to a farm in Bellefontaine, Ohio , where she graduated from the local high school. She spent gap years between high school and college working on her family's farm. She entered

126-407: A flow of ocean water of 10 cubic meters per second) as compared to expected measurement errors of 2.7 Sv. In another study also utilizing observations from March 2004 to March 2005, Cunningham et al. (2007) reported a year-long average MOC of 18.7 ± 5.6 Sv with a large variability ranging from 4.4 to 35.3 Sv within the course of a year. Johns et al. (2009) concluded that the meridional heat transport

168-701: A junction with the Gakkel Ridge (Mid-Arctic Ridge) northeast of Greenland southward to the Bouvet triple junction in the South Atlantic. Although the Mid-Atlantic Ridge is mostly an underwater feature, portions of it have enough elevation to extend above sea level, for example in Iceland . The ridge has an average spreading rate of about 2.5 centimetres (1 in) per year. A ridge under

210-750: A junior geologist at the Stanolind Oil company in Tulsa, Oklahoma , but discovered that the company did not permit women to do nor attend fieldwork. The company only permitted Tharp to coordinate maps and data for male colleagues' trips. 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. By 1948, Tharp had spent four years in Tulsa and

252-465: A more realistic style, and published their first physiographic map of the North Atlantic in 1957. Tharp's name did 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

294-572: A rift valley existed within the crest of the Mid-Atlantic Ridge. 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. Because of the Cold War , the U.S. government forbade topographic seafloor maps to be published for fear that Soviet submarines could use them. To circumvent that restriction, Tharp and Heezen decided to draw their maps in

336-539: A year to convince Bruce Heezen of this. Later, she also mapped the other mid-ocean ridges . Before the early 1950s, scientists knew very little about the ocean floor structure. 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

378-728: Is a mid-ocean ridge (a divergent or constructive plate boundary ) located along the floor of the Atlantic Ocean , and part of the longest mountain range in the world . In the North Atlantic, the ridge separates the North American from the Eurasian plate and the African plate , north and south of the Azores triple junction . In the South Atlantic, it separates the African and South American plates. The ridge extends from

420-702: 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." 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

462-625: The Earth Institute of Columbia University . 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. Google Earth included the Marie Tharp Historical Map layer in 2009, allowing people to view Tharp's ocean map using the Google Earth interface. She

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504-613: 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. 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 providing historical context for her work. On March 8, 2023 ( International Women's Day ),

546-606: The Mississippi River , Amazon River and Niger River ). The Fundy Basin on the Atlantic coast of North America between New Brunswick and Nova Scotia in Canada is evidence of the ancestral Mid-Atlantic Ridge. Marie Tharp 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

588-709: The Tjörnes fracture zone connects Iceland to the Kolbeinsey Ridge . The ridge sits atop a geologic feature known as the Mid-Atlantic Rise , which is a progressive bulge that runs the length of the Atlantic Ocean, with the ridge resting on the highest point of this linear bulge. This bulge is thought to be caused by upward convective forces in the asthenosphere pushing the oceanic crust and lithosphere . This divergent boundary first formed in

630-520: The Triassic period, when a series of three-armed grabens coalesced on the supercontinent Pangaea to form the ridge. Usually, only two arms of any given three-armed graben become part of a divergent plate boundary. The failed arms are called aulacogens , and the aulacogens of the Mid-Atlantic Ridge eventually became many of the large river valleys seen along the Americas and Africa (including

672-405: The epicenter of many earthquakes . Ewing, Heezen and Tharp discovered that the ridge is part of a 40,000-km (25,000 mile) long essentially continuous system of mid-ocean ridges on the floors of all the Earth's oceans. The discovery of this worldwide ridge system led to the theory of seafloor spreading and general acceptance of Alfred Wegener 's theory of continental drift and expansion in

714-588: The Map and Geography Division of the Library of Congress in 1995. 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. Tharp died of cancer in Nyack, New York , on August 23, 2006, at the age of 86. In 1948, she married David Flanagan and moved with him to New York. They divorced in 1952. Like many scientists, Marie Tharp

756-536: The Mid-Atlantic Ridge into the South Atlantic, 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. 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

798-558: The Mid-Atlantic Ridge, from north to south, with their respective highest peaks and location, are: Northern Hemisphere (North Atlantic Ridge) : Southern Hemisphere (South Atlantic Ridge) : The submarine section of the Mid-Atlantic Ridge close to southwest Iceland is known as the Reykjanes Ridge . The Mid-Atlantic Ridge runs through Iceland where the ridge is also known as the Neovolcanic Zone . In northern Iceland

840-589: The Mid-Atlantic Ridge. 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. 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

882-664: 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

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924-641: The Ohio University in 1939, where she "changed her major every semester." 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 left schools and universities to join the armed forces. During World War II , more women were recruited into professions like petroleum geology , normally restricted to men. "With classrooms empty of men during

966-644: 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 . 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

1008-479: The first scientific map of the Atlantic Ocean floor. Her cartography revealed a more detailed topography and multi-dimensional geographical landscape of the ocean bottom. Tharp's discovery of the Mid-Atlantic Ridge caused a paradigm shift in earth science that led to the acceptance of the theories of plate tectonics and continental drift . Marie Tharp was born on July 30, 1920, in Ypsilanti, Michigan ,

1050-408: 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

1092-552: The future location for a transatlantic telegraph cable . The existence of such a ridge was confirmed by sonar in 1925 and was found to extend around Cape Agulhas into the Indian Ocean by the German Meteor expedition . In the 1950s, mapping of the Earth's ocean floors by Marie Tharp , Bruce Heezen , Maurice Ewing , and others revealed that the Mid-Atlantic Ridge had a strange bathymetry of valleys and ridges, with its central valley being seismologically active and

1134-580: The geostrophic and direct current observations. RAPID-MOCHA is funded by the National Environmental Research Council (NERC) and the National Science Foundation (NSF). Kanzow and colleagues (2007) demonstrated the effective of the array and reported that the sum of the transports into the North Atlantic from March 2004 to March 2005 varies with root-mean-square value of only 3.4 Sv (where 1 Sv =

1176-703: The job, Tharp did not mention she had a master's degree in geology. 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. Eventually she worked for Heezen exclusively, plotting the ocean floor. In 1964, due to a professional disagreement between Ewing and Heezen, Ewing cut off Heezen's access to Lamont data, and then fired Tharp. She continued to work on mapping projects from her home, being paid by Heezen through navy contracts. For

1218-471: The modified form of plate tectonics . The ridge is central to the breakup of the hypothetical supercontinent of Pangaea that began some 180 million years ago. The Mid-Atlantic Ridge includes a deep rift valley that runs along the axis of the ridge for nearly its entire length. This rift marks the actual boundary between adjacent tectonic plates, where magma from the mantle reaches the seafloor, erupting as lava and producing new crustal material for

1260-536: The nature of William Tharp's work, the family constantly moved until he retired in 1931. At that point, Marie had attended over 17 public schools in Alabama , Iowa , Michigan and Indiana , which made it difficult for her to establish friendships. Her mother, who died when Marie was 15, was her closest female acquaintance. A full school year in Florence, Alabama , was particularly influential for her. She attended

1302-436: The naval ship Stewart acquired in 1921. She created approximately six profiles stretching west to east across the North Atlantic. From these profiles, she examined 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 formed by the oceanic surface being pulled apart. Heezen

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1344-462: The northern Atlantic Ocean was first inferred by Matthew Fontaine Maury in 1853, based on soundings by the USS Dolphin . The existence of the ridge and its extension into the South Atlantic was confirmed during the expedition of HMS Challenger in 1872. A team of scientists on board, led by Charles Wyville Thomson , discovered a large rise in the middle of the Atlantic while investigating

1386-499: 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

1428-483: 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 . She often accompanied her father on his fieldwork, which gave her an early introduction to mapmaking . Despite this, she had no interest in pursuing a career in fieldwork as, during that time, this was understood to be men's work. Due to

1470-764: The plates. Near the equator , the Mid-Atlantic Ridge is divided into the North Atlantic Ridge and the South Atlantic Ridge by the Romanche Trench , a narrow submarine trench with a maximum depth of 7,758 m (25,453 ft), one of the deepest locations of the Atlantic Ocean. This trench, however, is not regarded as the boundary between the North and South American plates, nor the Eurasian and African plates. The islands on or near

1512-468: The spatially average geostropic velocity profile and associated transports over relatively wide mooring separations. The dynamic height moorings requires measurements on both sides of the current field only, rather both the horizontal and vertical structure of the current field to be sufficiently well resolved to estimate transports. The basin-wide MOC strength and vertical structure are estimated via Ekman transports by satellite scatterometer measurements and

1554-531: The title of The World Ocean Floor . 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. 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. Tharp donated her map collection and notes to

1596-413: The war years, Michigan—which had never allowed women into its geology program—was trying to fill seats," though less than 4% of all earth sciences doctorates at the time were obtained by women. 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. After graduating, Tharp began work as

1638-493: Was highly correlated with changes in the strength of the MOC with the circulation accounting for nearly 90% of the total heat transport and the remainder contained in a quasi-stationary gyre pattern with little net contribution by mesoscale eddies . The average annual mean meridional heat transport from 2004-2007 was reported by Johns et al. (2009) to be 1.33 ± 0.14 petawatts (PW). Mid-Atlantic Ridge The Mid-Atlantic Ridge

1680-481: Was initially unconvinced as the idea would have supported continental drift , then a controversial theory. Many scientists, including Heezen, believed that continental drift was impossible at the time. Instead, for a time, he favored the Expanding Earth hypothesis, (now infamously) dismissing her explanation as "girl talk". Heezen soon hired Howard Foster to plot the location of earthquake epicenters in

1722-586: Was looking for her next career step. She moved to New York City and initially sought work at the American Museum of Natural History . Still, after learning how time-consuming paleontological research was, she looked for positions at Columbia University . 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

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1764-483: 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. The position of Marie Tharp Lamont Research Professor was created in her honor. Created by Lamont in 2004, the Marie Tharp Fellowship is a competitive academic visiting fellowship awarded to women to work with researchers at

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