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. 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.
Early life and education 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. She often accompanied her father on his fieldwork, which gave her an early introduction to mapmaking. Due to 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 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 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 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 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.
Career In 1948, Tharp moved to New York City after four years in Tulsa. She initially sought work at the American Museum of Natural History, and later looked for positions at Columbia University because of how time-consuming paleontological research was. Tharp was hired to do 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. 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 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 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.
Continental drift theory
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