Marie Tharp

Her father made soil surveys for the Department of Agriculture, and the family followed the work. By the time he retired in 1931 Marie Tharp had attended more than 17 public schools across Alabama, Iowa, Michigan and Indiana, and had spent enough weekends walking fields with him to know what a map was for. Her mother died when she was 15. She entered Ohio University in 1939, changed her major almost every semester, and left in 1943 with degrees in English and music. That autumn Michigan opened its petroleum geology program to women for the first time, because the men had gone to war and the seats were empty. She took one.

She reached Columbia in 1948 as a drafter, one of the first women hired at Maurice Ewing's Lamont Geological Observatory, and did not mention at the interview that she held a master's in geology. Within a few years she was working for Bruce Heezen alone. He went to sea aboard the Vema and brought back columns of echo-sounder depths. She stayed on land and turned the numbers into physiographic profiles, drawn by hand, six of them stretching west to east across the North Atlantic. Women were not permitted on the ships.

In 1952, aligning those profiles, she saw a V-shaped notch running down the axis of the Mid-Atlantic Ridge and concluded it was a rift valley — which meant the sea floor was pulling apart, and that meant continental drift, a theory most American geologists then rejected. Heezen dismissed it as girl talk and sent her back to redo the plots. It took about a year. When Howard Foster's map of undersea earthquake epicenters was laid over her profiles, the epicenters fell inside her rift, and Heezen came around. She was right. She had never seen the ocean she was drawing: women were barred from Lamont's research vessels, held to be bad luck at sea, and she did not sail until 1968, aboard the USNS Kane. By then Ewing had fired her, and she was mapping at home on Navy contracts.

The first physiographic diagram of the North Atlantic appeared in 1957, drawn as landscape because the government would not allow contour maps of the seafloor to be published. Working with the Austrian panorama painter Heinrich Berann, Tharp and Heezen finished The World Ocean Floor, published by National Geographic in 1977. It showed the public the planet with the water taken off, and the ridge seam running through every ocean was impossible to unsee. Her name appeared on none of the plate tectonics papers Heezen published between 1959 and 1963. Recognition came late: the Society of Woman Geographers honored her in 1996, Lamont-Doherty in 2001. She died of cancer in Nyack, New York, on August 23, 2006.

Marie Tharp's life against the full span of the corpus.

• The Mid-Atlantic Ridge rift valley discovery
  Found in six hand-drawn profiles of the North Atlantic and confirmed against earthquake epicenters 1952
• Physiographic Diagram of the North Atlantic artwork
  Drawn as landscape to get around the ban on publishing seafloor contours 1957
• The Floors of the Oceans I. The North Atlantic book
  With Bruce Heezen and Maurice Ewing, Geological Society of America Special Paper 65 1959
• Tectonic Fabric of the Atlantic and Indian Oceans and Continental Drift article
  With Heezen, in the Philosophical Transactions of the Royal Society 1965
• The World Ocean Floor artwork
  Painted with Heinrich Berann and published by National Geographic 1977

• July 30, 1920 aged 0 Born in Ypsilanti, Michigan Her father surveyed soils for the Department of Agriculture and the family moved with the work.
• 1943 aged ~23 Enters Michigan's petroleum geology program, newly open to women The classrooms had emptied of men. She finished the master's in 1944 and went to Stanolind Oil in Tulsa.
• 1948 aged ~28 Hired as a drafter at Columbia's Lamont Geological Observatory One of the first women there. She did not mention her geology master's at the interview.
• 1952 aged ~32 Identifies a rift valley running down the Mid-Atlantic Ridge Heezen dismissed it as girl talk. Earthquake epicenter maps proved her right.
• 1957 aged ~37 Publishes the first physiographic map of the North Atlantic floor
• 1964 aged ~44 Ewing fires her and she keeps mapping from home Heezen paid her through Navy contracts after Ewing cut off his access to Lamont data.
• 1968 aged ~48 Goes to sea for the first time, aboard the USNS Kane Sixteen years after she found the rift she had never seen.
• 1977 aged ~57 The World Ocean Floor is published Painted with Heinrich Berann for National Geographic.
• August 23, 2006 aged 86 Dies of cancer in Nyack, New York, at 86

• Rachel Carson 1907–1964
  Marine biologist whose book Silent Spring launched the modern environmental movement. wrote the sea she mapped
• Sylvia Earle b. 1935
  Marine biologist and oceanographer known as Her Deepness for her record-breaking underwater explorations. went where she was not allowed
• Charles Richter 1900–1985
  Creator of the earthquake magnitude scale seismology that confirmed the rift
• Barbara McClintock 1902–1992
  Cytogeneticist who discovered transposable elements and won the Nobel Prize in Physiology or Medicine. dismissed, then vindicated
• John Wesley Powell 1834–1902
  Geologist and explorer who led the first documented passage through the Grand Canyon. mapped the unmapped
• Charles David Keeling 1928–2005
  Measured atmospheric carbon dioxide at Mauna Loa from 1958 until his death, producing the Keeling Curve. measured a planet nobody was watching