This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Marie Tharp was born July 30, 1920 in Ypsilanti, Michigan. Already in early years she followed her father, a soil surveyor for the United States Department of Agriculture, into the field. However she also loved to read and wanted to study literature at St. John's College in Annapolis, but at the time women were not admitted there. So she went to Ohio University, where she graduated in 1943.
The Second World War changed dramatically the situation in the United States - the nation needed highly educated replacement for the men who went into war and women were now encouraged to obtain degrees also in "manly" disciplines, like science and technology. Marie enrolled in a petroleum geology program, becoming so one of the first "Petroleum Geology Girl" when she graduated in 1944. She worked for a short time in the petroleum industry, but found the work unrewarding and decided to resume her studies at Tulsa University.
In 1948 she graduated in mathematics and found work at the Lamont Geological Laboratory of Columbia University.
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During the Cold War money for various geological projects - like studying and mapping the ocean floor, the battlefield for a possible future war with submarines - was more than abundant.
Marie started a prolific collaboration with geologist Bruce Charles Heezen (1924 -1977), specialist for seismic and topographic data obtained from the sea floor. As women, Marie was not allowed on board of the research vessels crossing over the sea to collect the raw data, so she started to calculate, interpret and visualize the obtained information when Heezen went to the sea. She co-authored with Heezen a book and various papers; however her work was often undervalued - sometimes bureaucracy and financial troubles at her department forced Marie to work from home.
Between 1959 until the death of Heezen in 1977, she worked strenuously on various maps that would depict the still unknown topography of the oceanic basins - and the results were astounding. The ocean floor was not a flat plain of mud, as previously imagined, but displayed mountains, ridges and canyons, sometimes larger and deeper than any feature found on the continents. The most impressive feature however was a chain of mountains (of madness) cutting in half the large basins of the oceans - Tharp and Heezen had discovered the backbone of earth, the Mid-Ocean Ridges.
The figure shows Marie Tharp "[I was] so busy making maps I let them argue,...[]" (photography published in HEEZEN & HOLLISTER 1971, it is believed that the use of low-resolution images qualifies as fair use under United States copyright law). Both Heezen and Tharp recognized the Mid-Ocean Ridges as spreading centers of the oceanic crust; however both tended to consider this a result of an expanding globe. Nevertheless Marie Tharp´s cartographic accomplishments were exceptional because she overcame educational and employment barriers that limited opportunities for women of her generation. Without doubts she prepared the field for other researchers; however she will not play a direct role in the development of one of the most revolutionary geological theory of all times - plate tectonics.
Bibliography:
BARTON, C. (2002): Marie Tharp, oceanographic cartographer, and her contributions to the revolution in the Earth sciences. In OLDROYD, D.R. (ed.) The Earth Inside and Out: Some Major Contributions to Geology in the Twentieth Century. Geological Society Special Publications 192, London: 215-228
HEEZEN, B.C. & HOLLISTER, C. D. (1971): The face of the deep. Oxford Univ. Press, New York, London, and Toronto: 659