Soundings: The Story of the Remarkable Woman Who Mapped the Ocean Floor

  • Hali Felt
  • Henry Holt
  • 352 pp.

Despite barriers to professional advancement for women scientists in the mid-1900s, Marie Tharp was a pioneer in the mapping of ocean-floor territory.

Reviewed by Andrea D. Cicero

My father was a lifelong member of National Geographic Society, and each month a new glossy magazine would appear in the mail. Though each volume was full of pictures and stories from places afar, the best volumes were those that came with a pullout map. I could spend hours on the floor with the maps opened in front of me, studying the intricate details. Especially intriguing were maps of the seafloor, illustrated in varying shades of blues and greens. I pored over these maps completely unaware of the pioneering woman scientist who created them: Ms. Marie Tharp.

Hali Felt’s artfully written biography of Marie Tharp, Soundings: The Story of the Remarkable Woman Who Mapped the Ocean Floor, sheds light on the life and scientific accomplishments of the oceanographic cartographer, geologist, and mathematician whose maps and interpretations caused one of the biggest paradigm shifts in the history of geology. The concept of continental drift was hypothesized as early as 1910, based on the observation that continents today fit together like puzzle pieces. For example, look at a map and see how neatly the eastern coast of South America seems to fit with the western shore of Africa. The mechanisms by which continents could move, however, were unknown.

The physiographic maps of the earth’s seafloor that Marie Tharp painstakingly illustrated depicted a continuous positive subaqueous feature, the Mid-ocean ridge, which extended across the world’s oceans for nearly 50,000 miles. Marie also noted the existence of a “deep notch near the crest of the ridge” where “new material came from deep inside the Earth, splitting the Mid-ocean ridge in two and pushing the sides apart. That, in turn, would move the continents on their various tectonic plates.” (Iceland, we now realize, is a place where the Mid-ocean ridge rises above the surface of the sea.) By 1960, the theory of plate tectonics as we know it today came into existence; it is still taught as a basic tenet of geology.

The book covers Marie Tharp’s humble start as a child; through her college years, where she studied a diverse number of subjects, including music, English, and geology; through graduate school at the University of Michigan; to her first job as a geologist’s assistant for an oil company; to obtaining a second bachelor’s degree in mathematics. In 1948 she moved to New York and joined the staff at Columbia University’s geophysical department (now known as the Lamont Doherty Earth Observatory) as a “human calculator,” punching numbers to solve seismology equations.

Given the socially accepted roles of women in the sciences during the late 1940s and 1950s, Marie’s responsibilities at Columbia were limited. She was one of the few women employed at the department, and the only woman in a non-administrative role. Although she held degrees in both geology and mathematics, Marie’s main responsibilities — apart from the seismological functions she calculated — were that of a draftswoman. Her undergraduate mentor, Dr. Dow, suggested that she learn to draft, since there “was a good chance that no one would let her do fieldwork, but if she could draft, she could work in an office.” She supported her younger and less educated male counterparts by providing figures and diagrams. Her gender made it impossible to accompany the scientists on ocean cruises, collecting data and performing on-board research.

Frustrated in her diminutive role after four years at Columbia, she left suddenly to move back to her family home. Yet, with encouragement from the department chair, Dr. Maurice Ewing, Marie returned to Columbia and into the service of Dr. Bruce Heezen. Bruce was the first person at Columbia who allowed her to think for herself, letting her analyze the rolls of fathometer readings he brought back from his voyages and draft the first physiographic depictions of the seafloor. Bruce treated her as a colleague and an equal, entrusting her with the data and believing her capable of interpreting it.

Marie’s first oceanographic profiles depicted the Mid-ocean ridge and its associated rift valleys in six separate transects. Using her background in geology, and observations of landform relationships, Marie interpolated between transects in areas where no data existed, suggesting the ridge and rifts were continuous features. Later, when she laid maps of earthquake centers atop the physiographic profiles, she observed that most of the earthquake activity took place within the drafted rift valleys, and extended linearly between oceanographic profiles. It is unclear whether the idea to overlay earthquake centers atop Marie’s profiles was Bruce’s or hers, but the results were clear: this was the definitive multi-disciplinary evidence Marie and Bruce needed before publishing their work.

Their findings, when first published in 1956 (without Marie listed as an author), were received very critically. Only when Jacques Cousteau provided video footage of the claimed Mid-ocean ridge and associated rift valley did the scientific world take Marie and Bruce’s work seriously. Marie first earned credit for her work in a series of published maps, and in time, subsequent publications bore her name. Questions surrounding authorship of publications led to a breakdown of the relationship between this scientific team and Columbia University. Despite her substantial contributions, Marie was often excluded from authorship. An international conference proved to be a main catalyst for this breakdown: the department chair believed only Bruce should attend, yet the keynote address Bruce was invited to give featured Marie’s work, and her presence was necessary. While Bruce was the main recipient of what Marie called “The Harassment,” the strained relationship between Bruce and Columbia also provided the impetus for Marie to leave Columbia’s campus in 1965 and work in collaboration with Bruce solely out of her home in Nyack, New York for the remainder of her career.

Hali Felt’s well-written biography explores a number of themes still pertinent today; those who are interested in paradigm shifts and the evolution of scientific thought, the roles of women in science throughout history, and the politics of academic life should consider reading it. As a geologist, I found that some of the scientific concepts were oversimplified, and the author took great liberties in recreating Marie’s thoughts and feelings in response to specific situations where there was no direct evidence to support them. However, she provides a robust appendix of references for the basis of her assumptions. By making these assumptions, or interpolations, just as Marie Tharp did, she humanizes the work for the more general reading public. Anyone interested in the life story of a female scientific pioneer and the above-noted themes will find it a worthy and interesting read.

Andrea D. Cicero is a native New Yorker turned Houston-based exploration geologist working in the oil and gas industry. She attained her undergraduate degree in geology at The State University of New York at Binghamton, and like Marie Tharp, her master’s degree in geology at The University of Michigan. When not making maps of her own, she enjoys performing with a community band, learning languages, working out, and traveling.

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