Geologist-cartographer Marie Tharp turned echo-sounding numbers into the first global seafloor maps—revealing the Mid-Atlantic Ridge’s rift valley and helping vindicate Alfred Wegener’s once-dismissed theory of continental drift. This episode traces Tharp’s path from wartime classrooms to world-changing maps, the resistance she faced, and the recognition that finally followed.

Three Key Points:

1. How Tharp and Bruce Heezen transformed sonar data into the physiographic maps that visualized seafloor spreading.
2. Why the Mid-Atlantic Ridge’s rift valley was a “smoking gun” for plate tectonics.
3. How gender bias delayed credit for one of geology’s most consequential discoveries.

Resources & Further Reading (links)

• World / Ocean Floors and Land Relief (Heezen–Tharp map) at the David Rumsey Collection. David Rumsey Map Collection
• Browse all Tharp items in the David Rumsey Historical Map Collection. David Rumsey Map Collection
• Library of Congress Heezen–Tharp Collection (finding aid & digitized items). Library of Congress Handle Resolver
• About Marie Tharp (Lamont-Doherty Earth Observatory mini-site). marietharp.ldeo.columbia.edu
• Marie Tharp biography (Woods Hole Oceanographic Institution). Woods Hole Oceanographic Institution
• SECNAV press release renaming USNS Marie Tharp (T-AGS-66), Mar 8, 2023. Navy+1
• Google Doodle celebrating Marie Tharp (interactive). Google Doodleslamont.columbia.edu

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Music: All music is public domain and has no Copyright and no rights reserved.
Selections from The Little Prince by Lloyd Rodgers. From Page to Practice by Brian Teoh. Nature Documentary by Alisia Beats. Slow Tide by u_98673jp94. 

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