Supporting Wegener’s theory of continental drift, Hess explained how the once-joined continents had separated into the seven that exist today.
What did Harry Hess contribute to the continental drift idea? Hess discovered that the oceans were shallower in the middle and identified the presence of Mid Ocean Ridges, raised above the surrounding generally flat sea floor (abyssal plain) by as much as 1.5 km. What did Harry Hammond Hess realize in the 1950s? … After much thought, he proposed in 1960 that the movement of the continents was a result of sea-floor spreading. Part of his mission had been to study the deepest parts of the ocean floor. Harry Hess was a geologist and Navy submarine commander during World War II. In 1959, he informally presented this hypothesis in a manuscript that was widely circulated. What was Harry Hess hypothesis called?īuilding on the work of English geologist Arthur Holmes in the 1930s, Hess’ research ultimately resulted in a ground-breaking hypothesis that later would be called seafloor spreading. … This spreading creates a successively younger ocean floor, and the flow of material is thought to bring about the migration, or drifting apart, of the continents. The seafloor spreading hypothesis was proposed by the American geophysicist Harry H. Read more about Marie Tharp in this blogpost by David Bressan, Marie’s reflections that I quoted from, and this obituary from the Lamont-Doherty Earth Observatory (formerly the Lamont Geological Observatory).32 Is the supercontinent? What is Hess's theory of seafloor spreading? By the time Marie retired in 1983, plate tectonics had been widely accepted she had witnessed - and helped to foster - a complete transformation of her field. While they never argued for continental drift, their maps and their interpretation of the ridges spurred the debate and prompted others to propose new mechanisms and theories. Together, Marie and Bruce published the first physiographic map of the North Atlantic in 1957, and over the following 20 years they extended their mapping to all of the world’s oceans. “I thought it might be a rift valley that cut into the ridge at its crest and continued all along its axis,” she said. This was a controversial assertion during the decades-long debate over continental drift. In 1952, Marie identified a key feature of the ridge dividing the North Atlantic: a V-shaped cleft running perfectly through its center. Tharp quickly became responsible for organizing and compiling the ocean sounding data sent back by Bruce Hazeen on his research voyages. Having earned degrees in geology and mathematics, she moved to Columbia University’s Lamont Geological Observatory in 1948. Marie Tharp’s work revealed that world to us for the first time. Oceans cover most of the surface area of our planet, hiding a worldwide network of magnificent, rugged mountain chains where new crust is formed and pushed outward. In the work she’s most known for, Marie Tharp wielded not a trowel but a pen, but from her drafting table at the Lamont Geological Observatory in Palisades, NY, she could see the entire ocean floor. Image source: Lamont Archives, Lamont-Doherty Earth Observatory. Marie Tharp, sitting at her desk at Columbia’s Lamont Geological Observatory, 1956.
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