Harry Hammond Hess was a geologist whose seafloor spreading hypothesis connected production of oceanic crust at spreading ridges with its return to the mantle at subduction zones. The moving ocean floor supplied a mechanism for large-scale rearrangement of continents without requiring continents to plough through a stationary ocean floor. During naval service he used sonar surveys to investigate ocean-basin bathymetry; his 1962 paper History of Ocean Basins developed the geological hypothesis.[ref]
https://pubs.usgs.gov/gip/dynamic/HHH.html. USGS, Harry Hammond Hess: Spreading the seafloor; wartime surveys and the 1962 paper
The hypothesis also addressed a puzzle: ancient oceans need not contain equally ancient oceanic crust if the ocean floor is continually renewed and recycled. Increasing ocean-floor age away from spreading ridges, paired marine magnetic stripes and earthquakes along descending slabs later supplied independent tests of seafloor spreading and subduction. These observations turned an initially sparsely constrained proposal into part of plate tectonics.[ref]
https://pubs.usgs.gov/gip/dynamic/HHH.html. USGS, tests from magnetic striping, ocean-floor ages and seismic observations
Portrait of Harry Hammond Hess
. Historical USGS photograph of Hess in naval uniform. The Commons file page lists the photographer as unknown and identifies the image as public domain USGS material. Source.
Harry Hammond Hess (1906–1969) was an American geologist and a major figure in the development of the theory of plate tectonics. He is best known for his contributions to the understanding of seafloor spreading, a key concept in the theory of plate tectonics which explains how new oceanic crust is formed at mid-ocean ridges and how it subsequently moves away from the ridges, causing continental drift.
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