• Harry Hess was a geology professor and a naval officer.
  • He commanded an attack transport ship during WWII.
  • Hess was intrigued by the seafloor maps produced with the ship's echo sounder.
  • He thought about all of the evidence for continental drift.
  • And he found the mechanism to explain them all.
  • Convection currents within the mantle drive the continents.
  • The continents are pushed by oceanic crust, like they are on a conveyor belt.
  • The spreading plate takes along any continent that rides on it.
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