Home > Plate Tectonics: A Scientific Revolution Unfolds > Concept #2 Quiz
fossil evidence between S. America and Africa mid-ocean ridge system, middle of the Atlantic Ocean fossil evidence between India and Africa magnetic stripes on the ocean floor
symmetry of the ages of rocks across mid-ocean ridges seismic data to locate mid-ocean ridges fossil evidence in the ocean crust across mid-ocean ridges symmetry of magnetic data across mid-ocean ridges
Sinking material in the mantle spreads laterally, forcing seafloor into continents at the edges of ocean basins. Rising material in the mantle spreads laterally, carrying the seafloor away from seafloor ridges in the center of the ocean basin. Sinking material in the mantle causes seafloor to diverge at the edges of continents. Rising material in the seafloor and ocean basin causes the seafloor to spread laterally away from continents.
oceanic ridges are located above zones of mantle upwelling old seafloor crust descends back into the mantle at deep ocean trenches continents "plow" through the seafloor, away from ocean ridges new crust is formed at the ridge crest as old seafloor migrates away from it in both directions mantle upwelling
parallel magnetic stripes recorded in ocean floor mountain belts between different bits of crust tsunamis continental drift hypothesis / seafloor spreading idea
Harry Hess was a better scientist. Seafloor spreading is more plausible than continents cutting through seafloor. The seafloor spreading hypothesis provided many more testable ideas. The seafloor spreading hypothesis made more sense to people opposed to continental drift.