The correct option is Harry Hess.
Explanation
The mechanism described is known as the Sea Floor Spreading Theory. It postulates that the ocean floor is not a static surface but a dynamic structure that moves like a conveyor belt. New oceanic crust is generated at mid-ocean ridges through volcanic activity and is subsequently destroyed or consumed at ocean trenches (subduction zones).
Analysis of Options:
- Alfred Wegener Alfred Wegener: Incorrect. Wegener proposed the Continental Drift Theory in 1912. While he suggested that continents moved, he believed the continents plowed through the ocean floor. He failed to explain the mechanism of movement, attributing it incorrectly to tidal forces and the "pole-fleeing force."
- Harry Hess Harry Hess: Correct. In 1961, Harry Hess proposed the Sea Floor Spreading Theory. He argued that constant eruptions at the crest of oceanic ridges cause the rupture of the oceanic crust and the new lava wedges into it, pushing the oceanic crust on either side. The ocean floor spreads from the mid-ocean ridges and eventually sinks at the oceanic trenches.
- Arthur Holmes Arthur Holmes: Incorrect. Arthur Holmes proposed the Convection Current Theory in the 1930s. He suggested that convection currents operating in the mantle could be the force behind drifting. While his work provided the driving mechanism (mantle convection) that Hess later utilized, Holmes did not propose the specific cycle of ridge spreading and trench subduction.
- Antonio Pellegrini Antonio Pellegrini: Incorrect. Antonio Snider-Pellegrini was a geographer who, in 1858, drew maps showing how the American and African continents could fit together, serving as an early precursor to the idea of continental drift, but he did not propose the mechanism of sea floor spreading.
Key Takeaway:
Harry Hess is credited with the Sea Floor Spreading Theory, which provided the critical mechanism explaining how continents move, bridging the gap between Continental Drift and modern Plate Tectonics.