The correct option is Harry Hess.
Explanation
The hypothesis of Sea Floor Spreading was a pivotal concept that bridged the gap between the earlier Continental Drift Theory and the modern Theory of Plate Tectonics. It provided the mechanism explaining how continents move and how new oceanic crust is generated.
Option-wise Analysis
- Alfred Wegener Alfred Wegener: Incorrect. Wegener propounded the Continental Drift Theory in 1912. He suggested that continents were once a single supercontinent called Pangea but failed to explain the driving force behind their movement.
- Arthur Holmes Arthur Holmes: Incorrect. Holmes proposed the Convection Current Theory in the 1930s. He suggested that convection currents operating in the mantle could be the force responsible for drifting continents. This theory later influenced the development of Sea Floor Spreading.
- Harry Hess Harry Hess: Correct. Harry Hess propounded the hypothesis of Sea Floor Spreading in 1961. He argued that constant volcanic eruptions at the crest of oceanic ridges cause the rupture of the oceanic crust, where new lava wedges into it, pushing the oceanic crust on either side. The ocean floor thus spreads.
- McKenzie and Parker McKenzie and Parker: Incorrect. McKenzie and Parker, along with W.J. Morgan, are credited with independently collecting the available ideas (including Sea Floor Spreading) to formulate the comprehensive Plate Tectonics Theory in 1967.
Key Takeaway
Harry Hess proposed Sea Floor Spreading, suggesting that new oceanic crust is created at mid-ocean ridges and consumed at oceanic trenches, thereby resolving the mechanism for continental drift.