Distribution of Oceans and Continents

Continental Drift Theory

Proposed by Alfred Wegener in 1912, it suggests that all continents were once joined together as a single supercontinent called Pangaea, surrounded by a mega-ocean called Panthalassa, before breaking apart and drifting to their current positions.

Evidence of Continental Drift

Supportive proofs include the matching of continental coastlines (Jigsaw fit), identical plant and animal fossils found across separated oceans (like Mesosaurus), and matching rock age belts across the Atlantic Ocean.

Convectional Current Theory

Arthur Holmes suggested that thermal convection currents operating in the mantle, driven by radioactive decay, act as the primary driving force behind the movement of crustal plates.

Sea Floor Spreading

Proposed by Harry Hess, this theory states that volcanic eruptions along mid-ocean ridges create new oceanic crust, which continuously pushes older crust away, causing ocean basins to widen.

Plate Tectonics

The modern unified theory stating that the earth's lithosphere is broken into major and minor rigid plates that float on the semi-fluid asthenosphere, interacting at divergent, convergent, and transform boundaries.