Distribution of Oceans and Continents

Continental Drift Theory

Proposed by Alfred Wegener in 1912, this theory suggests that all continents were once a single supercontinent called Pangea, surrounded by a mega-ocean called Panthalassa, and eventually broke apart and drifted to their current positions.

Pangaea and Panthalassa

Pangaea represents the ancient supercontinent comprising all present-day landmasses, while Panthalassa was the massive universal ocean that surrounded Pangaea before the continental drift began.

Convectional Current Theory

Proposed by Arthur Holmes, this theory suggests that intense heat generated by radioactive decay in the earth's interior creates thermal convection currents in the mantle, driving the movement of crustal plates.

Seafloor Spreading

A concept introduced by Harry Hess stating that volcanic magma upwells along mid-ocean ridges, creating new oceanic crust that pushes older crust away, causing ocean basins to widen over time.

Plate Tectonics

A unifying geological theory stating that the lithosphere is broken into rigid tectonic plates that float on the asthenosphere, interacting at convergent, divergent, and transform boundaries to shape the earth's relief.