Alfred Wegener proposed the continental-drift theory in 1912, helping lead to modern plate tectonics.
Wegener argued that today’s continents were once joined in a supercontinent he called Pangaea. He cited the matching shapes of continental margins, related fossils on now-separated landmasses, and geological similarities across the Atlantic Ocean.
His evidence was influential but incomplete. Wegener could not provide a convincing physical mechanism for moving entire continents through oceanic crust, so many geologists initially rejected the idea. Later discoveries supplied that missing framework.
Evidence for seafloor spreading, symmetrical magnetic stripes on oceanic crust, and global earthquake and volcano patterns helped establish plate tectonics in the 1960s. Modern theory says continents move as parts of larger lithospheric plates, rather than plowing independently through the seafloor. Wegener’s original proposal was therefore an important precursor, not a complete version of modern plate tectonics.