Final answer:
Alfred Wegener is credited with proposing the concept of continental drift and the existence of a supercontinent named Pangaea, supported by evidence of continental fit, fossils, mountains, and climate data. His theory faced scepticism due to the lack of a mechanism but was later supported by plate tectonics developments.
Step-by-step explanation:
The supercontinent proposed by Alfred Wegener that is believed to have existed before breaking up due to continental drift is called Pangaea. Wegener, a German scientist, introduced the concept of continental drift in 1915, along with several pieces of evidence to support his revolutionary idea. These included the jigsaw-like fit of the continents, matching fossils on continents separated by oceans, corresponding mountain ranges, and paleoclimatic data suggesting past positions of continents relative to the poles and equator. Despite providing substantial evidence, Wegener faced significant scepticism because he could not provide a mechanism explaining how the continents could drift. The theory was not widely accepted until advancements in geology, oceanography, and geophysics in the 1960s helped to establish the theory of plate tectonics.