Wegener, Alfred Lothar (1880–1930)

German meteorologist and geophysicist whose theory of continental drift, expounded in Origin of Continents and Oceans in 1915, was originally known as ‘Wegener's hypothesis’. His ideas can now be explained in terms of plate tectonics, the idea that the Earth's crust consists of a number of plates, all moving with respect to one another.

Wegener was born in Berlin and studied at Heidelberg, Innsbruck, and Berlin. From 1924 he was professor of meteorology and geophysics at Graz, Austria. He completed three expeditions to Greenland and died on a fourth.

Wegener supposed that a united supercontinent, Pangaea, had existed in the Mesozoic. This had developed numerous fractures and had drifted apart some 200 million years ago. During the Cretaceous, South America and Africa had largely been split, but not until the end of the Quaternary had North America and Europe finally separated; the same was true of the break between South America and Antarctica. Australia had been severed from Antarctica during the Eocene.