On a world map, the
east coastline of South America bears an uncanny likeness to the shape of the
west coast of Africa. Look at the edges of the continental shelves of these two
continents, a couple of hundred metres under the sea's surface, and the
resemblance is even more striking. The two would fit together like pieces of a
giant jigsaw. In fact, they once did. The idea of continental drift, once
dismissed out of hand, is now well established in science. The major land
masses or continents have changed less through time than the Earth's crust
under the oceans. The oceanic crust has continually formed new patches from
molten rocks welling up from below, while other patches melt back into the depths
again. The continents have been carried around like giant rafts on these changing
shapes of oceanic crust.
-- Part of the
evidence Evidence for
continental drift comes from many areas, including fossils. Remains of the reptile
Lystrosaurus have been found in South Africa, Antarctica, India and
China, suggesting these lands were joined many years ago.
-- First to propose The idea of
continental drift has been around for centuries. First to propose a scientific
explanation was German weather expert Alfred Wegener (1880-1930), in 1912. But
political problems, world wars and Wegener’s background in meteorology meant
his suggestions were not taken seriously until 1960s. (Adapted from 'World of Science')
