ALFRED WEGENER ( ) German climatologist and geophysicist who, in 1915, was one of the first to suggest continental drift and plate tectonics. He suggested that a supercontinent he called Pangaea had existed in the past, broke up starting 200 million years ago, and that the pieces “drifted” to their present positions. He cited the fit of South America and Africa, ancient climate similarities, fossil evidence (such as the fern Glossopteris and mesosaurus), and similarity of rock structures.

Africa South America India Australia Antarctica FOSSIL EVIDENCE LYSTROSAURUS GLOSSOPTERIS MESOSAURUS CYNOGNATHUS

What fossil evidence was used by Wegner to support continental drift? For example, the same reptiles, lystrosaurus and mesosaurus, are found in Africa and South America. The same plants, for, example a seed fern called glossopteris is also found on these two continents plus Antarctica, India, etc. These areas now have widely different climates. Reptiles from before 200 m.y. are found in Antarctica.. Opponents thought "land bridges" were the answer. Wegner also noted that since animals in places like Australia and New Zealand had evolved in isolation, they had a radically different population of animals and plants.

a seed fern called glossopteris

Mesosaurus Fossil evidence found on both South America and South Africa

LYSTROSAURUS fossil evidence found in Africa, India and Antarctica

Rock type and structural similarities. In order for a jigsaw puzzle to make sense, the colours and textures of adjacent pieces have to match. Rocks in northwestern Africa match those of eastern Brazil. The Appalachian mountains match mountains in northern Europe just as rock type and structure on a recent spreading center, the Red Sea, match perfectly on either side.

Why is the fit of the continents better now than when proposed by Wegener? We now know that the edges of the continental shelves mark the edges of the continent and not the coastline. A computer fit of these edges show a remarkable fit for North America and Europe and between South America and Africa.

Continental shelf