Drifting Continents

Article | Updated 10 years ago

During the Cretaceous, as well as throughout the Earth’s history, the continents have slowly moved position. This movement affects the evolution of life on Earth including dinosaurs.

How do they move?

The Earth’s lithosphere (the crust and uppermost part of the hot mantle below) is divided into seven large and a few smaller, curved plates that move constantly, relative to each other. Continents have old, thick, but relatively light crust, whereas the ocean floor has young, thin and dense crust. Whenever the two types of crust collide, the denser oceanic crust will dive under the lighter continental crust and eventually melt deep in the interior of the planet. Some of the molten rock will rise as magma through the continental crust to form a chain of mountain-building volcanoes. New oceanic crust is continually formed at mid-oceanic ridges where two plates are moving away from each other.

Drifting dinosaurs

The slow reshaping of the Earth’s crust had a major impact on the evolution of dinosaurs. In the Cretaceous, sea levels rose flooding the continents. By the Late Cretaceous dinosaurs became isolated on small islands in what is now central Europe and evolved into new and strange forms, like dwarfed sauropods.