ABSTRACT

BACKGROUND: THE K / T BOUNDARY AND THE EXTINC TION OF THE DINOSAURS The onset of the Cretaceous Period saw the continued break-up of the supercontinent of Pangea, owing to movements deep in the Earth’s mantle. Initially North America and Europe pulled apart, opening up the North Atlantic Ocean, and by the end of the early Cretaceous South America and Africa also began to cleave apart to form the South Atlantic. Meanwhile the Tethys Ocean extended westwards so that the northern continents were divided from those in the south. This loss of land bridges and migration routes led to a diversification of animal and plant life on separated continents.