Earth Dynamics During the Age of Dinosaurs

The Age of Dinosaurs, scientifically known as the Mesozoic Era, lasted from approximately 252 to 66 million years ago. It was divided into three major periods: the Triassic, Jurassic, and Cretaceous.During this time, the Earth looked very different from today. The continents were not in their present positions. At the beginning of the Mesozoic Era, most landmasses were joined together as a supercontinent called Pangaea. The climate during the Mesozoic was generally warmer than today, with relatively high global temperatures and no permanent polar ice sheets for much of the era. This warm climate supported extensive forests and diverse ecosystems. Large areas were covered by lush vegetation, providing food for enormous herbivorous dinosaurs. 
Atmospheric carbon dioxide levels were also generally higher than present-day levels, although they varied considerably throughout the era.Sea levels were often high, particularly during parts of the Cretaceous Period, allowing shallow seas to cover areas that are now dry land.The Mesozoic also witnessed major evolutionary changes, including the diversification of dinosaurs, marine reptiles, flying reptiles, and early mammals.
The end of the dinosaur era was marked by a dramatic environmental change approximately 66 million years ago. A large asteroid impact near what is now Mexico caused enormous environmental disruption
Combined with other environmental factors, this event contributed to the mass extinction that eliminated non-avian dinosaurs.