Geological Timeline: The Cretaceous Period

The Geological Timeline is like a giant calendar that scientists use to understand Earth’s long history. It helps us to see how the planet has changed over 4.6 billion years. Each time period has special names and tells us about the different plants, animals, and landscapes that existed then. By studying rocks and fossils, scientists can piece together this amazing story of Earth!

The age of dinosaurs is called the Mesozoic age. It is divided into three time periods, the Triassic, the Jurassic, and the Cretaceous - which was when a lot of different kinds of dinosaurs lived!

The Cretaceous period was the heyday of the dinosaurs. Huge carnivores like Tyrannosaurus rex and Giganotosaurus appeared, as did Triceratops and many, many others. There was a tremendous diversity in dinosaur species!

The breakup of the supercontinent Pangaea into separate continents was underway. The separation of Laurasia and Gondwana was complete. In the first half of the Cretaceous period, temperatures were warm, seasonality was low and global sea levels were high. At the end of the Cretaceous period, there were severe climate changes, lowered sea levels and high volcanic activity.

Mammals were flourishing during the Cretaceous period and the first flowering plants appeared offering new sources of food. These flowering plants began to radically change the landscape.

The earliest fossils of birds were also from the Cretaceous period, including species like loons, grebes, pelicans and flamingos!

What was Texas like during the Cretaceous period?

Much of the state of Texas was at or around sea-level during this time, meaning it was covered with water at different times during this period. There was no polar ice during the mild warm, subtropical Cretaceous. The Lonestar state was especially steamy and swampy. The parts that weren't too deeply under water provided the perfect hot, humid environment for dinosaurs.

Texas was a place of many geological and biological changes during the Cretaceous period!