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High sea levels and tyrannosaurs

70 million years – 70 meters

Tyrannosaurus rex was possibly covered at least partially with feathers. (Walter Myers)

The atmospheric carbondioxide content and the average temperature are high. The oceans are at their maximum height. Most of Europe is covered by a shallow sea. Many chalk deposits, such as the Cliffs of Dover, are formed from the sediments of Haptophyte algaea. Flowering plants are spreading. Dinosaurs are diverse, Triceratops and Tyrannosaurus rex evolves.

Kuva: Sea level were very high at late Cretaceous. Christopher R. Scotese

Late cretaceous period

The volcanic activity at the ocean mid-ridges was at its peak. The carbon dioxide content of the atmosphere was about 4 times and the mean temperatures about 5oC higher than current levels. The ocean surface was 200-300 meters higher than what it is now, and Europe was largely – with the exception of the Scandinavia – covered by the sea. Many of the limestone deposits, such as the white cliffs of Dover in the south coast of England, were formed at this time, as a consequence of the sedimentation of calciferous Haptophyte algae to the bottom of shallow seas. The cretaceous period has got its name by these “cretaceous” deposits. The chalks used for drawing on black boards are pieces of these rocks.

Triceratops at the broadleaf forest. ’Flowering plants’ or Angiosperms became more common during Cretaceous period. Image: Walter Myers

On the dry land, dinosaurs were diverse. The most famous dinosaurs of the late Cretaceous period are 8-9 meter high tree-horned Triceratops horridus, different duck-billed dinosaurs, and the most famous predator dinosaur, Tyrannosaurus rex from Northern American continent. Tyrannosaurus growed up to 12 meters long, and weighted 4,5-6,8 tons. It apparently was both a vicious beast and a carrion-eater. Also one of the largest pterosaurs, Quetzalcoatlus, lived at the end of Cretaceous period. It had wingspan up to 11 meters.

Also insects were diverse. Flora was diversifying and ’flowering plants’ or Angiosperms increased by 30 new genera. Still, grassy plants have not appeared yet, and so there are no savannah or plain types of ecosystems as yet.

Tyrannosaurus rex ja varhainen nisäkäs Purgatorius suvusta. Ei ole varmuutta oliko T. rexillä höyhenpeite. Koska useilta muilta tyrannosauruksilta on löydetty merkkejä höyhenistä, on tähän kuvaan piirretty osittainen höyhenpeite. © Walter Myers

Tyrannosaurus rex and early mammal from genus Purgatorius. It is not known whether T. rex had feathers. However, as some other tyrannosaurs have shown evidence for feathers, partial feather cover has been drawn to this image. Image: Walter Myers