Jurassic Period FACT FILE

The Jurassic (/dʒuːˈræsɪk/; from Jura Mountains of the Alps) is a geologic period and system that extends from 201.3± 0.6 Ma (million years ago) to 145± 4 Ma.

*Based on 'The Geologic Time Scale 2012' by F M Gradstein, J G Ogg, M Schmitz & G Ogg (2012), with additions. Credit: British Geological Survey

The start of the period is marked by the major end Triassic extinction event.


The end of the period marked more by a marine extinction event possibly due to the opening of the Tethys, creating new global ocean circulation.  Changes in salinity and the release of ocean hydrates may also have played a part.

The Jurassic was the most diverse period in Earth history.


The largest dinosaurs of the time — in fact, the largest land animals of all time — were the gigantic sauropods, such as the famous Diplodocus, Brachiosaurus and Apatosaurus. Other herbivorous dinosaurs of the Jurassic included the plated stegosaurs.


The Jurassic also saw the origination of the first birds, including the well-known Archaeopteryx, probably from coelurosaurian ancestors.


Ichthyosaurs were at their height, sharing the oceans with the plesiosaurs, giant marine crocodiles, and modern-looking sharks and rays. Also prominent in the seas were cephalopods such as ammonites.


The BBC Nature website has a very good section on the Jurassic.  


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The British Geological Survey website has an excellent section on the Jurassic environment.  


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