Browsing the "Cretaceous" Category

The Cretaceous period is a division of earth’s history spanning from around 145 to 66 million years ago, and during which enormous deposits of Chalk were formed across Europe. The Cretaceous was a warm period with temperatures on average 4°C above present. Sea levels gradually rose through the Cretaceous; attaining a maximum of around 200 meters above the present level, and resulting in the formation of shallow seas as large areas of the continents became flooded. During the Cretaceous the supercontinents of Laurasia and Gondwana continued to break up; opening the Indian and Atlantic Oceans. In the oceans, teleosts, a major group of bony fish, began to flourish along with modern sharks and rays. Diatoms, a group of planktonic algae, also began to diversify. On land the first true mammals and birds evolved while dinosaurs remained dominant. A major floral revolution took place during the Cretaceous with the emergence and gradual diversification of flowering plants. The end of the Cretaceous is marked by one of the most catastrophic extinctions in earth’s history. Dinosaurs, pterosaurs, ammonites, belemnites, rudist bivalves and many groups of marine reptiles were among those wiped out. An Iridium rich layer found globally at the Cretaceous/Paleogene boundary, along with a vast impact crater in Mexico, lead many to believe that a meteor was responsible for the end Cretaceous extinction. However, massive volcanism in India, contemporaneous with the extinction, may also have been a contributing factor.

Cretaceous

Episode 91: Dinosaurs of Appalachia

Published on May 24th, 2018 | by David Marshall

The Appalachian mountains, span the Eastern margin of the United States of America. They are predominantly composed of Paleozoic rocks, but Mesozoic marine sediments (formed adjacent to the Appalachian continent at the time) can be found [&hellip... Read More


Cretaceous

Episode 90: Ichthyornis

Published on May 3rd, 2018 | by Liz Martin-Silverstone

Bird evolution has long fascinated palaeontologists. Despite crown-group birds (birds giving rise to modern lineages today) evolving during the Cretaceous, there are relatively few fossils from this time, making it difficult to understand this key time [&hellip... Read More


Cretaceous

Episode 85: Ichthyosaurs

Published on January 7th, 2018 | by David Marshall

Ichthyosaurs are large marine reptiles that existed for most of the Mesozoic Era. The most familiar forms superficially represent dolphins, but some earlier ichthyosaurs were more eel like. They could attain huge proportions, with some genera [&hellip... Read More


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My Favourite Question

Published on December 10th, 2017 | by Guest Blogger

Or what a difference a word makes. Words have meaning. That meaning gives them power. Two essentially identical sentences can have entirely different meanings just by changing a single word. In some cases, that word can [&hellip... Read More


Cretaceous

Episode 82: Dinosaurs of China

Published on October 17th, 2017 | by David Marshall

‘Dinosaurs of China’ at Wollaton Hall, Nottingham, UK,  is a one-time only world exclusive exhibition of dinosaurs. Featuring fossils and specimens never before seen outside of Asia, the collection brings to life the story of how [&hellip... Read More


Cretaceous

Episode 81: Coccolithophores

Published on October 1st, 2017 | by David Marshall

Coccolithophores are tiny unicellular eukaryotic phytoplankton (algae). Each is covered with even smaller calcium carbonate plates called coccoliths and it is these that are commonly preserved in the fossil record. In fact, coccoliths are so small, [&hellip... Read More


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Evidence of Intense Predation Pressures on Ancient Megafauna

Published on August 4th, 2017 | by Chris Barker

Biology is full of exciting avenues, and some of the finest, in my opinion, are the morphological and behavioural adaptations that define the split seconds whether an animal lives or dies, eats or starves. Predator-prey interactions [&hellip... Read More


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Playing Doctor with Titanosaurs

Published on July 30th, 2017 | by Chris Barker

Titanosaurs include some of the largest terrestrial organisms to walk the Earth: globally distributed, multi-tonne behemoths representing the last of the sauropods at the end Cretaceous extinction event. Much about their biology is known, ranging from [&hellip... Read More


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New Oviraptorid Shows Cassowary Convergence

Published on July 29th, 2017 | by Chris Barker

The Late Cretaceous rocks of Ganzhou, China, are rife with oviraptorids. We have seen these strange theropods before here at Palaeocast, when we looked at the very high temperatures at which they incubated their eggs. The [&hellip... Read More


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