The T-Rex and other Jurassic and Cretaceous dinosaurs thrived because of volcanic eruptions warming up the Earth, a study has found.
Scientists from the University of Bristol have discovered a new major extinction event which occurred because of massive volcanic eruptions in the Wrangellia Province of western Canada, where huge volumes of volcanic basalt was poured out and forms much of the western coast of North America.
In the paper, published today in Science Advances, researchers lay out the evidence for a major extinction of life 233 million years ago that triggered the dinosaur takeover of the world. The crisis has been called the Carnian Pluvial Episode.
The volcanic eruptions pumped out huge quantities of carbon dioxide, warming the Earth and causing much life to die out, changing the landscape.
Dinosaurs originated some time before the event, but were "rare and unimportant" until the arid conditions caused by the eruptions took place, scientists explained.
"The new floras probably provided slim pickings for the surviving herbivorous reptiles," said Professor Mike Benton from the University of Bristol.
"I had noted a floral switch and ecological catastrophe among the herbivores back in 1983 when I completed my PhD. We now know that dinosaurs originated some 20 million years before this event, but they remained quite rare and unimportant until the Carnian Pluvial Episode hit. It was the sudden arid conditions after the humid episode that gave dinosaurs their chance."
Many modern groups of plants and animals also appeared after the extinction event, including some of the first turtles, crocodiles, lizards, and the first mammals.
Coral reefs also have the volcanoes to thank for their current form, as the ocean chemistry and carbonate cycle were changed by the release of carbon dioxide. Ocean life likely is what it is today because these changes also impacted the types of plankton which thrived in the sea.
"So far, palaeontologists had identified five "big" mass extinctions in the past 500 million yeas of the history of life," co-author Jacopo Dal Corso from theChina University of Geosciences at Wuhan said.
"Each of these had a profound effect on the evolution of the Earth and of life. We have identified another great extinction event, and it evidently had a major role in helping to reset life on land and in the oceans, marking the origins of modern ecosystems."