Summary of major extinction events through time, highlighting the new, Carnian Pluvial Episode at 233 million years ago. Credit: D. Bonadonna/ MUSE, Trento
SciTechDaily has a story about the identification of a new mass extinction. This one called the "Carnian Pluvial Episode". It occurred about 233 million years ago during the Triassic Period. The cause is believed to be flood basaltic volcanic eruptions in western Canada. Some of the outcomes was the rise of the dinosaurs and the arrival of the very first mammals and turtles. You can find more details in a paper, which appeared in the journal Science Advances.
It’s not often a new mass extinction is identified; after all, such events were so devastating they really stand out in the fossil record. In a new paper, published today in Science Advances, an international team has identified 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 team of 17 researchers, led by Jacopo Dal Corso of the China University of Geosciences at Wuhan and Mike Benton of the University of Bristol’s School of Earth Sciences, reviewed all the geological and palaeontological evidence and determined what had happened.
The cause was most likely 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.
“The eruptions peaked in the Carnian,” says Jacopo Dal Corso. “I was studying the geochemical signature of the eruptions a few years ago and identified some massive effects on the atmosphere worldwide. The eruptions were so huge, they pumped vast amounts of greenhouse gases like carbon dioxide, and there were spikes of global warming.” The warming was associated with increased rainfall, and this had been detected back in the 1980s by geologists Mike Simms and Alastair Ruffell as a humid episode lasting about 1 million years in all. The climate change caused major biodiversity loss in the ocean and on land, but just after the extinction event new groups took over, forming more modern-like ecosystems. The shifts in climate encouraged growth of plant life, and the expansion of modern conifer forests.