Volcanism heralded dinosaur era?

Oxford study says mass extinction after volcanic eruption about 200 mn years ago helped the reptiles

Volcanic activity may have played a key role in triggering the mass extinction event about 200 million years ago, which set the scene for the rise and age of the dinosaurs, an Oxford study has found.

The Triassic extinction, one of the largest mass extinctions of animal life on record, was proceeded by the dinosaur era. The casualty list includes large crocodile-like reptiles and several marine invertebrates.

While it remains a mystery why the dinosaurs survived this event, they went on to fill the vacancies left by the now extinct wildlife species, alongside early mammals and amphibians.

This mass extinction has long been linked to a large and abrupt release of carbon dioxide into the atmosphere, but the exact source of this emission has been unknown.

Following the discovery of volcanic rocks of the same age as the extinction, volcanic carbon dioxide emissions had previously been suggested as an important contributor to this extinction event.

Previous studies have also shown that this volcanism might have occurred in pulses, but the global extent and potential impact of these volcanic episodes has remained unknown.

Link to Triassic period

These volcanic rocks covered a huge area, across four continents, representing the Central Atlantic Magmatic Province.

Researchers from the Oxford University in collaboration with the Universities of Exeter and Southampton in the U.K. traced the global impact of major volcanic gas emissions and their link to the end of the Triassic period.

The findings of the study link volcanism to the previously observed repeated large emissions of carbon dioxide that had a profound impact on the global climate, causing the mass extinction at the end of the Triassic Period, as well as slowing the recovery of animal life afterwards.