London, March 21 : A new research in the Deccan Traps in India, has suggested that the mass extinction of the dinosaurs at the end of the Cretaceous period may have been caused due to a large release of sulfur and chlorine by volcanic eruptions.
According to a report in New Scientist, the biggest volcanic eruptions are called flood events, which release millions of cubic kilometres of lava and all the gases trapped within it.
One of the main theories about mass extinctions is that such flood events could have pumped sulphur and chlorine into the atmosphere, killing off anything nearby.
"But it's not just poisoning by the pollutants," said Stephen Blake of the Open University in the UK. "There can be a whole lot of knock-on effects to the environment," he added.
However, geologists haven't been sure that enough of the gases were released to effect large-scale climate change, and thus contribute to extinctions.
To investigate that, Blake and his colleagues scoured the Deccan Traps, a region in India that was formed by a flood event about 65 million years ago.
Here, they obtained an inkling of how much sulfur and chlorine gas was released by measuring the gases found inside tiny and rare air bubbles in mineral crystals within Deccan lava rocks.
What they found suggests that the Deccan eruptions could have released from 3.6 to 5.4 teragrams (million metric tons) of sulfur dioxide for every cubic kilometer of lava.
The severe cooling effect of the sulfur, which perhaps struck several times over hundreds of thousands of years and lasted for centuries each time, may have been the real cause of the mass extinction event at the end of the Cretaceous.
"Gases from a series of eruptions of the Deccan Traps may have "battered away" at life on the planet at the time, leading to the mass extinctions," explained geologist Stephen Self of the U.K.'s Open University in Milton Keynes.
"This much sulphur strengthens the case for volcanism to do lots of environmental damage," said Blake.