Study – The new Indian Express

By PTI

LOS ANGELES: The impact of asteroids that swept the dinosaurs from the Earth's surface 66 million years ago may have also rekindled massive volcanic eruptions in India, a half-planet of the impact site , revealed a study.

The research, published in the journal Science, has resulted in more accurate dates for volcanic lava flows from Deccan traps, more closely linking the peak of activity to the impact of asteroids or comets 66 million years ago. years and concomitant mass extinction.

However, it is unclear to what extent the two disasters have contributed to the near-simultaneous mass extinction that has killed dinosaurs and many other life forms.

The research highlights huge lava flows that have periodically erupted over the course of Earth's history, as well as their impact on the atmosphere and on the course of life on the planet.

Scientists at the University of California (UC) Berkeley in the United States have shown that the most accurate and accurate dates to date for intense volcanic eruptions in India that coincided with the global extinction at the end of the Cretaceous, the so-called K-Pg border.

The series of eruptions that lasted a million years has spawned lava flows for a distance of at least 500 kilometers across the Indian continent, thus creating flood basalts of Deccan Traps, with a thickness of nearly two kilometers in places.

"Now that we have dated the Deccan Traps lava flows in more and different places, we see that the transition seems to be the same everywhere," said Paul Renne, of UC Berkeley.

"I would say with considerable confidence that the eruptions occurred in the 50,000 or even 30,000 years of impact, which means that they were synchronous within the margin of error" said Renne.

"This is an important validation of the hypothesis that the impact of renewed lava flows," he said.

The new dates also confirm earlier estimates that lava flows would have continued for about a million years, but contain a surprise: three quarters of the lava erupted after the impact.

Previous studies had suggested that about 80% of the lava had burst before the impact.

While most of the deccan trap lava had exploded before the impact, the gases emitted during the eruptions could have been the cause of global warming during the last 400,000 years of the Cretaceous, during which the temperatures have increased on average by about 8 degrees Celsius.

During this warming period, species would have evolved to adapt to greenhouse conditions, but only to face global cooling of the dust or cooling gases from the climate caused by the impact. or volcanoes.

The cold would have been a shock that most creatures would never have recovered, disappearing entirely from the fossil record.

However, the researchers said that if most of the Deccan Traps lava emerges after the impact, this scenario needs to be rethought.

"This is changing our perspective on the role of Deccan Traps in the extinction of K-Pg," said Courtney Sprain, a former UC Berkeley PhD student.

"Either the Deccan eruptions have not played a role – which we think is unlikely – or a lot of climate-modifying gases have been emitted during the lowest impulse eruptions," said Sprain, currently at the University of Liverpool in Great Britain.