Major volcanic eruptions may have caused mass extinctions throughout Earth’s history, including the one that wiped out the dinosaurs about 66 million years ago.
Currently, the leading theory to explain the mass extinction that marked the end of the dinosaurs is that it was triggered when asteroid The land influenced what is now the Chicxulub region of the Gulf of Mexico. However, new research suggests that the asteroid may have had a “partner” in this extinction event in the form of volcanic activity.
This new research, which has re-examined volcanic eruptions in terms of the amount of lava emitted, provides the most compelling evidence to date that the relationship between volcanic activity in geological records and the death of multiple species in the blink of a geological eye is not. Coincidence.
“Our results make it difficult to ignore the role of volcanoes in extinction,” said Briannein Keeler, associate professor of Earth sciences at Dartmouth University. statement. (Opens in a new tab)
The fossil record contains the hallmarks of five major mass extinctions, the most famous of which were those of the Cretaceous period – which lasted between 145.5 and 65.5 million years ago – which killed the dinosaurs along with about 76% of all Earth species. .
Keeler and his team found evidence of a type of volcanic footprint called flood basalt that corresponds to the Cretaceous mass extinction and three of the five other mass extinctions recorded in the Earth’s geological record.
Flood basalts leave behind either a series of small volcanic eruptions or a giant one that submerges vast tracts of land with lava. This process creates vast regions of igneous rocks in a gradient-like arrangement called “large igneous provinces” that contain at least 100,000 cubic kilometers of magma.
earth history Already showing evidence of how volcanic eruptions of this magnitude can lead to mass extinctions.
A series of volcanic eruptions in Siberia about 252 million years ago caused one of the most intense mass extinctions ever discovered – the Great Permian Extinction. During these eruptions, massive amounts of carbon dioxide were released into the atmosphere killing 90% of all species and causing an environmental disaster.
Evidence of this violent and destructive volcanic activity has been recorded in the Siberian Trap – a large area of volcanic rock the size of Australia.
At the time of the mass extinction in the Cretaceous period, the Indian subcontinent was hit by volcanic eruptions that created the Deccan Plateau – 7,000 feet (2,000 m) of flat basaltic lava flows covering an area of approximately 190,000 square miles (500,000 square kilometers) in western central India.
Just like the blow to the Chicxulub shockwave, this could have had a far-reaching global impact and could fill Earth’s atmosphere With dust and toxic fumes blocking the sun’s rays, suffocating dinosaurs and other Cretaceous species.
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The true cause of the dinosaurs’ extinction has been hotly debated for some time, but the discovery of the Chicxulub crater in the Gulf of Mexico and the massive impact it made has become a ‘powerful weapon’ dominating all other proposals.
“All the other theories that tried to explain why the dinosaurs were killed spread when the asteroid crater was discovered,” Keeler said. “But there is very little evidence for similar impact events coinciding with other mass extinctions despite decades of exploration.”
In addition to determining the best available estimates of volcanic eruptions, flood basalts with periods of severe species extinction – including but not limited to the five mass extinctionsThe team also randomly generated timelines to test 100 million similar patterns.
They found that less than 1% of the agreed temporal simulations as well as the actual record of basaltic floods and extinctions, suggesting that the relationship between massive volcanic eruptions and mass extinctions is not just a random chance.
These new discoveries may shift the balance in favor of massive volcanic activity, but when it comes to the demise of the Cretaceous period, the team thinks the Deccan Plateau eruption and the Chicxulub impact may have delivered a ‘double punch’ to the survey. outside the dinosaurs.
A detailed paper on the team’s findings has been published in the journal Proceedings of the National Academy of Sciences. (Opens in a new tab)