(CN) — While volcanic emissions spewed into the atmosphere have been identified as drivers of mass extinction events in the last half billion years, the most recent one can’t be blamed on volcanism alone, according to a study released Monday.
In the past 500 million years, Earth has experienced five major events with widespread extinction and rapid decrease of biodiversity.
The most recent mass extinction event occurred 66 million years ago at the end of the Cretaceous period.
In that event, a 6-mile wide asteroid smashed into Earth, leaving the Chicxulub crater of the Yucatan Peninsula in its wake.
The asteroid impact sent fire and superheated stone raining down across the Earth which trembled from apocalyptic-level earthquakes that shook the ground with 100 times more power than anything in our recorded history.
Most of the living things that remained after the impact died out after massive particle clouds blocked out the Sun for years.
Researchers have debated whether the force of the asteroid impact alone wiped off three-quarters of living things — including dinosaurs and the flora and fauna from that period — off the face of the planet.
A previous study in the journal Science Advances speculated whether the asteroid impact triggered cataclysmic volcanic eruptions from the Deccan Traps in India, historically one of the most volcanically active regions of the world.
The asteroid impact likely caused underwater volcanic eruptions that drove ocean acidity to deadly levels and triggered an ejection of molten rock that today would cover continental United States with around 200 feet of rock, the study said.
The current study led by researchers at the The Graduate Center at the City University of New York has taken another look at that theory.
Scientists examined clumps of magma trapped in crystalized sediment in the Deccan Traps volcanic province.
They were looking for frozen carbon dioxide samples — along with traces of barium and niobium — that would explain volcanism’s role in shaping climate around the time of the Cretaceous mass extinction event.
Prior research linked mass injection of CO2 into the atmosphere to a global change event several hundred thousand years before the end-Cretaceous extinction. Could another mass eruption after asteroid impact played a role in killing off nearly all remaining life on Earth?
Study author Andres Hernandez Nava of CUNY's Earth and Environmental Science program said in a statement released with the study that researchers sought to fill the gap in CO2 data on Deccan magma.
"Our team analyzed Deccan Traps CO2 budgets that coincided with the warming event, and we found that carbon outgassing from lava volumes alone couldn't have caused that level of global warming," Nava said. "But, when we factored in outgassing from magmas that froze beneath the surface rather than erupting, we found that the Deccan Traps could have released enough CO2 to explain this warming event."
The analysis showed Deccan magma from around the time of Cretaceous extinction had small traces of carbon dioxide; not enough to indicate volcanism’s role in shaping climate around the fifth mass extinction, according to the study published Monday in the journal Proceedings of the National Academy of Sciences.
The study found that CO2 release, or outgassing, could be attributed to an increase of 3 degrees Celsius of Earth's climate around the early phases of Deccan volcanism.
CUNY professor Benjamin Black said in a statement the findings essentially wipe away the theory that volcanism played a major role in driving the most recent mass extinction.
"Our lack of insight into the carbon released by magmas during some of Earth's largest volcanic eruptions has been a critical gap for pinning down the role of volcanic activity in shaping Earth's past climate and extinction events," Black said. "This work brings us closer to understanding the role of magmas in fundamentally shaping our planet's climate, and specifically helps us test the contributions of volcanism and the asteroid impact in the end-Cretaceous mass extinction."
Researchers did not immediately respond to a request for further comment on the study.
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