[Rockhounds] Scientists zero in on the role of volcanoes in the demise of dinosaurs

[Kreigh Tomaszewski]

Earth has experienced five major mass extinction events over the past 500
million years. Massive volcanic eruptions have been identified as the major
driver of the environmental changes that precipitated at least three of
these extinction events. The fifth and most recent event—the end-Cretaceous
mass extinction—occurred 66 million years ago and was responsible for
wiping out dinosaurs. Researchers have long debated whether gas emissions
from volcanic eruptions from the Deccan Traps (an enormous volcanic
province located in India) or the impact of a large asteroid is most
responsible for causing the climate changes that triggered that event. Now,
a multi-institutional research team led by scientists from The Graduate
Center, CUNY has analyzed the amount and timing of CO2 outgassing (one of
the main gases released by the Deccan Traps) to further determine the role
that volcanism played in climate shifts around the time of the
end-Cretaceous mass extinction.

Recent research has identified a global warming event that occurred several
hundred thousand years before the end-Cretaceous extinction. Some
scientists have linked the eruption of the Deccan Traps to this warming
event, but there is debate over whether the lavas that erupted could have
released enough CO2 into the atmosphere to cause it. Adding to this
mystery, the lava volumes that erupted during this time are relatively
small compared to the volumes erupted during subsequent stages of Deccan
Traps activity. A major challenge in this debate has been the lack of CO2 data
on Deccan magmas from this time.

"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," said Andres Hernandez Nava, a
Ph.D. student in The Graduate Center, CUNY's Earth and Environmental
Science program and first author of a newly published paper in the *Proceedings
of the National Academy of Sciences* journal detailing new findings about
this event. "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."

https://phys.org/news/2021-03-scientists-role-volcanoes-demise-dinosaurs.html