Combined impacts of volcanic eruptions in India and an asteroid impact in Mexico brought about one of the Earth's biggest mass extinctions that wiped out the dinosaurs 66 million years ago, confirms a new study.
"It's quite likely both the volcanism and the asteroid were to blame for the ultimate mass extinction," said one of the researchers, Andrea Dutton from the University of Florida.
"The Deccan Traps weakened the ecosystems before the asteroid slammed into the Earth -- it's consistent with an idea called the press-pulse hypothesis: a 'one-two punch' that proved devastating for life on Earth," Dutton noted.
Located in India, the Deccan Traps are one of the largest volcanic provinces in the world.
Dutton and her colleagues at the University of Michigan utilised a new technique of analysis to reconstruct Antarctic Ocean temperatures that support the idea that the combined impacts of volcanic eruptions and an asteroid impact brought about the mass extinctions 66 million years ago.
Their research, published in the journal Nature Communications, used a recently developed technique called the carbonate clumped isotope paleothermometer to analyse the chemical composition of fossil shells in the Antarctic Ocean.
This analysis showed that ocean temperatures rose significantly.
The researchers linked these findings to two previously documented warming events that occurred near the end of the Cretaceous Period - one related to volcanic eruptions in India, and the other, tied to the impact of an asteroid or comet on the Yucatan Peninsula in Mexico.
To create their new temperature record, which spans 3.5 million years at the end of the Cretaceous and the start of the Paleogene Period, the researchers analysed the isotopic composition of 29 remarkably well-preserved shells of clam-like bivalves collected on Antarctica's Seymour Island.
The data showed two significant temperature spikes.
The first corresponds to the eruption of the Deccan traps flood basalts. The other lines up exactly with the asteroid impact, which, in turn, may have sparked a renewed phase of volcanism in India.
Intriguingly, both events are associated with extinction events of nearly equal magnitude on Seymour Island, Antarctica, the study said.
--IANS
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