Ancient volcanoes tell a dark story of Earth's future
Wednesday, April 20, 2016, 1:54 PM - Approximately 200 million years ago, well before dinosaurs went extinct, a calamity eradicated a large part of earth’s wildlife.
The most widely attributed cause of this wipe-out is massive volcanic eruptions. Scientists believe these eruptions were triggered when supercontinent Pangea was torn into continents
A recent study co-authored by researchers at University of Southern California (USC) Dornsife develops a stronger argument in favour of that theory. The study notes that volcanic eruptions not only released lava, but also large amounts of carbon dioxide, making a wider statement about how rapid climate change can impact life on earth, Phys.org notes.
The study tracks the drastic escalation of mercury in rock samples preserved from the Triassic-Jurassic extinction period, Phys.org reports.
Unlike the mercury commonly known to exist on earth’s surface, Isotopic data indicates that this mercury can be linked to the eruptions.
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The findings were published by Nature Communications on April 6.
USC professor of earth sciences Frank Corsetti was one of the study’s co-authors, along with fellow earth sciences professor David Bottjer and a team of researchers.
According to Corsetti, the rise in mercury matches changes in earth’s biosphere during that time period.
”As the mercury was found to rise in the rock samples, it matched a wave of animal extinctions on the planet's surface and in its seas,” Phys.org notes. “The mass extinction peaks just as the level of mercury does; biodiversity begins to return once the mercury level recedes, about 700,000 years after the event began.”
Corsetti told Phys.org that the mercury is somewhat of a fingerprint of a massive volcanic eruption in a place known as the Central Atlantic Magmatic Province (CAMP). The publication notes that CAMP was located on the supercontinent of Pangea where the Atlantic Ocean later emerged after the land split.
"If that much material erupted today, it would cover the contiguous United States with about 400 meters of lava—it was an enormous series of eruptions," Corsetti told Phys.org.
The subsequent emission of CO2 has led researchers to believe that CAMP’s appearance might have had something to do with the mass extinction.
"By some estimates, it rose nearly as rapidly as we're putting CO2 into the atmosphere today," Corsetti said to Phys.org. "We wanted to see how the Earth system responded from a rapid rise of CO2. The spoiler alert is that there was a mass extinction. What we've been able to do is use this mercury as a fingerprint to tie the event to the volcanos, and therefore the emissions."
As a result, these ancient volcanoes show the possible impacts of rising CO2 levels. The eerie link, Corsetti points out, is the similarities between present-day climate change and the Triassic-Jurassic extinction – both are preferential in their impact, affecting particularcoral reefs but not all, for example.
Before the Triassic-Jurassic extinction there was the Permian extinction – sometimes referred to as “the mother of all extinctions,” Phys.org notes.
The latter was a much bigger event, though the main organisms impacted were quite different from those commonly affected today.
This fact makes the Triassic-Jurassic cataclysm likely the most pertinent mass extinction to examine when trying to determine the future of the modern world with rising CO2 levels, Corsetti said.