Subsurface magma intrusions (sills), rather than surface lava flows, may have triggered the Earth’s most catastrophic extinction event approximately 252 million years ago. (more…)
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Washington, D.C.— Around 250 million years ago, at the end of the Permian period, there was a mass extinction so severe that it remains the most traumatic known species die-off in Earth’s history. Some researchers have suggested that this extinction was triggered by contemporaneous volcanic eruptions in Siberia. New results from a team including Director of Carnegie’s Department of Terrestrial Magnetism Linda Elkins-Tanton show that the atmospheric effects of these eruptions could have been devastating. Their work is published in Geology.
The mass extinction included the sudden loss of more than 90 percent of marine species and more than 70 percent of terrestrial species and set the stage for the rise of the dinosaurs. The fossil record suggests that ecological diversity did not fully recover until several million years after the main pulse of the extinction. (more…)
*Few parallels for today’s rapid ocean changes in geologic record*
The oceans may be acidifying faster today than they did in the last 300 million years, according to scientists publishing a paper this week in the journal Science.
“What we’re doing today really stands out in the geologic record,” says lead author Bärbel Hönisch, a paleoceanographer at Columbia University’s Lamont-Doherty Earth Observatory. (more…)
*In “The Great Dying” 250 million years ago, the end came slowly*
The deadliest mass extinction of all took a long time to kill 90 percent of Earth’s marine life–and it killed in stages–according to a newly published report.
It shows that mass extinctions need not be sudden events.
Thomas Algeo, a geologist at the University of Cincinnati, and 13 colleagues have produced a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic. (more…)