A volcanic eruption that lasted a million years and flooded Siberia with mile-deep lava may have killed 80% of the world's animals--an extinction far more deadly than the later one that claimed the dinosaurs, researchers concluded.
Precise dating of geologic samples that mark the extinction 250 million years ago show that the massive die-off occurred about the same time a volcanic eruption blanketed Siberia with lava and filled the global sky with chemicals, scientists report today in the journal Science.
"We have been able to put a very precise date on the extinction boundary [formation], something that has not been done before," said Mark Richards, a UC Berkeley professor of geophysics and co-author of the study.
The date of that extinction, which marks the shift from the Permian to Triassic period, was the same, within a few thousand years, as the Siberian eruptions. Richard said basalt lava poured out of fissures in Siberia and flowed like scorching cookie dough across thousands of square miles. Up to a cubic mile of lava belched out annually for about a million years, he said.