The most dramatic part of the largest mass extinction our planet has ever witnessed happened just over 252 million years ago – and lasted no more than 200,000 years.

This an international research team concludes based on investigation of late Permian sediments in southern China.

Their research tries to answer a few important questions concerning the Permian-Triassic mass extinction, during which a staggering 70 percent of terrestrial life and 95 percent of marine species were wiped out. As the researchers write in last week’s edition of Science the biodiversity crisis happened simultaneously on land and in the oceans – and most extinctions occurred in a time frame of just 20,000 years. [The kill may have been swift, the rebirth was not. Other research shows the ecological damage of the mass extinction lasted millions of years into the Triassic.]

The researchers think a rapid carbon rise at the end-Permian was the initial trigger: “A massive release of thermogenic carbon dioxide and/or methane may have caused the catastrophic extinction” – the period coincides with the formation of the Siberian traps, testimony of massive flood basalt and other volcanic eruptions that occurred in what is now northern Russia.

Uncertainties remain about the specific kill mechanisms, which were likely many – and which included [next to for instance ocean anoxia] massive wildfires, as shown by charcoal-rich and soot-bearing layers that were also found in the Chinese sediments. [The massive end-Permian forest die-off was helped about by climate-induced microbial plagues, another recent publication shows.]

© Rolf Schuttenhelm | www.bitsofscience.org