Dinosaurs Erupt into Dominance?

New Evidence that Volcanic Eruptions Triggered the Dawn of the Dinosaurs

This article, from researchers at Oxford, suggests that the Triassic–Jurassic extinction event may have been caused by volcanic gases released during the volcanic activity of the Central Atlantic Magmatic Province (CAMP). 

A photo I took of CAMP volcanics (the dark rocks at the top of the cliff) at Five Island Provincial Park, on the Bay of Fundy in September 2009

There is some doubt whether the volcanism occurred at the same time as the extinction. So the researchers decided to look for a “fingerprint” of the eruptions in the same kind of sediments that record the mass extinction. And the fingerprint used was mercury.

They investigated six sedimentary records of the end-Triassic extinction for mercury concentrations. These records were from the UK, Austria, Argentina, Greenland, Canada and Morocco. They found that five of the six records showed a large increase in mercury content beginning at the end of the Triassic period, with a distinct spike in mercury at the layer corresponding to the extinction itself. 

More importantly, they were able to show the elevated mercury emissions matched previously established increases in the amount of CO2 in the atmosphere. This strongly supports the theory that the CO2 emissions thought to cause the end-Triassic extinction came from volcanoes.