Triassic Boundary

25 Mar 2010

www.physorg.com/print188488094.html March 22nd ... 200 million years ago most land on the planet was consolidated into a single continent - Pangea. There was no Atlantic Ocean and the animal world was dominated by creatures related to modern crocodiles. Their world was transformed after what appears to have been a huge catastrophe involving massive and widespread volcanic activity which in turn led to a spike in atmospheric greenhouse gases that wiped out half of the plant species and brought the Triassic to an end. What actually triggered the volcanic activity and destruction of the biomass is unknown but it decimated the crurotarean population (crocodilia) which previously had to compete vigorously with early dinosaurs and dominated them. As such, small dinosaurs were freed from their competitors and developed into the dinosaurs of popular culture. Scientists now know that at 200 million years ago Pangea was split apart and the Atlantic was formed as fissures clawed the two sides apart. Flows of lava in geological beds on both sides of the Atlantic are evidence of the rift. The incredible thing is that researchers were able to home in on rift geology to analyse fossils and carbon signatures from ancient basins in NE America and Britain where they found evidence of fossilised sediments from lakes that dotted Pangea before the separation of the two plates. Wonderful.