CO2 Dip May Have Helped Dinosaurs Walk From South America to Greenland
A new paper refines estimates of when herbivorous dinosaurs must have traversed North America on a northerly trek to reach Greenland, and points out an intriguing climatic phenomenon that may have helped them along the journey.
The study, published today in Proceedings of the National Academy of Sciences, is authored by Dennis Kent, adjunct research scientist at Columbia University’s Lamont-Doherty Earth Observatory, and Lars Clemmensen from the University of Copenhagen.
Previous estimates suggested that sauropodomorphs — a group of long-necked, herbivorous dinosaurs that eventually included Brontosaurus and Brachiosaurus — arrived in Greenland sometime between 225 and 205 million years ago. But by painstakingly matching up ancient magnetism patterns in rock layers at fossil sites across South America, Arizona, New Jersey, Europe and Greenland, the new study offers a more precise estimate: It suggests that sauropodomorphs showed up in what is now Greenland around 214 million years ago. At the time, the continents were all joined together, forming the supercontinent Pangea.
With this new and more precise estimate, the authors faced another question. Fossil records show that sauropodomorph dinosaurs first appeared in Argentina and Brazil about 230 million years ago. So why did it take them so long to expand into the Northern Hemisphere?
Please, to access the full article visit Columbia University