To Craft a Dinosaur, Start with a Volcano

Some suspect massive volcanic eruptions toward the end of the Mesozoic Era helped spur the extinction of the non-avian dinosaurs after a reign of some 170 million years. Now, it turns out, volcanic eruptions also may have ushered in that reign!

In Proceedings of the National Academy of Sciences, Jason Hilton (University of Birmingham, UK) and a team of Chinese and British colleagues published analyses of lakebed sediments from the Jiyuan Basin of North China laid down between 234 and 232 million years ago. After a dry spell in the early Triassic, Earth experienced a period of global warming— dubbed the Carnian Pluvial Episode—with noticeably intense rainfall and humidity. Examination of sediments revealed carbon isotopes and mercury linked to volcanic eruptions that released massive amounts of carbon dioxide and other atmospheric pollutants. As recorded in the layers of lakebed sediments, there appeared to be four distinct episodes of massive volcanism that may be linked to what is known as the Wrangellia flood basalts in western North America.

The resulting change in global climate is further confirmed by the presence of fossil plant pollens. As you move up those lakebed sediments, you move from plants that thrive in arid environments to those of a more tropical, water-loving nature. At the same time, dinosaurs began to blossom, growing in size and diversity all across Earth to kick off a long and successful reign.