Dinosaurs are in debt to volcanoes, which, thanks to a prolonged period of activity, caused a mass extinction that allowed the reptiles to thrive. A new study found that Triceratops can thank “fire fountains and lava flows” for its one-time existence.
Researchers examined the mercury content of rocks dating from the end of the Triassic period, around 200 million years ago, which preceded the Jurassic period in which dinosaurs became the dominant species on land.
Five of the six samples, sourced from the UK, Austria, Argentina, Greenland, Canada, and Morocco, were found to show a large increase in mercury content at the end of the Triassic period.
Mercury levels can be used to determine the level of volcanic activity at a given time. When eruptions take place, mercury spreads through the atmosphere before being deposited in sediments in the ground.
The intensity of the heightened period of volcanic activity was enough to cause a mass extinction of half the species living on Earth, believed to have been wiped out as the sun became blocked out and carbon dioxide levels rose.
Some of the activity would have lasted over a decade, according to Professor Tamsin Mather from Oxford University, who told the BBC “you likely get eruptive periods going on for a decade or so with enormous volumes of magma coming to the surface and gases as well.”
It is not known why smaller dinosaurs survived the event, paving the way for them to evolve into larger land reptiles that would rule the earth until 65 million years ago.
The latest study shows the period of activity, known as Central Atlantic Magmatic Province (CAMP), occurred globally, adding weight to a 2010 study which showed a spike in carbon dioxide levels at the same period.
The study, from the Oxford University Department of Earth Science in collaboration with the Universities of Exeter and Southampton, is published in the journal PNAS.