Fossil Tracks Suggest Dinosaurs Lived in a "Land of Fire"

Saturday, February 1, 2020

Reconstruction of the environment set alight by a volcanic flowBordy et al, 2020

A new study has found dinosaur footprints in sandstone embedded between fossilized lava dating back 183 million years in southern Africa. During this time in the early Jurassic period, a mass extinction was taking place and parts of the world were being transformed into a world of fire by rampant volcanism.

Extinction events permeate our planet’s history. One of the most famous of these events is the devastating asteroid strike that occurred 66 million years ago, and brought about the extinction of non-avian dinosaur species.

Whilst this impact ended the reign of the dinosaurs, it was by no means the first mass extinction that was inflicted upon them. A new study has identified dinosaur prints dating back to 183 million years to the early Jurassic period, when volcanic eruptions were dramatically changing the face of the world, along with its climate.

The fossils studied by the researchers were discovered in the Karoo Basin in southern Africa, which is known for harboring massive deposits of igneous rock. These deposits are what remains of lava flows which, over time, fundamentally altered vast swathes of the ancient African terrain.

Five sets of fossilized tracks made up from a total of 25 footprints were discovered in sandstone deposited between lava flows. This suggests that the creatures that made the prints survived the first bout of volcanic eruptions that, the paper describes, would eventually turn their homes into a "land of fire."

Based on the length of the footprints – between 2 to 14 cm (0.8 to 5.5 in) – and the patterns in the trackways, the researchers believe that the marks were made by three types of animals: small mammals or their precursors, small four-legged herbivores, and a group of large bipedal carnivores. The patterns suggested that some of the dinosaurs had been running when they made the prints.

According to the authors of the study, these creatures were likely some of the last to inhabit the Karoo Basin before it was consumed by lava flows.

"The fossil footprints were discovered within a thick pile of ancient basaltic lava flows that are 183 million years old," comments one of the study’s authors, Emese M. Brody of the University of Cape Town. "The fossil tracks tell a story from our deep past on how continental ecosystems could co-exist with truly giant volcanic events that can only be studied from the geological record, because they do not have modern equivalents, although they can occur in the future of the Earth."

The study has been published in the journal PLOS ONE.

Source: PLOS via EurekAlert