Climate change helped some dinosaurs migrate to Greenland

Climate change helped some dinosaurs migrate to Greenland


2021-03-22 21:25:41

The drop in carbon dioxide levels may have helped Sauropodomorphs, the first cousin of the largest animal to ever roam on Earth, migrating thousands of kilometers north across deserts some 214 million years ago. Scientists have timed the dinosaurs’ journey from South America to Greenland by correlating the rock layers with the Sauropodomorph fossil with changes in the Earth’s magnetic field.

Using that timeline, the team found that the northerly push of the organisms coincided with a significant reduction in CO2, which may have eliminated climate-related barriers. is a group of long-necked, plant-eating dinosaurs that consisted of the giant Sauropod and Seismosaurus. About 230 million years ago, Sauropodomorphs lived mainly in what is today northern Argentina and southern Brazil.

Late Triassic vertebrate fossils have been found at several locations around the world, some marked (black dots) on this map showing how continents were arranged around 220 years ago. million years. Dating rocks at sites in South America and Greenland is an accurate method of determining the time period when Sauropodomorphs migrated north.

But at some point, these primitive dinosaurs had moved as far north and to Greenland, but the exact moment they made that journey was a riddle. “In principle, you can walk from where they live to the other hemisphere, 10,000 kilometers away,” said Dennis Kent, a geologist at Columbia University. At that time, Greenland and the Americas had merged into the Pangea supercontinent and had no oceans in their way. If the dinosaurs were walking at a slow speed of 1 to 2 kilometers per day, it would take them about 20 years to get to Greenland ”.

But for much of the Late Triassic, which lasted between 233 million and 215 million years ago, Earth’s carbon dioxide levels were incredibly high – to 4,000 parts per million (mean CO2 levels today are around 415 parts per million). . Climate simulations have suggested that CO2 levels will create super arid deserts and extreme climatic fluctuations and form barriers to giant monsters. With vast deserts stretching north and south of the equator, there will be very few species of plants available to herbivores that can survive on their journey north most of the time. there.

Previous estimates suggest these dinosaurs migrated to Greenland between 225 million and 205 million years ago. To get more accurate dating, Kent and his colleagues measured magnetic samples in ancient rocks in South America, Arizona, New Jersey, Europe and Greenland – all local where the fossils are located. Sauropodomorph has been discovered.These samples record the direction of the Earth’s magnetic field at the time of rock formation.

Climate change helped some dinosaurs migrate to Greenland - Photo 2.

Sauropodomorphs were a long-necked, plant-eating branch of dinosaurs that consisted of Sauropoda and their relatives. Sauropods usually grow to large sizes, have a long neck and tail, walk on all fours, and become the largest group of animals ever to stand on Earth. “Prosauropoda”, was a pre-evolution of Sauropoda, their size was smaller and they sometimes even walked on their hind legs. Sauropodomorphs were once a group of herbivorous dinosaurs that dominated the Earth in the Mesozoic, but then declined and went extinct by the end of the Cretaceous (about 66 million years ago).

By comparing those patterns to previously excavated rocks, the team found that Sauropodomorph appeared in Greenland about 214 million years ago. Greenland, carbon dioxide levels have plummeted within a few million years, to 2,000 parts per million, making the climate more herbivore friendly.

The reason for this drop in carbon dioxide – which appears in climatic profiles from South America and Greenland – is unknown, but it allows for a favorable exodus north.

“We have evidence for all of these events, but the temporal consolidation is the remarkable thing here,” said Morgan Schaller, a geochemist at the Rensselaer Polytechnic Institute. “These new findings also help solve the mystery why this giant plant-eating dinosaur was moving around a time when predators were still roaming freely.”

Steve Brusatte, paleontologist and evolutionary biologist at the University of Edinburgh, said: “This research reminds us that we cannot understand evolution without understanding climate and the environment. “Even the greatest and most wonderful creatures that ever lived are still controlled by the unusual changes of the climate.”

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