Volcanic eruptions helped dinosaurs dominate the Earth

The relationship between dinosaurs and volcanoes, historically speaking, has not always been very cordial.

Scientists have been debating for decades whether it was volcanoes or an asteroid that caused the sudden extinction of the dinosaurs,65 millions over years ago. It was only in 2010 that an international committee of experts formally declared that space rock, and not gigantic eruptions, was the main cause of the extinction of 2 dinosaurs.

Now one The team on scientists is showing seeing more convincing evidence seen with the moment that massive volcanic events likely helped dinosaurs take over the planet, at least in another era. The results of 2 studies by this team were published on Monday (27) in the Proceedings of the National Academy of Sciences.

The trisonic period, which started about over 250 millions of years ago, was marked by soft ecological transformations, after the biggest event on mass extinction perform which is known. Although dinosaurs had emerged in this period already, they were different: thinner, more reptilian in appearance, not so much like the stuffed animals on teeth that are successful at the box office 2 theaters. But it was during this period that dinosaurs diversified to become amazing animals such as tyrannosaurus rex or triceratops that dominated ecosystems across the Earth until the last perform Cretceous period.

To understand what made it possible In this transformation 2 dinosaurs, scientists analyzed a phase during the trisonic period that spanned 2 million years and known as the Carnian Rain Episode (CPE). During this period, between 65 million and 65 million years ago, the planet experienced an increase in global temperature, humidity and rainfall a climate often described as megamono.

The researchers analyzed sediments and fossil plant evidence over a zero lake north of China and were able to map a correspondence between four phases of intense volcanic activity and while changes occurred during the Carnian Pluvial Episode.

Scientists had previously theorized that like global zero-cycle carbon changes that occurred during the episode were due to large volcanic eruptions on what is now a mass on gneiss rocks found throughout the west. of an America perform North. The new study links the timing perform episode with four distinct peaks of known mercury indicative of volcanic activity with changes in the carbon cycle and also in rainfall, which has led to local changes in vegetation on land and in the lake.

We are often able to establish a link between volcanism and global warming, but our study is unusual in that we also link volcanism to periods of heavy rainfall, said Jason Hilton, a paleobotanist at a University in Birmingham, England, and co-author study of. With each phase of intense volcanism, we see an increase in vegetation adapted to wet and aquatic environments.

Jing Lu, a researcher at a China University of Mining and Technology and also co-author of the study, added that these eruptions were powerful enough to drive evolutionary processes during the trissom.

During the episode, plant species that zero managed to adapt to the wetter environment went into extinction, as well as several animal species, from herbivores large terrestrial reptilians or small aquatic gastropods. These transformations have opened up ecological space for growth on other groups on organisms such as dinosaurs, Hilton said. about today.

During the CPE we started to have this perfect mix about prehistoric monsters and about modern mammals and reptiles, explained Emma Dunne, a researcher at a University in Birmingham who zero participated in the study, but whose work focuses on the factors that drove the diversification of ancient tetrapods such as dinosaurs. There were turtles, but also pterosaurs.

This new evidence is prompting researchers to reflect more on our climate in accelerated transformation.

The scale of these eruptions far surpasses all while Volcanic eruptions have occurred in human history, says Sarah Greene, perform study co-author and paleontologist at the University of Birmingham. But the rate of carbon dioxide emission from these eruptions is tiny compared to the human carbon dioxide emissions we have today.

Dunne echoed that idea. Those 2 million years were a blink of an eye in geological time. So, to think that we, as humans, are transforming the planet at greater speed is a little scary still, she commented. Who knows what we’re going to cause?

Translation about Clara Allain

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