Home https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Science https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ The event of the extinction of the Carnian pluvial episode 232 million years is much more severe

The event of the extinction of the Carnian pluvial episode 232 million years is much more severe

The events of mass extinction on our planet have occurred only a few times in the 540 million years since the beginning of life. Most people are familiar with the Cretaceous-Tertiary extinction, which occurred about 65 million years ago, which led to the death of dinosaurs and 50% of all plants and animals, and the Permian-Triassic extinction 250 million years ago, which wiped out 95 percent of all kinds.

But scientists have now reconsidered the impact of the Carnician pluvial episode, a significant climate change event that occurred about 234 to 232 million years ago (late Triassic) that led to the age of the dinosaurs, exploring it with renewed interest. to understand the consequences of severe global changes in the environment and extensive volcanism.

In a new research paper published in the online journal Science Advances and presented by Dr. Mike Benton and Dr. Jacopo Dahl Corso of the University of Bristol at the Chinese University of Geology in Wuhan, the scientists examined all geological and paleontological evidence and made a significant conclusion about what caused this cataclysm.

In their study of the chaotic event, a new analysis of paleontological data shows that the Carnian pluvial episode was a major ̵

1; and previously ignored – period of mass extinction. It can be linked to the extinction of up to a third of all marine genera (invertebrates, vertebrates and protists), including numerous tetrapods, and to the explosive diversification of many important modern groups of plants and animals such as conifers, insects, dinosaurs, crocodiles and lizards. , turtles and mammals.

The strong volcanic eruptions in the province of Wrangel in western Canada are the smoking gun and the most likely cause of the devastation and sudden shift in climate, when abundant amounts of hot volcanic basalt are poured to form much of today’s western North American coast.

“The eruptions peaked in Carnia,” said Dr. Dal Corso. “I studied the geochemical signature of the eruptions a few years ago and found some huge effects on the atmosphere worldwide. The eruptions were so huge, they pumped huge amounts of greenhouse gases like carbon dioxide, and there were peaks in global warming. “

These wet warming periods, lasting a total of one million years, were accompanied by an intense surge in global rainfall, as discovered in the 1980s by geologists Mike Sims and Alastair Ruffel. This gradual climate change is reflected in the great loss of biodiversity in the ocean and on land.

After extinction, however, various new groups flourished to produce more modern ecosystems. These climate changes have been beneficial for the sustainable growth of plant life, especially for the expansion of coniferous forests.

“The new flora probably provides a slim selection of surviving herbivorous reptiles,” explained Professor Benton. “We already know that dinosaurs originated about 20 million years before this event, but they remained quite rare and insignificant until the Carnian Pluvial Episode. The sudden waterless conditions after the wet episode gave the dinosaurs a chance. “

These more hospitable conditions not only allowed dinosaurs to ascend, but also the spread of modern groups of plants and animals, including some early turtles, crocodiles, lizards, and early mammals. The effect of the Carnic pluvial episode on ocean life must also be considered, as it marked the beginning of modern coral reefs and numerous plankton groups, pointing to historical changes in ocean chemistry and the carbonate cycle.

“So far, paleontologists have identified five major mass extinctions in the last 500 million years of life history,” said Dr. Dahl Corso. “Each of them had a strong effect on the evolution of the Earth and life. We have identified another major extinction, and apparently it has played a key role in helping to restore life on land and in the oceans, noting the origins of modern ecosystems. “

Source link