A new study has revealed how the rise of dinosaurs over 230 million years ago coincided with environmental changes brought on by massive volcanic eruptions.
Known as the Carnian Rainfall of the Late Triassic (CEP), this interval of enormous climate change has seen temperatures and humidity rise across the globe.
Prior to CPE, the climate of the Pangea supercontinent is believed to have been generally arid, but during this time it became humid and ripe for life.
A team of researchers, including experts based at the University of Birmingham, analyzed the records of sediment and fossil plants from a lake in the Jiyuan Basin in northern China.
They found that these recordings showed a correlation between “pulses of volcanic activity with significant environmental changes,” including the CEP’s “mega monsoon” climate.
Their findings are published in the Proceedings of the National Academy of Sciences and detail four distinct episodes of volcanic activity, including major eruptions from the large igneous province of Wrangellia.
Also known as the Wrangellia Terrane, after the Wrangell Mountains in Alaska, this fragment of tectonic crust is believed to have been the source of the enormous volcanism that altered the Earth’s climate around 230 million years ago. years.
The main cause of this climate change has been the introduction of huge amounts of carbon dioxide into the atmosphere and the ocean during this period.
The increase in the volume of CO2 in the atmosphere has led to global warming and, as such, accelerated the hydrological cycle, which means a lot more rain.
Professor Jason Hilton, co-author of the study and an expert in paleobotany and paleoenvironments at the University of Birmingham, explained the results.
âIn the space of two million years, the animal and plant life of the world has undergone major changes, including selective extinctions in the marine realm and the diversification of groups of plants and animals on land.
“These events coincide with a remarkable interval of intense precipitation known as the Carnian rainfall event,” said the professor.
“Our research shows, in a detailed recording from a lake in northern China, that this period can in fact be resolved into four separate events, each driven by discrete pulses of powerful volcanic activity coupled with huge releases. of carbon dioxide in the atmosphere. These triggered an increase in global temperature and humidity. “
Evidence of major climate change was also found in Central Europe, East Greenland, Morocco, North America and Argentina, and revealed that increased rainfall from the CEP led to the convergence of the Pangea watersheds. in lakes and swamps rather than rivers or oceans.
“Our results show that large volcanic eruptions can occur in several discrete pulses – demonstrating their potent ability to alter the global carbon cycle, cause climatic and hydrological disturbances, and drive evolutionary processes,” the co-author added. , Dr Sarah Greene.
Dr Emma Dunne, a paleobiologist at the University of Birmingham who was not involved in the study, commented: âThis relatively long period of volcanic activity and environmental change would have had far-reaching consequences for terrestrial animals.
“At that time, dinosaurs were just starting to diversify, and it is likely that without this event they would never have achieved their ecological dominance that we see in the next 150 million years,” said Dr Dunne.
Professor Hilton added: âIn addition to dinosaurs, this remarkable period in Earth’s history has also been important for the development of modern conifer groups and has had a major impact on the evolution of terrestrial ecosystems and animal and plant life – including ferns, crocodiles, turtles, insects and early mammals. “