Tyrannosaurus rex: Expert examines brain of dinosaur
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A new study by researchers at the University of Birmingham has identified the environmental conditions that aided the dinosaurs’ accent more than 230 million years ago. Prior to the so-called Late Triassic Carnian Pluvial Episode (CPE), when the continents were arranged into a single supercontinent dubbed Pangea, the land was much drier and less-welcoming than it is today. But all of that changed some 234 million to 232 million years ago when conditions became warmer and wetter, likely as a result of intense volcanism.
The international team based in Birmingham came to this conclusion after analysing fossils and sediments collected in a lake in northern China’s Jiyuan Basin.
The researchers matched their findings to “pulses of volcanic activity” that helped drive an increase in global temperatures and humidity.
The findings also happened to coincide with the Pangean megamonsoon, which helped plant and animal life diversify and thrive.
Modern conifers, for instance, appeared during this period.
According to Jason Hilton, Professor of Palaeobotany and Palaeoenvironments at the University of Birmingham’s School of Geography, Earth and Environmental Science, the volcanic activity that drove these drastic changes was unlike anything humans have ever witnessed.
He told Express.co.uk: “This would have been much larger than anything seen on Earth in human history.
“The Eyjafjallajokull eruptions in Iceland of more than a decade ago that affected flying on much of the globe would have paled into insignificance compared to Wrangellia.”
The research team identified four distinct episodes of volcanic activity during the CPE, with the most likely source in the Wrangellia Large Igneous Province.
Remnants of this tectonic feature, including the Wrangell Mountains in Alaska, are still found in western North America.
The volcanoes would have pumped large amounts of carbon dioxide (CO2) and other greenhouse gasses into the atmosphere, triggering a greenhouse effect.
Dinosaurs: Fossil shows 'different appearance' says expert
The CO2 drive global temperatures up and introduced much more rain.
And within the space of just two million years, the diversity of animal and plant life went through a dramatic change.
Professor Hilton said: “We can’t say what might have been different, but clearly the climate and environment changes that occurred during the Carnian Pluvial Episode were sufficient to change the vegetation in parts of the world a great distance from Wrangellian volcanism.
“As the vegetation changed, there would have been knock on consequences for other organisms in terrestrial and aquatic ecosystems including herbivorous animals.
“They had to adapt to the available sources of food, or die.”
The researchers found that each of the four pulses coincided with disturbances in the global carbon cycle, more humid conditions, as well a decrease in oxygen in the Chinese lake.
Geological events on a similar time frame have also been recorded in Central Europe, North America, East Greenland, Argentina and Morocco.
The findings indicate an increase in rainfall led to the expansion of drainage basins merging into swamps and lakes, rather than rivers and oceans.
According to Dr Emma Dunne, a Palaeobiologist also at the University of Birmingham, who was not involved in the study, this period would have had “considerable consequences for animals on land”.
Dinosaurs had just begun to diversify and “it’s likely that without this event, they would never have reached their ecological dominance we see over the next 150 million years”.
However impressive the volcanic activity may have been 230 million years ago, Professor Hilton said modern-day global warming has already surpassed anything seen in the past.
He said: “Global warming is a natural phenomenon following large scale volcanism, but the present rate of global warming surpasses anything seen in the geological record.
“Many of the features we see in mass extinctions in the geological record are happening around us now as a result of anthropogenic climate change including extreme temperatures, changes in rainfall patterns, increased aridity and widespread wildfires.”
The study was published in the journal Proceedings of the National Academy of Sciences.
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