(ORDO NEWS) — In the 1970s and 80s, geologists noticed strange layers deposited in ancient rocks dating back to about 232 million years ago.
In the Eastern Alps, one team examined a layer of siliciclastic deposits deposited in carbonate.
Meanwhile, in the UK, geologist and forensic scientist Alastair Ruffell was investigating a layer of gray rock found inside the famous red rock found in the area.
Both of the above discoveries and many more suggested the same thing: About 232 million years ago, the Earth emerged from a dry period and it began to rain.
In fact, given that the gray sandstone and siliceous deposits were deposited over a long, long time, this was evidence that there was an unusually wet period of 1-2 million years at the very beginning of the dinosaur era, when their numbers and diversity skyrocketed.
In fact, since the discovery, there has been growing evidence that the wet period may have been “the trigger that allowed dinosaurs, and possibly other modern land fauna, to diversify and dominate the earth.”
Traces of a period called the Carnian pluvial event have been found by scientists in rocks all over the world.
The reason for the unusual rainfall appears to be the result of a significant increase in humidity, possibly due to a giant volcanic eruption in the Great Wrangel Igneous Province, stretching from south-central Alaska and along the coast of British Columbia.
“The eruptions peaked in the Carnians,” said study participant Jacopo Dal Corso.
“Several years ago, I studied the geochemical signature of eruptions and found some serious effects on the atmosphere around the world.
The eruptions were so huge that huge amounts of greenhouse gases were emitted and there were bursts of global warming.”
The supercontinent Pangea was already subject to monsoons at that time. They occur when moisture-laden air from the seas blows towards land, where it cools and falls as heavy rains.
As the seas warmed during this period, reaching hot soup temperatures, paleoecologist Paul Wignall told New Scientist, there would have been more moisture over Pangea, leading to more monsoons and heavier precipitation on land.
However, this wet period was not favorable for life. A study published in the Journal of the Geological Society describes that at that time, “volcanic eruptions produced acid rain and greenhouse gases, which in turn led to extinction as a result of severe warming, the destruction of vegetation and soils on land, as well as anoxia and ocean acidification.
Many species died as a result of this event.
“As a result of the mass extinction of plants and key herbivores on land, dinosaurs appear to have been the main beneficiaries during the recovery, rapidly expanding in diversity, ecological impact and regional distribution, initially from South America to all continents,” the team of researchers wrote.
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