Dinosaurs found success after extinction event 232 million years ago

Dinosaurs dominated the landscape of our planet for millions of years, until they were wiped out when a huge asteroid plummeted to Earth.

Now, scientists say that the creatures may have begun to thrive thanks to a similarly sized extinction event.

More than 200 million years ago most of the life on Earth was destroyed in a mass extinction caused by a dramatic shift in the carbon cycle.

This event, which scientists say was caused by a series of massive volcanic eruptions, led to a period of climate change over millions of years.

Experts believe this provided an ideal opportunity for dinosaurs to take over, replacing the animals which roamed the planet before them.

 

More than 200 million years ago most life on Earth was destroyed. The Carnian Pluvial Episode provided an opportunity for dinosaurs to thrive and saw a surge in their population numbers worldwide, researchers say. This image shows an artist’s impression of the killer reptiles

In a new study, an international team of scientists found that the key expansion of dinosaurs was triggered by the Carnian Pluvial Episode, which occurred around 232 million years ago.

Although the enormous reptiles were around from the beginning of the Triassic Period, some 245 million years ago, they were relatively rare at this point in history.

The shock events of the mass extinction event 13 million years later gave them an opportunity to blossom.

Over this period, the climate altered from dry to humid and back to dry again, destroying almost all of life on Earth and leading to the diversification of dinosaurs, they say.

Researchers made the discovery by looking at when dinosaurs rose to dominance by looking at evidence from rock sequences in the Dolomites, a mountain range in north Italy.

The team found a series of footprints buried in layers of stone. They revealed the history of the expansion of the creatures, with a proliferation of the tracks as time went on.

Experts say this allowed them to pinpoint the moment of the dinosaur explosion, which they dated by establishing the point in geological history indicated by the strata of rocks in which they were found.

Researchers dated the earliest dinosaur skeletons and footprints to around the time of the mass-extinction event at several spots around the world, including Italy and Argentina (stock image)

Researchers dated the earliest dinosaur skeletons and footprints to around the time of the mass-extinction event at several spots around the world, including Italy and Argentina (stock image)

Comparison with rock layers in Argentina and Brazil, where the first extensive skeletons of dinosaurs occur, show the explosion happened at the same time there.

This suggests a global trend as dinosaurs arose across the planet as the most successful form of life. 

Lead author Dr Massimo Bernardi, Curator at Muse and research associate at Bristol’s school of Earth sciences, said: ‘We were excited to see that the footprints and skeletons told the same story.

‘We had been studying the footprints in the Dolomites for some time, and it’s amazing how clear cut the change from “no dinosaurs” to “all dinosaurs” was.’

It was long suspected that this event had caused upheavals among life on land and in the sea, but the details were not clear.  

Then, in 2015, dating of rock sections and measurement of oxygen and carbon values showed just what had happened. 

Dinosaurs and other reptiles dominated Earth for hundreds of millions of years until they were made extinct. They lived in all environments on pre-historic Earth and their origin has remained a long-standing mystery. This image shows a reconstruction a giant marine reptile

Dinosaurs and other reptiles dominated Earth for hundreds of millions of years until they were made extinct. They lived in all environments on pre-historic Earth and their origin has remained a long-standing mystery. This image shows a reconstruction a giant marine reptile

They revealed massive eruptions in western Canada, represented today by the great Wrangellia basalts.

These drove bursts of global warming, acid rain, as well as mass killing on land and in the oceans.

Co-author Piero Gianolla, from the University of Ferrara, added: ‘We had detected evidence for the climate change in the Dolomites. There were four pulses of warming and climate perturbation, all within a million years or so. This must have led to repeated extinctions.’

Professor Mike Benton, also a co-author, from the University of Bristol, said: ‘The discovery of the existence of a link between the first diversification of dinosaurs and a global mass extinction is important.

‘The extinction didn’t just clear the way for the age of the dinosaurs, but also for the origins of many modern groups, including lizards, crocodiles, turtles, and mammals – key land animals today.’  

The research was published in the journal Nature Communications. 

Researchers looked at when dinosaurs became dominant by looking at evidence from rock sequences in the Dolomites mountain range, in north Italy

Researchers looked at when dinosaurs became dominant by looking at evidence from rock sequences in the Dolomites mountain range, in north Italy

WHEN WERE EARTH’S ‘BIG FIVE’ EXTINCTION EVENTS?

Traditionally, scientists have referred to the ‘Big Five’ mass extinctions, including perhaps the most famous mass extinction triggered by a meteorite impact that brought about the end of the dinosaurs 66 million years ago. 

But the other major mass extinctions were caused by phenomena originating entirely on Earth, and while they are less well known, we may learn something from exploring them that could shed light on our current environmental crises.

  1. The Late Ordovician This ancient crisis around 445m years ago saw two major waves of extinction, both caused by climate change associated with the advance and retreat of ice sheets in the southern hemisphere. This makes it the only major extinction to be linked to global cooling. 
  2. The Late Devonian: This period is now regarded as a number of ‘pulses’ of extinction spread over 20m years, beginning 380m years ago. This extinction has been linked to major climate change, possibly caused by an eruption of the volcanic Viluy Traps area in modern-day Siberia. A major eruption might have caused rapid fluctations in sea levels and reduced oxygen levels in the oceans.
  3. The Middle Permian:  Scientists have recently discovered another event 262m years ago that rivals the ‘Big Five’ in size. This event coincided with the Emeishan eruption in what’s now China, and is known to have caused simultaneous extinctions in the tropics and higher latitudes.
  4. The Late Permian: The Late Permian mass extinction around 252m years ago dwarfs all the other events, with about 96% of species becoming extinct. The extinction was triggered by a vast eruption of the Siberian Traps, a gigantic and prolonged volcanic event that covered much of modern day Siberia, which led to a cascade of environmental effects.
  5. The Late Triassic: The Late Triassic event, 201m years ago, shares a number of similarities with the Late Permian event. It was caused by another large-scale eruption, this time of the Central Atlantic Magmatic Province, which heralded the splitting of the supercontinent Pangaea and the initial opening of what would later become the Atlantic Ocean.



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