Asteroid or supervolcano? New study says dinosaurs were wiped out by BOTH
- ‘Volcanic winters’ weakened the dinosaurs for 200,000 years prior to extinction
- ‘The final blow,’ researchers said, was likely given by Chicxulub meteor impact
- READ MORE: T.Rex had the same number of brain neurons as modern primates and may have been capable of problem-solving and even culture, study claims
Repeated ‘volcanic winters’ may have left the dinosaurs hungry, shivering and vulnerable to a fatal ‘final blow’ by the asteroid that ultimately did them in.
At least, an international team of researchers from Italy, Norway, Canada and the US has reached that conclusion in a new study, which analyzed sulfur and fluorine gases trapped in ancient volcanic rocks from the infamous Deccan Traps supervolcano.
This sulfur and fluorine — belched out by the Deccan Traps over 200,000 years before the extinction-level event — would have dropped global temperatures by as much as 18 degrees Fahrenheit (10 degrees Celsius), their new study determined.
The findings add further clarity to the raging debate between paleontologists and other scientists over what actually drove the dinosaurs to extinction.
Their work aligns itself with a compromise theory: the ‘press-pulse extinction model.’
Repeated ‘volcanic winters’ may have left the dinosaurs hungry, shivering and vulnerable to a fatal ‘final blow’ by the asteroid that ultimately did them in, according to a new study
An international team of researchers from Italy, Norway, Canada and the US analyzed sulfur and fluorine gases trapped in layers of ancient volcanic rocks (labelled above right) from India’s Deccan Traps supervolcano. The volcanic gases likely led to temperature drops globally
‘Our research demonstrates that climatic conditions were almost certainly unstable,’ said study co-author and geologist Don Baker, ‘with repeated volcanic winters that could have lasted decades, prior to the extinction of the dinosaurs.’
‘Our work helps explain this significant extinction event that led to the rise of mammals and the evolution of our species,’ according to Baker, who teaches at Canada’s McGill University in Montreal.
The group analyzed trapped sulfur and fluorine compounds in samples taken from the Deccan Traps ‘lava pile’ in India’s Western Ghats mountain range, near Bombay.
The compounds’ minute concentrations, measured in parts-per-million, were determined via synchrotron radiation x‐ray fluorescence spectrometry — which bombards samples with magnetized corkscrews of radiation and then records how that radiation bounces and scatters back.
Some of the ‘volcanic winters,’ according to study co-author, geologist Don Baker, ‘could have lasted decades’ each, prior to the meteor that led to the dinosaurs’ extinction
Baker drew a cooking analogy to explain the process of calculating atmospheric sulfur and fluorine volume from the small percentages held within these lava rocks.
‘Imagine making pasta at home. You boil the water, add salt, and then the pasta,’ Baker began in a statement.
‘Some of the salt from the water goes into the pasta,’ he said, ‘but not much of it.’
Baker and his team worked with similar known ratios to estimate how much sulfur and fluorine gas compounds had flooded into Earth’s atmosphere during the Cretaceous period.
A steady drop in temperature during the late Cretaceous period, as estimated by past paleoclimate studies, happened to track with higher concentrations of the Sulfur compounds in several layers of ancient lava from the Deccan Traps: layers known as the Thakurvadi through Bushe rock formations.
Sulfur content was found to be as high as 1,800 parts-per-million in these layers.
By the researchers’ calculations, that would indicate that a volume of sulfur gas somewhere between 86,000 and 466,000 cubic-kilometers in size erupted into the prehistoric atmosphere.
When it came to the fluorine gasses, Baker and his colleagues do not believe it contributed to major climate change, but that its concentrations had other, more local, toxic effects.
‘There is historical evidence for local impacts of fluorine degassing,’ they wrote in their study, published in the journal Science Advances, ‘as readily deposited from the volcanic haze.’
Above, a November 2023 eruption from one of most active and tallest volcanos in Europe, the snow-capped Etna in Italy. Etna shows what global ‘volcanic winters’ might have looked like
Huge regions of western India were carved and grooved by the lava flows of the Deccan Traps supervolcano over 66 million years ago. Above, a SkySat satellite image of the Deccan Traps taken in March of 2018 over Maharashtrain in India
The ‘the final blow’ in the researchers’ view was almost assuredly the well-known Chicxulub impact, when a carbon-rich asteroid crashed into Mexico’s Yucatán Peninsula roughly 66 million years ago. The impact led to trillions of metric tons of dust clouds and a new Ice Age
Those local impacts included, ‘acid rain, crop failure, and livestock poisoning’ after Iceland’s Laki volcano eruptions in 1783 and 1784.
In essence, the researchers speculate that the Laki volcano’s fluorine episode might be a good example of how the Deccan Traps’ supervolcanic activity could have further harmed the dinosaurs over 66 million years ago.
‘Deccan Traps volcanism set the stage for a global biotic crisis,’ as the team put it in their new study, ‘repeatedly deteriorating environmental conditions by forcing recurring short volcanic winters.’
But the ‘the final blow’ in their view was almost assuredly the well-known Chicxulub impact, when a carbon-rich asteroid crashed into Mexico’s Yucatán Peninsula roughly 66 million years ago.
The impact, which left a six-mile-wide crater visible to this day, devastated the planet smashing up a hot cloud of dust, ash and steam and spreading 25 trillion metric tons of material into the atmosphere, some of which even escaped Earth’s orbit.
The heated rentry of the rest of that material caused forest fires across 70 percent of the planet and left massive dust clouds that hastened a new Ice Age, scientists say.
But the dinosaurs were already struggling with bad weather by that time, based on Baker and his teams’ new work.
‘Our dataset,’ they wrote, ‘indicates that volcanic-driven climate disturbance was already underway.’
HOW THE DINOSAURS BECAME EXTINCT AROUND 66MILLION YEARS AGO
Dinosaurs ruled the Earth around 66million years ago, but suddenly disappeared in what is known as the Cretaceous-Tertiary extinction.
It was believed for many years that the changing climate destroyed the food chain of the huge reptiles.
However, in the 1980s paleontologists discovered a layer of iridium – an element that is rare on Earth but found in vast quantities in space.
When this was dated, it coincided precisely with when the dinosaurs disappeared from the fossil record.
A decade later, scientists uncovered the massive Chicxulub Crater at the tip of Mexico’s Yucatán Peninsula, which dates to the period in question.
Scientific consensus now says that these two factors are linked and they were both probably caused by an enormous asteroid crashing to Earth.
With the projected size and impact velocity, the collision would have caused an enormous shock wave and is likely to have triggered seismic activity.
The fallout would have created plumes of ash thought to have covered the whole planet, making it impossible for dinosaurs to survive.
Other animals and plant species had a shorter time-span between generations which allowed them to survive.
There are several other theories as to what caused the demise of the dinos.
One early theory was that small mammals ate dinosaur eggs and another proposes that toxic angiosperms (flowering plants) killed them off.
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