Imperial College London
The simulations show that the asteroid hit Earth at an angle of about 60 degrees, which maximised the amount of climate-changing gases thrust into the upper atmosphere.
Such a strike likely unleashed billions of tonnes of sulphur, blocking the sun and triggering the nuclear winter that killed the dinosaurs and 75 per cent of life on Earth 66 million years ago.
Drawn from a combination of 3D numerical impact simulations and geophysical data from the site of the impact, the new models are the first ever fully 3D simulations to reproduce the whole event – from the initial impact to the moment the final crater, now known as Chicxulub, was formed.
The simulations [2] were performed on the Science and Technology Facilities Council (STFC) DiRAC High Performance Computing Facility.
Lead researcher Professor Gareth Collins, of Imperial’s Department of Earth Science and Engineering, said: “For the dinosaurs, the worst-case scenario is exactly what happened. The asteroid strike unleashed an incredible amount of climate-changing gases into the atmosphere, triggering a chain of events that led to the extinction of the dinosaurs. This was likely worsened by the fact that it struck at one of the deadliest possible angles.
“Our simulations provide compelling evidence that the asteroid struck at a steep angle, perhaps 60 degrees above the horizon, and approached its target from the north-east. We know that this was among the worst-case scenarios for the lethality on impact, because it put more hazardous debris into the upper atmosphere and scattered it everywhere – the very thing that led to a nuclear winter.”
The results are published today in Nature Communications.
Crater creation
The upper layers of earth around the Chicxulub crater in present-day Mexico contain high amounts of water as well as porous carbonate and evaporite rocks. When heated and disturbed by the impact, these rocks would have decomposed, flinging vast amounts of carbon dioxide, sulphur and water vapour into the atmosphere.
The sulphur would have been particularly hazardous as it rapidly forms aerosols – tiny particles that would have blocked the sun’s rays, halting photosynthesis in plants and rapidly cooling the climate. This eventually contributed to the mass extinction event that killed 75 per cent of life on Earth.
The team of researchers from Imperial, the University of Freiburg, and The University of Texas at Austin, examined the shape and subsurface structure of the crater using geophysical data to feed into the simulations that helped diagnose the impact angle and direction. Their analysis was also informed by recent results from drilling into the 200 km-wide crater, which brought up rocks containing evidence of the extreme forces generated by the impact.
Peak performance
Pivotal to diagnosing the angle and direction of impact was the relationship between the centre of the crater, the centre of the peak ring – a ring of mountains made of heavily fractured rock inside the crater rim – and the centre of dense uplifted mantle rocks, some 30 km beneath the crater.
At Chicxulub, these centres are aligned in a southwest-northeast direction, with the crater centre in between the peak-ring and mantle-uplift centres. The team’s 3D Chicxulub crater simulations at an angle of 60 degrees reproduced these observations almost exactly.
The simulations reconstructed the crater formation in unprecedented detail and give us more clues as to how the largest craters on Earth are formed. Previous fully 3D simulations of the Chicxulub impact have covered only the early stages of impact, which include the production of a deep bowl-shaped hole in the crust known as the transient crater and the expulsion of rocks, water and sediment into the atmosphere.
These simulations are the first to continue beyond this intermediate point in the formation of the crater and reproduce the final stage of the crater’s formation, in which the transient crater collapses to form the final structure (see video). This allowed the researchers to make the first comparison between 3D Chicxulub crater simulations and the present-day structure of the crater revealed by geophysical data.
Co-author Dr Auriol Rae of the University of Freiburg said: “Despite being buried beneath nearly a kilometre of sedimentary rocks, it is remarkable that geophysical data reveals so much about the crater structure – enough to describe the direction and angle of the impact.”
The researchers say that while the study has given us important insights into the dinosaur-dooming impact, it also helps us understand how large craters on other planets form.
Co-author Dr Thomas Davison, also of Imperial’s Department of Earth Science and Engineering, said: “Large craters like Chicxulub are formed in a matter of minutes, and involve a spectacular rebound of rock beneath the crater. Our findings could help advance our understanding of how this rebound can be used to diagnose details of the impacting asteroid.”
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1. IIRC, experimental data regarding impact inclinations showed that only the most extreme angles can form non-circular craters.
2 The variables regarding size, composition, etc. are all up for debate. Does inclination have any special property that cannot be reproduced in a half dozen other ways?
3. So not only were there enormous tsunamis, but also a massive shockwave and incredible heat produced by this impact. Dr. Bakker is no fool in this regard, and his observation about frogs is particularly stinging. When you consider all the species that survived, one major trait is shared: they all depended heavily upon shelters.
For some the shelter was simply aquatic. Many marine species perished, but mainly because of lost food sources or oceanic chemistry changes. Also distance from the impact site. Antarctic surival has been noted, but also North Polar crocodilian relatives survived.
And of course, we mammals, then mainly small, burrowing, nocturnal creatures.
No world wide flood but I wouldn’t have wanted to have been holidaying in my beach shack.
As for…” billions and billions of dinosaurs and other animals and plants laid down suddenly and violently all over the world IN WATER?”
If they hadn’t been laid down in water and subsequently covered in silt and mud we wouldn’t know about them. If their carcasses were left scattered about on land surviving scavengers would have dispersed their remains.
Volcanic eruptions can also bury carcasses, leaving behind excellent detail. But even just normal windborne deposits can create fossils should by chance no predator find the remains and spread them around.
But deposition in shallow, anoxic water is the best way to make fossils, especially the most detailed, in Lagerstätten.
So any reason this simulation/model is likely to be any more useful than the infamous COVID/WuFlu model? Just asking.
Yes. For good reasons.
Bruce,
Still worried about mechanisms able to produce SO2.
Is there supporting evidence that 900C is possible and wisespread from impacts?
Is your equation derived with air present or absent?
How would 900C affect shock patterns in crystals? Annealing?
Many possible sulphur to SO2 or SO3 require oxidants like a lot of oxygen.
Sulphide ore blast furnaces rely on oxgen. Inorganis sulphides are formed by a lot of reduction chemistry energy, hard to reverse to SO2.
Is the mix after an impact strongly oxidising or reducing?
Is there enough time after impact to allow mixing and heat to produce much SO2?
It is not axiomatic.
Note: I am not claiming that impacts make no SO2 and SO3.
I am postulating that these are hard to make and that researchers should not assume willy nilly that they would be created abundant enough to do all of the many amazing things claimed by global warming scaremongering. Geoff S
Geoff – The impactor fell onto an area with a large substratum of gypsum. Freeport has extracted elemental sulfur in that area for many years due to bioreduction of the same stratum. And I’ve actually calcined similar compounds in a TGA – they do dissociate into oxide plus SO2 above about 900 C. I’ve even a patent or two on such things.
Above 900C the sulfates are in thermodynamic equilibrium with SO2, O2 and the oxides. SO2, SO3 and O2 also tend to be in an equilibrium above a certain temperature. I’d have to look it up.
Temperatures well in excess of 900C are very likely under a kilometre sized lump of rock falling at 20km/s.
Once I donned a suit and stuck my head into a SO3 absorption tower. We were trying to find out why we were getting mercury contamination of our sulfuric acid. It was fun.
Thanks for your expertise and experience. Here’s an incomplete link to 1994 expeerimental research on sulphate production at the impact site:
http://adsabs.harvard.edu/full/1994LPI….25..413G
High-Temperature Vaporization of Gypsum and Anhydrites: Experimental Results
Broken link doesn’t work, but searching for the paper title will get you there.
Bruce,
And my young family and I lived for a year about 500 m from the unscrubbed smelter chimney at Mt Morgan, so high SO2 was a fact of life.
People often find it hard to envisage geologic dimensions and time scales. I have spoken with many people who have no idea of stuructures below their feet. Many believe in sunlit underground streams where living creatures frolic like in fairy tales. Concepts like soil horizons and stratification are unknown to them. Sometimes such people write about earthly phenomena that are nothing to do with reality.
There is no doubt that bodies from the sky can hit the Earth at high velocity. There are estimates of the energy transfer, but then matters can become more speculative. Like, people invoke large quantities of SO3 with little experience of whether it can form under the conditions of impact and the time allowed. It requires strong oxidation. Where does the oxidant come from, how long is it there, can it mix, can much SO3 escape to air before becoming sulphate? My point is that mathematical calculations with chemical processes are needed, not just an assumption that evaporites were present so SO3 must form. Geoff S
Experimental study of SO2/SO3 ratio in impact vapor plumes using a high-speed laser gun: initial results
https://meetingorganizer.copernicus.org/EPSC2010/EPSC2010-184-1.pdf
New Geochemical Insights from Electron-Spin- Resonance Studies of Mn2+ and SO3- in Calcites: Quantitative Analyses of Chicxulub Crater Ejecta from Belize and Southern México with Comparison to Limestones from Distal Cretaceous-Tertiary-Boundary Sites
https://www.researchgate.net/publication/305116778_New_Geochemical_Insights_from_Electron-Spin-_Resonance_Studies_of_Mn2_and_SO3-_in_Calcites_Quantitative_Analyses_of_Chicxulub_Crater_Ejecta_from_Belize_and_Southern_Mexico_with_Comparison_to_Limestone
“Temperatures well in excess of 900C are very likely under a kilometre sized lump of rock falling at 20km/s.”
Much, much more. The stagnation temperature on a re-entering satellite (8 km/s) is typically 3,000-4,000 C. A meteorite is literally hotter than the sun. Those dinosaur in the illustration at the top would be dead within a second or two after the the bolide entered the atmosphere.
Look at the videos of the Chelyabinsk bolide on Youtube, then multiply by several billions…
Yup. A bad day in Black Rock, Baja and locations much farther afield.
Of known craters, the third biggest. The two larger hit within less than 200 million years of each other in the Paleoproterozoic, ie Vredefort, South Africa, ~2.02 Ma, and Sudbury, Canada, ~1.85 Ma.
Hot, hot, hot in the Yucatan that doomsday.
Such a strike likely unleashed billions of tonnes of sulphur, blocking the sun and triggering the nuclear winter that killed the dinosaurs and 75 per cent of life on Earth 66 million years ago.
That is gibberish. The strike unleashed a stratospheric blocking ‘winter’. The so called ‘nuclear winter’ is just an effect of models. It is not a real thing.
The soot-based “nuclear winter” scare was bogus, but sulfur aerosols do block sunlight.
DOUBLE-PLUS GOOD DOCUMENTARY,
See it twice!
The Last Day of the Dinosaurs
Bruce,
And my young family and I lived for a year about 500 m from the unscrubbed smelter chimney at Mt Morgan, so high SO2 was a fact of life.
People often find it hard to envisage geologic dimensions and time scales. I have spoken with many people who have no idea of stuructures below their feet. Many believe in sunlit underground streams where living creatures frolic like in fairy tales. Concepts like soil horizons and stratification are unknown to them. Sometimes such people write about earthly phenomena that are nothing to do with reality.
There is no doubt that bodies from the sky can hit the Earth at high velocity. There are estimates of the energy transfer, but then matters can become more speculative. Like, people invoke large quantities of SO3 with little experience of whether it can form under the conditions of impact and the time allowed. It requires strong oxidation. Where does the oxidant come from, how long is it there, can it mix, can much SO3 escape to air before becoming sulphate? My point is that mathematical calculations with chemical processes are needed, not just an assumption that evaporites were present so SO3 must form. Geoff S
Mixing large quantities of superheated sulfur into an atmosphere with 20+ % oxygen can hardly result in anything but large quantities of SO2 and SO3. Undoubtedly there were immense quantities of NOx as well, and large amounts of chlorine compounds as well from evaporated seawater.
Tektite glass forms only in the heat of asteroid impacts and high-yield nuclear detonations. Inside T of a nuclear fireball reaches 100,000,000 degrees C. The Yucatan impact released on the order of 100,000,000 times more energy than 50-MT Tsar Bomba, the largest thermonuclear detonation. Granted, the physics of impacts differ from atomic explosions, and between ground air air bursts, but that bad day surely yielded local temperatures at least in the thousands of degrees C.
Should read “ground and air bursts”.
Really, the Imperial College? Aren’t these the same fools who predicted we would have devastating deaths due to the Coronavirus? So we’re suppose to believe this bullshit that they have put out there? Who created the code for their models?