World's largest asteroid impacts found in central Australia

A 400 kilometer-wide impact zone from a huge meteorite that broke in two moments before it slammed into the Earth has been found in Central Australia

australia-meteorFrom Australian National University:

A 400 kilometre-wide impact zone from a huge meteorite that broke in two moments before it slammed into the Earth has been found in Central Australia.

The crater from the impact millions of years ago has long disappeared. But a team of geophysicists has found the twin scars of the impacts – the largest impact zone ever found on Earth – hidden deep in the earth’s crust.

Lead researcher Dr Andrew Glikson from The Australian National University (ANU) said the impact zone was discovered during drilling as part of geothermal research, in an area near the borders of South Australia, Queensland and the Northern Territory.

“The two asteroids must each have been over 10 kilometres across – it would have been curtains for many life species on the planet at the time,” said Dr Glikson, from the ANU School of Archaeology and Anthropology.

The revelation of such ancient violent impacts may lead to new theories about the Earth’s history.

“Large impacts like these may have had a far more significant role in the Earth’s evolution than previously thought,” Dr Glikson said.

The exact date of the impacts remains unclear. The surrounding rocks are 300 to 600 million years old, but evidence of the type left by other meteorite strikes is lacking.

For example, a large meteorite strike 66 million years ago sent up a plume of ash which is found as a layer of sediment in rocks around the world. The plume is thought to have led to the extinction of a large proportion of the life on the planet, including many dinosaur species.

However, a similar layer has not been found in sediments around 300 million years old, Dr Glikson said.

“It’s a mystery – we can’t find an extinction event that matches these collisions. I have a suspicion the impact could be older than 300 million years,” he said.

A geothermal research project chanced on clues to the impacts while drilling more than two kilometres into the earth’s crust.

The drill core contained traces of rocks that had been turned to glass by the extreme temperature and pressure caused by a major impact.

Magnetic modelling of the deep crust in the area traced out bulges hidden deep in the Earth, rich in iron and magnesium, corresponding to the composition of the Earth mantle.

“There are two huge deep domes in the crust, formed by the Earth’s crust rebounding after the huge impacts, and bringing up rock from the mantle below,” Dr Glikson said.

The two impact zones total more than 400 kilometres across, in the Warburton Basin in Central Australia. They extend through the Earth’s crust, which is about 30 kilometres thick in this area.

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151 thoughts on “World's largest asteroid impacts found in central Australia

    • That was my thought as well. Australia is still a modern beneficiary of the late heavy bombardment, given the vast amount of minerals/iron etc deposited there.

      • The iron was from stromatalites, which are still to be found in coastal Western Australia. Perhaps meteorites gave us our argyle diamonds as well. One thing we did NOT receive from cosmic forces was decent politicians and unbiased media.

      • Donb, Argyle diamonds are volcanic origin. Plus they are some billions of years old – not millions.

      • Well there was an impact zone of a different kind last night at the Sydney Cricket Grounds, when Australia dispatched defending World Cricket Cup Champions, India, with a diabolical fielding strategy to defend their 329 run batting total in the first half of the game.
        The Indians could score a run if they just tapped the ball out of the pitch, as there were no Aussie fielders in sight. But they couldn’t get any more than a single, and the ball count was going down faster than the run count was going up, so India ended up needing at least three runs per ball for about the last ten overs to win. It was gruesome to watch. But finally the Indian batters just all dived off a cliff together, to get it over with so they were all out with about 20 more balls left on the table.
        But no lives were lost in this event, and the Aussie / Kiwi first ever Tasman Sea World Cup final will be a humdinger.
        G
        now back to your regularly scheduled programming.

    • I would be cautious about interpreting this structure as truly an impact. Without corroborating evidence beyond those mentioned, the argument for an impact is weak. Glass can be produced in many ways, and hot plumes rising from the mantle are by no means rare.

      • Yeah; I read an article in one of the Australian newspapers about the find, and they said it was a bit premature to claim it as an impact crater, and evidently, not a lot of dating evidence so they aren’t too sure of its age.
        But I would expect that impacts of that size, would cause a lot of disruption whenever they happened.
        G

    • Is this time frame adequate for tectonic movement and mixing to destroy all evidence such as is found in the meteorite strike 66 million years ago?

  1. The Sudbury Basin in Canada: “60 km long, 30 km wide and 15 km deep. It was created as the result of a 10 km cometary impact that occurred 1.85 billion years ago in the Paleoproterozoic era. Its present size is believed to be a smaller portion of a 250 km round crater that the bolide originally created. Subsequent geological processes have deformed the crater into the current smaller oval shape. Sudbury Basin would then be the second largest crater on earth, after the 300 km Vredefort crater in South Africa, and larger than the 170 km Chicxulub crater in Yucatán, Mexico which is linked to the extinction of the dinosaurs.”
    http://www.canadaka.net/achievements/52-sudbury-basin-largest-meteor-crater-in-canada.html
    I think it also possible that the circular geometry of the west coast of Quebec on Hudson’s bay and possibly even the Bay itself could have been shaped by huge impacts in the very distant past.
    https://ca.search.yahoo.com/search?fr=mcafee&type=B111CA662D20141029&p=map+of+Quebec+province
    There are several smaller round craters in Quebec. Take a look at these babies!
    https://ca.images.search.yahoo.com/search/images;_ylt=AwrBTv6AXBBVpaEAxHLrFAx.;_ylu=X3oDMTBsa3ZzMnBvBHNlYwNzYwRjb2xvA2JmMQR2dGlkAw–?_adv_prop=image&fr=mcafee&va=Quebec+circular+crater+lakes

  2. At 460 million years ago, the Ordovician, the approximate mid-point of the impact time-range, what became Australia was close to the equator; the preferred impact zone for a bolide originating from the ecliptic. Likewise during the Proterozoic, 650 million years ago.

    • I guess this asteroid and a gamma ray burst caused the ice age during the Ordovician-Silurian extinction. It could cause an impact winter but photochemical smog from gamma rays is needed for the cold period to last 500,000 years.

  3. Bill….were they 10 kms across on impact? Or originally before they entered our atmosphere? Can that be determined by “the two impact zones total more than 400 kms across”?

    • Doesn’t matter. The amount of material burned up in the atmosphere would be very small. It only takes seconds to reach the surface. Then one can think of it as when it first touches the ground, the top of the asteroid is still 10 kms high in the atmosphere, the lower troposphere, and higher than most clouds.

      • Bill Illis
        I think the word significant is not inappropriate in that context, given that Mt Everest is <10 Km tall.
        +several
        Auto

  4. I’m going employ idiotic alarmist style causation. Large Asteroids struck earth before people started burning fossil fuels, a large asteroid hasn’t struck earth since humans started burning fossil fuels. Burning fossil fuels keeps large asteroids from striking the earth.

      • Yes Lisa. Same logic says CO2 drives global warming. You do see now that your chain got yanked right?

      • I have a fence around my house, but by inverting my reasoning; I have enclosed ALL tigers in the world by my fence. (I hope!)

      • Lisa
        Ok…now we got a falsifiable prediction…
        Your theory’s only 6 hours old and it’s already better than 25+ years of (IPCC) global warming almost-kinda-sorta theory. It’s also well known that 97% of people do not want to be eaten by a tiger.

      • I tear up copies of the local rag ‘The Sun’ whilst on the train to London.
        Ever day. It works.
        But …
        Yesterday, someone asked me why . . . .
        I explained that it kept the mastodons away.
        The guy said ‘There are no mastodons here!’
        I nodded, and added ‘Well it IS effective, isn’t it . . . .’
        Ahhhhhhhhh . . . . !
        The old ones are the good ones – are they not?
        Auto

      • old44:

        No tigers in Australia, you may be on to something.

        Nope! The crocodiles, white pointers, funnel webs, blue-ring octopus, stone fish, taipan and box jelly-fish drove them out.

      • I once saw a man eaten by a Tiger. He didn’t seem to be enjoying it. He must have been part of the 97%.

  5. 10kms across assumes a lot about their composition and other knock on variables such as did they air burst? We do live in a violent universe.
    Pointman

    • Really big bolides don’t airburst. There isn’t time to heat them up. And the composition matters less than one might think with really large objects.

  6. Or-strain ? and repercussions from the impact are still affecting the mentality of the Or-strain flat earth society

  7. Wow!
    There is sooo much we do not know about how this wonderful planet responds to true catastrophes such as this double pounding by 10km meteorites. It makes the piddling wiggle watching of +/- 1C change in ‘global temperature’ and all of the hyperbolic rhetoric (with 97% certainty!) of impending ‘catastrophe’ fade into complete insignificance, by comparison.
    Perspective parries pernicious propaganda.

      • Didn’t work for me I can alliterate with the best of them but my hair still fell out. Or is it that I have a very high forehead (up across the top and on its way down the back)
        James Bull

      • Active brains generate greater heat… and must radiate it through the scalp, leading to ‘hemispherical heating’ and increasing follicular failure. That’s my hypothesis…. and I’m sticking to it. If alliteration alleviated alopecia, it would ‘hirsute’ me well! But alas, my thinning scalp would not be fit to adorn the most timid coup pole.

      • ….but avoid the smart ass who takes your hat off, calls you a poor magician, and says “see, there is no hare in their”

      • Mac I had someone tell me years ago that as you get older the hair roots go deeper, if they find grey matter they turn grey if they find nothing they fall out.
        David loved the hat gag
        I just tell people it’s a solar panel for a sex machine.
        James Bull

    • Just rode my harley from the bottom to the top of oz, up through the middle, it is the oldest land mass on earth, God only knows what happened to it in the past. It is looking very old only a few Mesa,s left the rest washed away. My understanding was that Oz was part of antarctica and has been drifting North. I am in darwin. Hot as hell, the landscape is so old that all ancient catastrophise would be well washed away. Good luck to the researchers trying to make some sense of it all.

  8. With that scale of impact, they need to check for layered magmas with precious metals. At any rate it takes time for evidence to build up. This will take a methodical science approach as opposed to overreach climate witch hunting.

    • Are you thinking of Sudbury? Or a thin fallout layer with elevated platinum-group content? That is not easy to find for impacts older than the Jurassic where there are no undisturbed deep-ocean sediments.

  9. I recall reading somewhere that a really large meteor strike would cause a pressure spike in the molton core and massively increased magma eruptions. Is that still the theory?

    • It is known from other planets (Mercury, Mars) that the effects of really large impacts are focussed at the antipodal point and can cause large-scale magmatic activity there, but there is no undisputed case where this has been proven on Earth.

      • The End Cretaceous impact in Yucatan was anitipodal to the Deccan Traps, but they seem to have been erupting already when the bolide hit.

      • large-scale magmatic activity
        ==============
        hit a bar of iron with a hammer and you can turn the iron bar into a permanent magnet.

      • The Deccan Traps were not antipodal to Chicxulub impact site/crater.
        Remember there has been continental drift since 65 million years ago and the impact site would have been about where Puerto Rico is today. This would make it antipodal to an area south of Indonesia today which is not geographical where the Deccan Traps occured in the Indian Ocean directly south of India today. There is still a less-active magma plume/hotspot there today south of the Maldives.

        • Remember there has been continental drift since 65 million years ago and the impact site would have been about where Puerto Rico is today.
          Look again: How far do you believe the Indian continent has moved towards the Himalaya’s in only 65 Million years?
          PS. The Gulf of Mexico impact was 63-65 Myear ago, what were the dates of the Deccan lava flows?

      • “The Gulf of Mexico impact was 63-65 Myear ago, what were the dates of the Deccan lava flows?”
        According to Wikipedia, the dates are 66Ma in both cases.\
        http://en.wikipedia.org/wiki/Deccan_Traps
        http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event
        A curious coincidence at the very least. Just looking at a globe shows that the Yucatan impact is pretty darn close to 180 degrees different from the Deccan Traps by longitude. However, both the impact and the Traps are now at about 20 degrees North. 20 degrees south is in the middle of the Indian Ocean.
        It would be interesting to know more precisely the relative drift of those two locations over the past 66 million years.

      • Here is a short video that animates the continents over the past 250Ma. It shows an illustration at 66Ma that has India well below the equator, and pretty close to antipodal to what is now eastern Mexico.
        Pretty cool theory, at least.

        [Thank you for the research and the effort of replying. .mod]

      • Bill, True. I should have said roughly.
        IMO the Deccan Traps were caused by the Indian Plate passing over the Reunion Island hotspot.
        Some think hotspots are created by impacts penetrating the crust.

        • Sturgis Hooper

          IMO the Deccan Traps were caused by the Indian Plate passing over the Reunion Island hotspot.
          Some think hotspots are created by impacts penetrating the crust.

          The concept (of opposite-side effects to a collision on one side) is that the impact itself doesn’t penetrate (and of course the crater is not that deep), but that the shock waves enter the mantle and re-focus around the not-quite-a-liquid but very dense core to cause a massive shock zone on the opposite side of the sphere. Since the core itself is spherical and the shock waves travel so much faster than the rotation of the earth, the impact is expected to “mirror” across the equator and the longitude line.

  10. The word from other geologists who have worked on the Warburton basin is that it is from Early Cambrian to Middle Ordovician in age. This would mean that if it is associated with a mass extinction, the End Cambrian, Dresbachian or End-Botomian ones would seem most likely. The End-Botomian was possibly the second greatest marine extinction event after the End-Permian one.

  11. This is why it’s so important to colonize space. But we’re going to have to create a human with four arms and a tolerance for zero g, radiation and confinement. Once Man learns to live in space here, he could easily do it at Alpha Centuri. Then some form of humanity will be immortal.

    • No – diamonds come from very deep in the Earth. The diamonds found in impact deposits are microscopic. There is a theory though that all diamonds were originally formed by the really big impacts that occurred back in the Hadean more than 4 billion years ago, but those were orders of magnitude larger than anything that has happened since then.

      • Red/pink diamonds come from other, already formed diamonds, that are later exposed to some sort of deforming force.

    • Scot, the Argyle diamond mine is nowhere near this impact crater. It is in extreme NW Australia. And is a classic kimberlite ‘pipe’ system of volcanic origin. Now, did the impact cause the vulcanism? Not if the geological assessments of Argyle’s origins are correct. Google can be your friend. Amazing what can be learned in just a few minutes.

  12. I think this is the first time I have read anything by Andrew Glikson that doesn’t tell me that CO2 is a menace and we are all doomed.

  13. So how do you know there was no mass extinction associated with it if the date range is so wide at this early stage?

  14. Does Glikson have any credibility? He was one of the “Climate Commission” which included the spectacularly mendacious alarmists Tim Flannery, Will Steffan, and David Karoly.

    • IPCC TAR 2001 WG1 1.2.1 and Appendix 9.1. ‘Official’. Derived from spectral radiative transfer codes like Modtran. For some less certain detail on how this canonical value translates into zero feedback warming at different lattitudes, see Judith Curry’s Climate Etc. 12/11/2010.

  15. The Earth in the mid Phanerozoic was largely ocean with less land area than now. I suspect that this means the earth system was more robust against bolide impacts, maritime influence would stabilise climate quite strongly and rapidly after an impact.

  16. So a question. Why was anybody doing this geothermal energy research in the almost exact middle of the outback in the first place? Nutty waste of Australian taxpayer dollars.
    Geothermal only makes sense in tectonic rift (Iceland) or subduction (US West Coast) zones where you can get close to mantle temperatures. Yellowstone hot spot would be a lovely exception, but might upset Greenies to plumb Old Faithful for their renewable energy.
    South Africa’s deepest goldmines are now near 3km, one km deeper than these Australian drill cores. Temp at the working face is a ‘blistering ‘ 165F. Hot water, yes. Geothermal energy, not by a long shot. Just basic Rankin cycle math. Darned those old laws of thermodynamics, discovered at the same time as coal was first used to power steam engines.

  17. If there was any sort of computer modeling witchcraft involved then we might as well flush the whole story down the pan.

    • Just be careful about distance though or you get “Your position is inside the fireball”. Oh goody. 😉

  18. If you assume that asteroid impacts are essentially random in distribution, and given that 70% of the earth is covered by water, it would be reasonable to assume that for every old impact you find on continental crust there were probably 2.3 that occurred in the oceans some where.

    • Larry Ledwick
      March 23, 2015 at 3:41 pm

      If you assume that asteroid impacts are essentially random in distribution, and given that 70% of the earth is covered by water, it would be reasonable to assume that for every old impact you find on continental crust there were probably 2.3 that occurred in the oceans some where.

      Much of today’s exposed-to-the-atmosphere continental rock is fairly recent: Only a few areas around Australia, Africa and the central Canadian tundra are “original rock” in that they’ve been exposed to bombardment for 3.7 billion years or more. The rest of today’s continents are ex-seafloor moved around, bumped up and submerged and piled into mountains chains, etc. The seafloor is also fairly new: The oldest rocks under the heavy cover of debris and whale poop are getting jammed under the continental rocks in the trenches at the edge of the continents.
      http://en.wikipedia.org/wiki/Crust_%28geology%29
      Other areas around ocean floor expanding points (the Atlantic’s east and west coastlines) for example, may have comet impact craters – but they’ve been buried under 1 kilometers of more whale and shark poop.

      • “but they’ve been buried under 1 kilometers of more whale and shark poop.”
        Perhaps the MIA heat is in a giant compost pile at the bottom of the sea. I knew it was some form of manure. (-;

    • Because earlier oil and gas drilling showed that the region was geothermally hot, and that’s where most of the onshore drill rigs are concentrated.
      Ciao
      John

  19. Why would such a large object break in two ‘moments’ before impact? Surely the thermal shock would be superficial over such a brief encounter with the atmosphere.
    (The Thunderbolts folks would probably say that there was a large voltage differential between the earth and the object, and upon nearing the earth, quickly increasing internal electrical stresses causes the break-up, similar to an exploding over-charged capacitor.)

    • Max Photon

      Why would such a large object break in two ‘moments’ before impact? Surely the thermal shock would be superficial over such a brief encounter with the atmosphere.

      But look at the 20+ objects that comet shoemaker-levy busted up into during just one loop around Jupiter prior to its fatal impact – and that impact was spread out over some 15 days, only 1-1/2 years after the original comet was slung around the planet. These things are not necessarily all that well glued together into single round solid objects.
      Which is why I question severely (laugh at) any thoughts and plans of actually getting a remote-controlled, 15 minutes lag time-between-phone-calls-radio-signals to control a “lander on a spinning irregular-shaped irregularly cemented-together “comet” and attach a “lanyard” exactly on the “south pole” to “pull it” away from the future earth’s orbit intercept point. A pipe dream.

    • “Why would such a large object break in two ‘moments’ before impact?”
      It would have happened slightly earlier when it crossed the Roche limit. At ordinary orbital speeds that would be 5-10 minutes before impact. Many asteroids ar “rubble piles” only held together by gravity.

  20. This must be due to climate change. Let’s see if the climate modelers can hindcast and predict the time and place of impact!

  21. To take a sobering count of just how “likely” a continent-sized (or planet-sized!) blast cloud can be, consider that in less than 20 years, 25 huge impacts have been photographed on Jupiter alone. (21 from comet Shuemaker-Levy-9, and 4 additional impacts)
    None were expected. Only the comet was seen before impact – and that only because as a comet, it did become bright enough to see by telescope. Yes, Jupiter has a huge gravitation field, and yes, it is closer to the asteroid belt. But ….
    See this Wkipedia page for links to each of the other impacts.
    http://en.wikipedia.org/wiki/List_of_Jupiter_events
    Impacts
    September 2012 Jupiter impact event[2]
    August 2010 Jupiter impact event[2]
    June 2010 Jupiter impact event
    2009 Jupiter impact event
    Comet Shoemaker–Levy 9 (1994 impact event)

  22. Not only some of the largest, but some of the oldest and some of those can be barely seen from the ground because they have, literally, been worn away by erosion over time.

  23. For those who ponder if the Deccan Traps flood basalts were due to to the Chicxulub impact, please see the link.
    /www.sci-news.com/geology/science-deccan-traps-volcanism-dinosaur-extinction-02345.html
    or if you have an account (paywall)
    Blair Schoene et al. U-Pb geochronology of the Deccan Traps and relation to the end-Cretaceous mass extinction. Science, published online December 11, 2014; doi: 10.1126/science.aaa0118
    Briefly, more exact rock dating has placed a beginning date for the eruptions at 250,000 years prior to the impact and extending 500,000 years after. I would say that there is strong evidence that they are neither linked either by time or process.

  24. If rocks ~300MY were affected, the impact would have been younger. If the surface layers at the time of impact have been removed by later erosion, the age of the unconformity between affected rock and over burden without signs of impact will give the oldest possible date for the impact. In view of the global effects expected, I’d look at the Permo-Triassic boundary at 252 mya as a possible impact date.

  25. The earlier comment about bolides was mistaken: the fracture of a meteor in the atmosphere has little to do with heating (although there is plenty of heat). The meteor is supersonic and thus creates a shockwave ahead of itself. There is a high overpressure behind the shockwave, in front of the meteor, where the incoming airflow “stagnates” or comes nearly to rest relative to the meteor. This constitutes an axial compression load against the meteor (overpressure vs. inertia). Once the compression strength of the meteor is exceeded, it fractures (releasing compression strain energy in the process). If it is a small meteor (bolide), this manifests as an apparent “explosion,” even though nothing actually explodes (like TNT).
    This fracture mechanism could have happened to the Australian monster collider, but it requires a determination of how fast the speed of sound was within the material body of the meteor, since pressure effects are communicated basically at the speed of sound within a material. It is not clear how they come to this conclusion of a fractured body at impact, since the fragments would not have had significant time to separate.
    There is a further twist to this scenario. As the impact proceeds, the first thing to occur will be the high-speed contact of the shockwave with the surface of the Earth. This will cause a reflection of the shockwave, and the pressure ratio across the shockwave will be the square of what it was coming in. This will create a very high-pressure seismic spike into the Earth. The reflected wave will travel back and reflect again off the meteor, where the pressure ratio across the shockwave squares yet again. It is at least plausible that if the meteor had not fractured in response to the original shockwave, it might well fracture in response to this sudden fourth-power increase of the shockwave pressure ratio, just before impact.

  26. The impact of one of these strikes on a major ocean basin would be almost as devastating as political climate change over reach. Either way the unsuspecting populations in the way of these policy-caused and natural events are helpless.

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