Giant Impact Crater Found In Australia 109
An anonymous reader writes "One of the largest meteorite impacts in the world has been discovered in the South Australian outback by geothermal researchers. It may explain one of the many extinction events in the past 600 million years, and may contain rare and exotic minerals. The crater is said to have been 'produced by an asteroid six to 12 km across' — which is really big!"
Re:discovered? (Score:5, Informative)
Obviously not in the article.. not even one damn picture of it..
It is very difficult to photograph something that is 80-160 km across and buried under many layers of sediments... that may have something to do with the lack of pictures.
TFA doesn't mention when the discovery was made, so it is hard to say how much time they've had to produce some images for the media.
I can imagine that specialized satellites can scan the area for geological differences. But I imagine that Google Maps shows no sign of this crater at all.
Re:discovered? (Score:3, Informative)
Okay so they say in TFA that the crater has most likely eroded away, but they could have at least shown a map of the region with a yellow circle to indicate where they think it is.
Where? (Score:5, Informative)
TFA doesn't mention a location. There is a roughly circular sort of feature in about the right place and about the right size centred here:
http://maps.google.com.au/?ie=UTF8&ll=-28.614665,141.139984&spn=0.806518,1.234589&t=h&z=10 [google.com.au]
You can see it better if you zoom out a couple of steps. It's not very well defined, and may just be wishful thinking on my part!
Re:discovered? (Score:5, Informative)
> they could have at least shown a map of the region with a yellow circle to indicate where they think it is.
They said the geothermal researcher who discovered this crater was working in the Cooper Basin, South Australia.
http://en.wikipedia.org/wiki/Cooper_Basin
This is where it is:
http://www.hydrocarbons-technology.com/projects/CooperbasinAust/images/2-cooper-basin.jpg
The geothermal energy project in that area of the world is near the town of Innaminka.
http://en.wikipedia.org/wiki/Innamincka,_South_Australia
http://en.wikipedia.org/wiki/File:Innamincka_location_map_in_South_Australia.PNG
The geothermal energy project is there because the earth's crust at that location is unusually thin.
http://www.smh.com.au/news/environment/hot-rock-power-the-way-ahead/2007/04/11/1175971183212.html
http://www.adelaide.edu.au/adelaidean/issues/9461/news9469.html
The earth's thin crust in that area may actually have something to do with the impact crater.
This is a quite remote part of the world. Desert. There is almost nothing there.
It is not really surprising that this impact crater has not been discovered up until now.
Re:But how much energy is that? (Score:3, Informative)
Maybe it crashed into a limestone formation? Limestone (and other carbonate rock like marble and karst) are basically giant lumps of CO2.
Original Source (Score:3, Informative)
There's an article [uq.edu.au] on the University of Queensland's web site (where the researchers hail from).
The land surface that the asteroid hit is now buried under layers of sedimentary rock and Dr Uysal thinks the original crater most likely eroded away.
"Dr Uysal and Dr Glikson will present their findings at the Australian Geothermal Energy Conference in Adelaide, 16-19 November 2010."
To read more about their research, see their conference paper (pdf). [uq.edu.au] (This may not be specifically on the impact, but on their geothermal research, instead.)
In short, not the biggest, oldest, newest, or any other superlative. Still, given the estimated size of the impact, I'd expect it to have had a major impact on the Earth's weather for quite a while.
Especially limestone (Score:4, Informative)
Limestone is calcium carbonate, which releases tons of CO2 when burned.
Re:Meh, I've seen bigger... (Score:3, Informative)
As a quick guess I'd say the destruction would be limited to a relatively small area of the planet. You'd have total devastation within a radius of maybe a few hundred kilometers, but the rest of the planet would be fine. You wouldn't have ash encircling the planet and blocking out the sun as with a Chicxulub-type impact (which is by far the most devastating effect of a large asteroid impact to life on a planet), although you may still get some smaller Eyjafjallajokull-size ash clouds.
Now if it landed in the ocean you'd have serious mega-tsunamis that would wipe out of a lot of coastal areas all around the world, but again not devastating on a planetary scale.
Just my somewhat-educated guess.
Re:But how much energy is that? (Score:3, Informative)
Okay so they give widely varying estimates of the crater's size - assuming the centre value of 120 Km a +/- 60 Km ia one hell of a margin of error. I imagine that the energy released from such an impact is orders of magnitude greater than any nuke we could ever throw at each other. The article metions the release of CO2, but i thought that by definition asteroids were just lumps of rock. So where does the CO2 come from after the impact?
It is about 100,000 megatons, at its peak the world nuclear arsenal had around 20,000 megatons.
CO2 is released if the asteroid impacts a carbonate rock bed - it then releases the CO2 just like a giant cement kiln (which is a major source of human CO2 release BTW - about 5% of the global release).
Re:But how much energy is that? (Score:2, Informative)