Belgian boffins find colossal meteorite Belgian meteorite hunters scooting about Antarctica on skidoos have described what they say is the largest meteorite find on the frozen continent since 1988. Geologist Vinciane Debaille of the Université Libre de Bruxelles told the International Polar Foundation that she and her colleagues on an international meteorite-hunting …
Hit no. 2 on Google, introductory paragraph:
"Antarctica, it has been discovered, is the best meteorite trap on Earth. Firstly meteorites fall onto ice rather than hard rock and so are damaged less. Then, being rock, they stand out from their background unlike those falling in the temperate zones which will mainly be not distinguished from the local rock. Then there is a curious concentration process by which ice flowing outwards and meeting a rock or mountain obstruction, shears upwards bringing the enclosed meteorites to the surface. In many regions where ice is trapped against a mountainside and with no easy path to flow away, the ice is slowly reduced in thickness by solar ablation and ablation by katabatic winds, eventually after hundreds of thousands of years leaving a surface littered with extra-terrestrial objects."
http://www.rosssea.info/meteorites.html
Its better preserved because it doesn’t sit on acid/alkaline soil, it doesn’t get rained on, or fractured by blistering sunshine or collect several layers of mcdonalds and cheap alcohol containers.
The real reason though is you can find the buggers against a white background and they are preserved in the sense joe public tends not to get there first.
Alas after all this care and attention they will have high levels of Feinnes fingers.
If a bit of rock is found on the surface of the ice in Antarctica (or at any rate in an intelligently chosen subset of such locations), it is a meteorite, pretty much guaranteed. And rocks show on ice very well. And not many people about. And in places the ability to survey large areas with relative ease.
Taken together, they make it an ideal hunting ground. Compare temperate zones where there are rocks everywhere, lots of forest and private land, etc.
Think it may just be there's a better chase of spotting it sitting on the snow/ice. a lump of rock here couldn't come from many places, as the ice is many metres thick. Also having one drop on a rocky hill or grass covered earth means there's a lot of rock that isn't from space and would need to be sorted through
It's a combination of reasons, there is little precipitation in Antarctica so they don't get covered by snow and ice, likewise no vegetation to hide them. Most meteorites are black so they really stand out on the ice. (Similarly, the North African desert is a good meteorite hunting site because the meteorites sit on the surface for thousands of years).
If you're doing a magnetic survey, iron and stony-iron meteorites will be immediately visible to the sensors. Finally, those that do eventually get covered by the ice are transported to ablation zones where the ice sublimes and melts leaving meteorites behind, so you can get enormous concentrations of meteoritic rock at the toe of glaciers.
HTH.
Call me old fashioned, and excuse the technical scientific parlance, but surely a lump of rock big enough to end up as 18Kg on the surface would have been substantially toasty when it landed and punched what's commonly known as 'a big hole' in the snow?
In my mind, small though it is, I thought a hot stone may have melted itself a really good hole before it cooled anyway. Now (using possibly flawed logic and limited scientific knowledge) melted snow and ice may form, what we commoners call "water". And, if you have a rock cooling in a puddle does that not cause possible water contamination?
On the other hand, maybe the rock 'soft landed' so it didn't form a crater or any sort of hole ... but surely there'd be signs of its parachutes or retro-rockets?
strangely (well not really) small rocks tend to land at pretty close to ambient temperature. Fist sized rocks tend to land with the outside at around ambient and then cool rapidly as the innards are still very very cold from space.
Big rocks might land with the outside still hot and then get cold too.
If you watch the videos of the Russian jobbie you will see that the remains stop glowing a long long way up when its slowed down to a few mach and even the big one they found here will have a terminal velocity well below the speed of sound which gives it plenty of time to cool down.
Now a big iron meteorite will probably not break up but then the outside melts off like its being attacked by a mad welder. I'd give BIG money to watch one of those come in at night!
"but surely a lump of rock big enough to end up as 18Kg on the surface would have been substantially toasty when it landed and punched what's commonly known as 'a big hole' in the snow?"
Empirical results seem to dictate otherwise. I'd suggest writing a stern note to the rock in question!
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