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Why is the Sahara so special?

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#1 Ira

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Posted 09 April 2013 - 08:15 PM

The Sahara Desert is such a prolific producer of meteorites that it has its own designation - "NWA" - North West Africa. But why aren't all deserts prolific producers of meteorite specimens? They fall randomly and NWA is special because it is a sand desert where anomalous rocks are easy to spot by wandering nomads. Why isn't this true of other deserts? The Gobi desert, or much of Australia? They must be strewn with an equal number of meteorites. So, why aren't they found?

/Ira

#2 jbtaylor

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Posted 09 April 2013 - 09:03 PM

Ira,

Great question! While I am certainly no expert, I know that there are a number of factors at play as mentioned in the following article abstract about the Atacama:

http://onlinelibrary...1229.x/abstract

Also, the Sahara is by far the largest hot desert and there are local populations traversing it on a continous basis which increases the odds of meteorite discoveries. I remember reading an explanation about why the Gobi hasn't produced a lot of meteorites but I can't remember the reason or the source right off hand. Hot deserts in Oman have proven fertile hunting grounds and there have been quite a few discoveries in the Australian Nullarbor plain too.

#3 StarWars

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Posted 09 April 2013 - 10:02 PM



NOVA - Earth from Space..




The Sahara Desert is mainly made up of ancient krill. The Sahara Desert was at the bottom of the ocean many moons ago. The prevailing winds take krill dust across the ocean to Brazil and helps fertilize the Amazon jungle.


http://video.pbs.org/video/2334144059/


http://www.pbs.org/w...from-space.html

#4 peter scherff

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Posted 10 April 2013 - 05:59 AM

Hi Ira
I think political reasons keep the numbers of finds down in some areas. Australia passed laws about meteorite ownership and exporting in the wake of Bob Haag's discovery of Calcalong Creek. These laws greatly diminished the financial rewards available to meteorite hunters. The hunters then went else where. As for the Gobi, just try to get permission to hunt there. Many people think that with new BLM regulations, meteorite hunting in the American south west will be curtailed.

Thanks,

Peter

#5 Ira

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Posted 10 April 2013 - 08:56 AM

I thought NWA meteorites were discovered mostly by bedouin, not professional meteorite hunters. All of these deserts have native wanderers that traverse them. Although controlled exportation may reduce the value, it doesn't render controlled meteorites valueless. So, why so few from these other areas? You might not be able to buy them but they should be found and made available to science. Not to mention the, ummm...illegal trade that exists for all objects that are desired. For example, you can be shot for killing Rhinos but trade in Rhino horn still flourishes.

/Ira

#6 dreamregent

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Posted 10 April 2013 - 09:41 AM

Those political reasons referred to by Mr. Scherff above are certainly a big reason across most of the Middle East. If you look at a map of meteorite discoveries you'll find very little in the way of discoveries within those deserts. It's not confined to meteorites, though. There seems to be a general fear of allowing outsiders in to study much of anything these days...including geologists not connected to the oil industry & archaeologists. Additionally, there are safety concerns across much of this area as well.

#7 Glassthrower

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Posted 10 April 2013 - 01:08 PM

I discussed this once with a friend who lives in Mongolia.

The Gobi desert has a lot of native dark and black-colored rocks. Hunting for meteorites there would be a very tedious affair. Some areas of the Sahara and Omani deserts have similar native rock, and those area produce fewer meteorites because they are hunted less often. It's like a haystack full of fake needles.

And, as was said above, the Chinese are not going to let anyone come in to hunt and then leave with the specimens. The same goes for nations in the Sahara like Algeria. It's too dangerous to go there, and even if you did, you would not get official permission to leave with meteorites.

Best regards,

MikeG

#8 peter scherff

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Posted 10 April 2013 - 01:25 PM

Hi Ira,

I am not sure if you are aware of the "baggage" attached to the NWA meteorites. For example there are restrictions on meteorite exports from Algeria. How ever Algeria has a porous border with Morocco. Thus meteorites found in Algeria tend cross the border to be sold in Morocco. For this reason many educational institutions will not add NWA meteorites to their collections. So perhaps the meteorites from areas that you think are underrepresented are purposely mislabeled.

Thanks,

Peter

#9 Ira

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Posted 10 April 2013 - 08:32 PM

What about Australia?

/Ira

#10 jbtaylor

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Posted 10 April 2013 - 10:21 PM


Ira,

Australia has produced numerous finds, and was considered a meteorite hunters paradise before the restrictive laws were inacted. As Peter mentioned, the Australian ban effectively shut down the export/trade and ended the incentive to search for new meteorites in that country. But rest assured there are many undiscovered meteorites in the expansive outback of Australia.

And the aforementioned article indicated that the hot desert with the highest concentration of meteorites is in the Atacama not the Sahara.

Jon

#11 jbtaylor

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Posted 10 April 2013 - 10:30 PM

An abstract from 1991, well before the NWA rush we had the Australian rush:

http://connection.eb...anza-austral...

#12 Ira

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Posted 11 April 2013 - 05:15 AM

So these restrictive export laws not only prevent meteorites from leaving the country, they also discourage hunters who would otherwise find them, resulting in a net loss for all. :foreheadslap: Smart!

/Ira

#13 Glassthrower

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Posted 11 April 2013 - 04:07 PM

Yes, restrictive meteorite laws hurt hunters, collectors, dealers, and science. Everybody loses. :(






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