Gibeon Meteorite Fountain in Windhoek, Namibia
The Gibeon Fountain is a display of meteorites from the Gibeon meteorite shower.
The exact date when these meteorites came down near the small settlement of Gibeon in Namibia is unknown, but since prehistoric times the local Nama people picked up meteorites that lay on the ground's surface and made arrowheads and assagai-heads, a javelin type weapon made of long, thin pointed iron rods with sharp edges.
In 1838 we have record of the explorer James Alexander , who collected small pieces of metal on his journey around the Gibeon area.
The meteorite pieces can be found still today in an area of 275 km by 100 km south of Mariental, but it is forbidden by Namibian law to remove them from their original site.
Despite that fact, quite a number of them are still smuggled out of the country and might be found at international rock and mineral shows.
"Consisting of two different crystalline varieties of an iron-nickel alloy (Taenite and Kamacite with 90-95 % iron and 8% nickel), the pieces of meteorite recovered from the area have fascinated world scientists.
Radiometric dating places the iron-nickel metal at 4 billion years.
The Gibeon Meteorite specimens range in size from one ton to just a few grams and are believed to be the fragments of one large body that might have weighed about 15 tons, measuring roughly 4x4x1,5 meters when it entered the atmosphere. The chemical composition of the 77 pieces found is almost similar, and the texture of their surface indicates the moment at which the body fragmented.
It has been calculated that the meteorite body must have entered the Earth's atmosphere along a northwesterly trajectory and at a low angle of 10` to 20` from the horizon. The molecules that form the atmosphere cause a resistance that slows down the meteorite and melts the outer surface. The varieties of thermal and shock-induced microstructures of the Gibeon Meteorites are the greatest in the world an only matched by the Canyon Diablo Meteorite of northern Arizona." (source: Namibweb.com http://www.namibweb.com/gibeon.htm)
Before the First World War, between 1911 and 1913, the German colonial administration tried to collect and map all the meteorite pieces that were left in the Gibeon area.
Some were given to museums and scientists abroad, but 33 pieces between 195 kg and 555 kg can still be visited in Windhoek, either at the museum of the Geolocical Survey or at the Gibeon Fountain display in Post Street Mall, also known locally as Town Square.
This area is a pedestrian zone, so note that there is no direct parking access to the display!
But you may combine your visit there with a nice shopping tour, for there are loads of local handicraft items and curio on display around the fountain.
To log this earthcache, please answer the following questions:
1. Look for G3776 and and give a short description of the surface: is it smooth or rough and spiky, are there any sharp edges or fractures to be seen?
2. What do you think does this indicate for the moment of fragmentation: still in the atmosphere so that the different pieces where exposed to thermal alteration, or when the whole body hit the ground?
3. Each fragment has a little edge cut off, and here the interior of the body can be seen. Give a short description of this inner surface: shiny or rusty, smooth or rough?
4. Since the meteorites consist mainly of iron: what component do you think prevents corrosion?
Please send your answers VIA MAIL to nannibella (gerne auch auf Deutsch). Please do NOT use the new message center.
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HAVE FUN - IT MIGHT BE THE FIRST AND LAST TIME YOU TOUCH SOMETHING EXTRATERRESTRIC!
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