Gibeon (meteorite)
Encyclopedia
Gibeon is a meteorite
Meteorite
A meteorite is a natural object originating in outer space that survives impact with the Earth's surface. Meteorites can be big or small. Most meteorites derive from small astronomical objects called meteoroids, but they are also sometimes produced by impacts of asteroids...

 that fell in prehistoric times in Namibia
Namibia
Namibia, officially the Republic of Namibia , is a country in southern Africa whose western border is the Atlantic Ocean. It shares land borders with Angola and Zambia to the north, Botswana to the east and South Africa to the south and east. It gained independence from South Africa on 21 March...

. It was named after the nearest town: Gibeon, Namibia.

History

The meteorite was discovered by the Nama people
Namaqua
Nama are an African ethnic group of South Africa, Namibia and Botswana. They traditionally speak the Nama language of the Khoe-Kwadi language family, although many Nama now speak Afrikaans. The Nama are the largest group of the Khoikhoi people, most of whom have largely disappeared as a group,...

 and used by them to make tools and weapons.

In 1836 the English captain J. E. Alexander collected samples of the meteorite in the vicinity of the Great Fish River
Great Fish River
The Great Fish River is a river running through the South African province of the Eastern Cape, it originates east of Graaff-Reinet and runs through Cradock, just south of this the Tarka River joins it...

 and sent them to London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

. There John Herschel
John Herschel
Sir John Frederick William Herschel, 1st Baronet KH, FRS ,was an English mathematician, astronomer, chemist, and experimental photographer/inventor, who in some years also did valuable botanical work...

 analyzed them and confirmed for the first time the extraterrestrial nature of the material.

Strewn field

The fragments of the meteorite in the strewn field
Strewn field
The term strewnfield indicates the area where meteorites from a single fall are dispersed.It is also often used with tektites produced by large meteorite impact.-Formation:There are two strewnfield formation mechanisms:...

 are dispersed over an elliptical area 275km long and 100km wide.

Composition and classification

The term Gibeon encompasses the whole meteoritic material fallen from the sky during this fall. This material is classified as iron meteorite
Iron meteorite
Iron meteorites are meteorites that consist overwhelmingly of nickel-iron alloys. The metal taken from these meteorites is known as meteoric iron and was one of the earliest sources of usable iron available to humans.-Occurrence:...

 belonging to the chemical group IVA.

Gibeon meteorites are composed of an iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

-nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...

 alloy containing significant amounts of cobalt
Cobalt
Cobalt is a chemical element with symbol Co and atomic number 27. It is found naturally only in chemically combined form. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal....

 and phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...

. The crystal structure of this meteorite provides a classic example of fine octahedrite
Octahedrite
Octahedrites are a class of iron meteorites within the structural classification. They are the most common class of iron meteorites.They are composed primarily of the nickel-iron alloys: taenite - high nickel content, and kamacite - low nickel content....

 and the Widmanstatten pattern
Widmanstätten pattern
Widmanstätten patterns, also called Thomson structures, are unique figures of long nickel-iron crystals, found in the octahedrite iron meteorites and some pallasites. They consist of a fine interleaving of kamacite and taenite bands or ribbons called lamellæ...

is appreciated for its beauty both by collectors and designers of jewellry.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK