Allende (meteorite)
The Allende meteorite is a stone meteorite that entered the earth's atmosphere over Mexico in the early morning of February 8, 1969 .
As a result of the frictional heat and the shock-like deceleration, the meteorite burst as a bright ball of fire in the atmosphere. Numerous fragments fell as showers over an area of 10 km × 50 km. A larger piece narrowly missed the post office of the town of Pueblito de Allende ( state of Chihuahua ), after which the meteorite was named. The total mass of the meteorite is estimated at 5 t; around 3 t have been collected so far and are in museums, institutes and privately owned.
classification
The Allende meteorite belongs to the class of carbonaceous chondrites . In addition to clearly visible chondrules, it shows inclusions of high temperature minerals as well as calcium and aluminum-rich materials ( CAI ), which are considered to be the first solid and oldest material in the solar system . The CAIs contain microdiamonds that were apparently formed outside the solar system during the explosion of a nearby supernova. This is indicated by the unusual isotope ratios of the elements krypton , xenon and nitrogen in diamonds. In addition, the Allende meteorite contains decay products of the aluminum isotope Al-26, which can only arise in a supernova explosion. The pressure waves released during the star explosion could have condensed the pre- solar nebula and thus set the formation of the solar system in motion.
The Allende meteorite comes from the asteroid belt and is classified as a carbonaceous chondrite of group CV3. Chemical composition: 23.6% iron ; 15.9% silicon ; 14.9% magnesium ; 1.9% calcium ; 1.7% aluminum ; 1.2% nickel ; 0.5% carbon ; 0.35% chromium ; 0.15% manganese ; 0.11% phosphorus ; 0.09% titanium ; 0.0093% vanadium ; organic compounds (in traces) such as alkanes , amino acids
Mineral finds
In the Allende meteorite numerous minerals could be detected, although with the Amphibolvertreter Tschermakit , the feldspar anorthite and nepheline , the grenades Andradite and Grossular , the olivine fayalite , forsterite and Kirschsteinite , the pyroxene augite (in the variety Fassait ) Hedenbergit , Kushiroit and wollastonite as well as melilite , rhoenite and sodalite the silicates predominate.
Other finds include the elements carbon (as diamond ) and rhenium ; the sulfides pentlandite and troilite ; the oxides hibonite , ilmenite , kamiokite , corundum , magnetite , perovskite , spinel , tazheranite and tugarinovite as well as the phosphate merrillite .
The Allende meteorite is also type locality for nine minerals so far:
- 2007: Allendeit , hexamolybdenum , monipit named after the meteorite
- 2008: Davisite , Grossmanit , Tistarit
- 2009: Hibonite- (Fe) ( IMA 2009-027 )
- 2010: Panguit
- 2011: Kangit
- 2017: rubinite
