Allende meteorite

With the meteorite Allende is a stone meteorite entered the Earth's atmosphere in the early morning of February 8, 1969 via Mexico.

As a result of frictional heat and the shock-like deceleration of the meteor burst still in the atmosphere as a bright fireball. Numerous fragments left as rain on an area of ​​10 km × 50 km down. A larger piece just missed the post office of the place of Pueblito de Allende ( Chihuahua state ), after the meteorite got its name. The total mass of the meteorite is estimated to be 5 t; about 3 tonnes have so far been collected and are in museums, institutions and private property.

Classification

The Allende meteorite belongs to the class of carbonaceous chondrites. He has, in addition clearly visible chondrules inclusions of high-temperature minerals, calcium and aluminum rich materials ( CAI), which are regarded as the first weaning and oldest material in the solar system. The CAIs contain micro- diamonds that are obviously originated outside our solar system in the explosion of a nearby supernova. This is suggested by the unusual isotope ratios of the elements krypton, xenon and nitrogen back into the diamond. In addition, contains the Allende meteorite decay products of the aluminum isotope Al- 26, which can only occur in a supernova explosion. The liberated in the stellar explosion pressure waves could the pre-solar nebula condensed and thus have placed the formation of our solar system in motion.

The Allende meteorite comes from the asteroid belt and is einklassifiziert as CV3 carbonaceous chondrite group. 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; 900 ppm of titanium; 93 ppm vanadium; organic compounds ( in trace amounts ), such as alkanes, amino acids

Mineral discoveries

In the Allende meteorite numerous minerals could be detected, although with the Amphibolvertreter tschermakite, the feldspar anorthite and nepheline, andradite and grossular garnets, the olivines fayalite, forsterite and Kirschsteinite, the pyroxene augite ( in the variety Fassait ), hedenbergite, Kushiroit and wollastonite and melilite, Rhönit and sodalite the silicates predominate.

Other discoveries include the elements of diamond and rhenium; the sulphides pentlandite and troilite; the oxides hibonite, ilmenite, Kamiokit, corundum, magnetite, perovskite, spinel, and Tazheranit Tugarinovit and the phosphate Merrillit.

The Allende meteorite is also type locality for nine existing minerals:

• 2007: named after the meteorite Allendeit, Hexamolybdän, Monipit
• 2008: Davisit, Grossmanit, Tistarit
• 2009: hibonite - (Fe) (IMA 2009-027 )
• 2010: Panguit
• 2011: Kangit