Allende
History

Name: Allende
Location: Chihuahua, Mexico
Type: Carbonaceous Chondrite, Type III CV3

The year 1969 was an extraordinary year for meteorite showers of rare vintage. It all began in the dead
of night over the little north-central Mexican town of Pueblito de Allende in the state of Chihuahua. At 1;05 A.M. on
February 8, a brilliant fireball appeared,lighting the landscape for miles. The single body producing the fireball
apparently disrupted high in the atmosphere and continued to fall, still burning, as many individual fragments. (Many of
the specimens display a secondary fusion crust, indicating breakage while still incandescent.) After reaching their
retardation points, they fell by gravity and were subject to prevailing wings. They fell over a strewn field with its long
axis extending for 30 miles along a south-southwest to north-northeast direction, possibly exceeding 180 square miles in
area. This is the largest strewn field ever investigated. Predictably, the largest masses fell at the far north-northeast
end of the strewn field. A specimen weighing over 240 pounds that had shattered into many smaller pieces on impact was
found at this point. More than 2 tons of meteoritic material was recovered in the first few weeks after the fall. Meteorites
are still being found in and around the strewn field even after twenty years of searching. Allende takes the prize as the
largest carbonaceous meteorite fall in history. Carbonaceous chondrites are the most primitive chondrites, having undergone
the least amount of mixing and re-melting since the solar system's formation. It also has the largest strewn field area known.
The Allende meteorites turned out to be rare Type CV3 carbonaceous chondrites. Among other things, they contain curious,
irregular white inclusions of an aluminum-calcium-titanium mineral that may represent the first silicate minerals to have
condensed out of the solar nebula five billion years ago. More Type CV3 material was recovered from this fall than was known
in all the world before 1969.