[meteorite-list] REport: Minerals in Allende Meteorite

[MARK BOSTICK]

Your welcome Harlan,

My original post did not go through, so for benifit of the group I am 
reposting.  I think this gives a very good, not too technical answer to what 
is in Allende.

Smithsonian Contributions to the Earth Sciences
SCES-5, The Allende, Mexico, Meteorite Shower

Roy S. Clarke, Jr., Eugene Jarosewich, Brian Mason, Joseph Nelen, Manuel 
Gomez and Jack R. Hyde

Issue Date: February 17, 1971

"Chemical and mineralogical compositions establish that Allende is a Type 
III carbonaceous chondrite. Three distinct components can be recognized: 
finegrained black matrix (~60%), chondrules (~30%), and irregular white 
aggregates (~10%). The matrix consists almost entirely of iron-rich olivine 
(average 50% Fe2SiO4), with minor amounts of troilite, pentlandite, and 
taenite, rendered opaque by dispersed carbonaceous material. Most of the 
chondrules are magnesium-rich, and consist of olivine (average 9% Fe2SiO4) 
with minor amounts of clinoenstatite and some glass; a few chondrules are 
rich in calcium and aluminum, and are made up largely of anorthite, 
gehlenite, augite, and spinel. The irregular aggregates are also rich in 
calcium and aluminum, and contain anorthite, gehlenite, augite, spinel, 
nepheline, grossular, and sodalite (the last two minerals have not 
previously been recorded from meteorites). Complete chemical analyses have 
been made of the bulk meteorite, a dark inclusion, the matrix, a chondrule 
concentrate, two individual chondrules, and a single aggregate."

Clear Skies,
Mark Bostick
www.meteoritearticles.com