lodranite
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A lodranite found at Graves Nunataks, Antarctica.
Dimensions: 10.5 x 8 x 5 cm. Mass: 949 g. The section shows an equigranular
aggregate (grains averaging 0.3 mm) of equal amounts of nickel-iron,
olivine, and pyroxene,
with a little plagioclase. Image
and description: Johnson Space Center
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A rare type of achondrite named after the
1 kg Lodran meteorite that fell in Punjab, Pakistan (29° 32' N, 71°
48' E) on Oct. 1,1868. To begin with, lodranites were considered to be stony-iron
meteorites because they contain stony components, notably olivine, orthopyroxene,
and minor plagioclase, and nickel-iron
alloy in roughly equal proportions. However,
since the discovery of the closely-related acapulcoite
group, the lodranites have been classified as primitive achondrites. The
similar mineralogy and oxygen isotope compositions of these two groups indicate
they may have originated on the same parent body, most likely an S-class
asteroid. Lodranites contain bigger crystals of olivine and pyroxene
and appear to have been subjected to greater heat than acapulcoites. This
suggests they came from deeper inside the parent body where they underwent
more intense thermal processing and a subsequent longer period of cooling.
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• METEORS
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