We purchased a 22.8 gram slice of an NWA meteorite in 2007 at the Sainte-Marie-aux-Mines mineral and gem show. For some unknown reason it entered our collection with an incorrect NWA number, a mystery yet to be solved. Looking at the thin sections that we had made, it very well could be an LL3 as our notes show. LL chondrites have the largest mean diameter chondrules among ordinary chondrites. Those in our sample range from 3mm to under a quarter millimeter in apparent diameter.
The two sections photographed here. Transmitted white light.
The top portion of the first section in cross-polarized light, XPL. The field of view, FOV, is 15mm wide.
A particularly large chondrule composed of a variety of mineral grains and chondrule fragments. FOV=3.6mm
Porphyritic chondrule about 3mm long.
Polysomatic barred chondrule with thin bars, 3mm wide.
Similar texture to above. FOV=3.1mm
Cryptocrystalline chondrule. FOV=3.1mm
Several masses of small adjoining cryptocrystalline cells. FOV=3.1mm
FOV=3.1mm
This chondrule appears to have formed around the central violet skeletal crystal. FOV=3.1mm
This mass of crystals appears to have had two or three growth episodes with later growth extending the earlier crystal orientations – epitaxy. FOV=3.1mm
Similar to above, the radial forms at center appear to have extended in stages. FOV=3.1mm
A closeup of the radial forms. FOV=1.2mm. Plane polarized light.
A small chondrule. FOV=3.1mm
That granular chondrule is 0.25mm wide.
Another small granular chondrule.
It is 0.17mm in apparent diameter. (It would have appeared larger if the section had cut through a thicker portion, if one existed.)
Individual dusty olivine grains in chondrules contain fine metallic iron inclusions formed by a reduction process before the grain was incorporated into the chondrule. (Sometimes all grains in a chondrule are dusty.) Here the subject grain is difficult to see at this scale. There is a void to the right of the dusty grain.
The dusty blue relict grain. There is a void to the right. FOV=0.4mm
A bright relict grain in the center of a chondrule. FOV=3.1mm
FOV=0.5mmChond=0.25mmwideP1000.jpg)
MDia=0.17mmP1000U.jpg)
FOV=5.2mmP1000.jpg)
