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NUMBER 19 79
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FIGURE 6.—Photomicrograph of thin section of the Mirzapur, L5 veined intermediate chondrite
(see text). Note the black, opaque, shock veins and shock altered areas in the center. The
chondrules are quite distinct, although often deformed in some parts. Length of section,
—20 mm.
the modal residue. Because the residue in the
modal analyses (Table 3) is substantial, an attempt
has been made to establish its chemical composition
by deducting the components of the modal minerals
and normative metal, sulfide, chromite,
ilmenite, and apatite from the bulk analyses. The
compositions of these residues are compared to the
bulk silicates in Table 4. Although this modal
residue is largely due to overlap between grains
in the probe analysis, it appears that in all cases
except for Atarra, the residue has 1-3% normative
corundum (A12O3) and more iron-rich, including
Atarra, normative olivine than the bulk silicates.
Thus all these L-chondrites appear to have small
amounts of a matrix component enriched in Al
and Fe, similar to the H-chondrites previously
described by Fredriksson, et al. (1975). Moreover,
the comparison in Table 5 of the bulk silicate