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We have “mapped” carbon concentrations in a 4.2 × 4.2 mm area of the Ailende meteorite with the 12C(d,p)13 C nuclear method. The x,y resolution perpendicular to the deuteron beam was 65 μm; the depth resolution was 0.6 μm. The matrix of the meteorite contains about 1 wt % carbon, which is uniformly distributed at the 65‐μm level of resolution. The matrix contains most, perhaps close to all, C of this meteorite. The coarse‐grained constituents, such as chondrules, show a very strong enhancement of C in the depth range 2 to about 0 μm; the matrix does not show this enhancement. The enhancement may be due to contamination of the coarse‐grained areas or else to migration of C in solid solution from the interiors of comparatively large crystals to their freshly polished surfaces.

Carbon contents of three Dark Inclusions (DI's) of the Allende meteorite, measured chemically, range from 0.56 to 1.17 weight %. When one includes the data reported by Bunch, Chang, and Ott (two DI's), the lower limit is 0.44%. The C‐concentration map of a 1.6 × 1.6 mm2 area straddling the boundary of a DI and matrix, or else of a DI and its dark halo, obtained with a 12C (d,p)13 C nuclear microprobe, shows that the C‐content of the core of the DI is very uniform, and that the C‐content of the rim is 2.9 ± 0.3 times larger. Variability of C‐content of matrix and matrix‐like areas of Allende appears to be the rule. DI's cannot be reworked bulk Allende, or precursor for bulk Allende without the addition, respectively removal of significant amounts of carbon. However, some Type 1 DI's might be reworked Allende matrix or precursor matter for that matrix.

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