Sulfur isotopic composition of Fe-Ni sulfide grains in CI and CM carbonaceous chondrites

Bullock, Emma S.; McKeegan, Kevin D.; Gounelle, Matthieu; Grady, Monica M. and Russell, Sara S. (2010). Sulfur isotopic composition of Fe-Ni sulfide grains in CI and CM carbonaceous chondrites. Meteoritics & Planetary Science, 45(5) pp. 885–898.

DOI: https://doi.org/10.1111/j.1945-5100.2010.01052.x

Abstract

In situ secondary ion mass spectrometry analyses of ³²S, ³³S, and ³⁴S in iron-nickel sulfide grains in two CI1 chondrites and six CM chondrites were performed. The results show a wider range of both enrichment and depletion in δ³⁴S relative to troilite from the Canyon Diablo meteorite (CDT) than has been observed in previous studies. All data points lie within error of a single mass dependent fractionation line. Sulfides from CI1 chondrites show δ³⁴SCDT from -0.7 to 6.8‰, while sulfide grains in the CM1 chondrite are generally depleted in heavy sulfur relative to CDT (δ³⁴S from -2.9 to 1.8‰). CM2 chondrites contain sulfide grains that show enrichment and depletion in ³⁴S (δ³⁴SCDT from -7.0 to 6.8‰). Sulfates forming from sulfide grains during aqueous alteration on the chondrite parent body are suggested to concentrate light sulfur, leaving the remaining sulfide grains enriched in the heavy isotopes of sulfur. The average degree of enrichment in ³⁴S in CM chondrite sulfides is broadly consistent with previously suggested alteration sequences.

Viewing alternatives

Metrics

Item Actions

Export

You can export this page using these formats Digital Object Identifier - DOI