Multiple Sulfur Isotopic Composition of Main Group Pallasites Support Genetic Links to IIIAB Iron Meteorites

James W. Dottin III, James Farquhar, Jabrane Labidi

Geochimica et Cosmochimica Acta
In Press, Accepted Manuscript, Available online 31 January 2018


“This study reports the quadruple sulfur isotope composition of troilite nodules from Main Group Pallasites. Values range from -0.23‰ to 0.34‰ (average = 0.03±0.17‰ S.D.) in δ34S and 0.008‰ to 0.025‰ (average = 0.018± 0.006‰ S.D.) in Δ33S and -0.38 to -0.01 (average = -0.17±0.11‰ S.D.) in Δ36S. The variance of these analyses is comparable to estimates of analytical uncertainty (±0.3‰, ± 0.008‰, and ±0.3‰, for δ34S, Δ33S, and Δ36S, respectively) and the average of these values is taken as a constraint on the composition of sulfur in the MG Pallasite parent body. The different Δ33S value compared to CDT and IAB iron meteorites at a similar δ34S value is interpreted as a mass-independent signature. This signature is similar in magnitude and direction to previously published values observed in IIIAB iron meteorites, further supporting a genetic relationship between the two groups of meteorites.”