Multiple sulfur isotopic composition of main group pallasites support genetic links to IIIAB iron meteorites

摘要

This study reports the quadruple sulfur isotope composition of troilite nodules from Main Group Pallasites. Values range from -0.23 parts per thousand to 0.34 parts per thousand (average = 0.03 +/- 0.17 parts per thousand S.D.) in delta S-34 and 0.008 parts per thousand to 0.025 parts per thousand (average = 0.018 +/- 0.006 parts per thousand S.D.) in Delta S-33 and -0.38 to -0.01 (average = -0.17 +/- 0.11% S. D.) in Delta S-36. The variance of these analyses is comparable to estimates of analytical uncertainty (+/- 0.3 parts per thousand, +/- 0.008 parts per thousand, and +/- 0.3 parts per thousand, for delta S-34, Delta S-33, and Delta S-36, 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 Delta S-33 value compared to CDT and IAB iron meteorites at a similar delta S-34 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. (C) 2018 Elsevier Ltd. All rights reserved.