Early inner solar system origin for anomalous sulfur isotopes in differentiated protoplanets

Michael A. Antonelli, Sang Tae Kim, Marc Peters, Jabrane Labidi, Pierre Cartigny, Richard J. Walkera, James Lyons, Joost Hoek, James Farquhar

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


Achondrite meteorites have anomalous enrichments in 33S, relative to chondrites, which have been attributed to photochemistry in the solar nebula. However, the putative photochemical reactions remain elusive, and predicted accompanying 33S depletions have not previously been found, which could indicate an erroneous assumption regarding the origins of the 33S anomalies, or of the bulk solar system S-isotope composition. Here, we report wellresolved anomalous 33S depletions in IIIF iron meteorites (<.0.02 per mil), and 33S enrichments in other magmatic iron meteorite groups. The 33S depletions support the idea that differentiated planetesimals inherited sulfur that was photochemically derived from gases in the early inner solar system (<∼2 AU), and that bulk inner solar system S-isotope composition was chondritic (consistent with IAB iron meteorites, Earth, Moon, and Mars). The range of mass-independent sulfur isotope compositions may reflect spatial or temporal changes influenced by photochemical processes. A tentative correlation between S isotopes and Hf-W core segregation ages suggests that the two systems may be influenced by common factors, such as nebular location and volatile content.

Original languageEnglish (US)
Pages (from-to)17749-17754
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number50
StatePublished - Dec 16 2014


  • Iron meteorites
  • Photochemistry
  • Protoplanetary disk
  • Solar system
  • Sulfur isotopes

ASJC Scopus subject areas

  • General


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