Mass-independent isotope effects in Archean (2.5 to 3.8 Ga) sedimentary sulfides determined by ion microprobe analysis
نویسندگان
چکیده
We report sulfur isotope anomalies with S, the deviation from a mass-dependent fractionation line for the three-isotope system (S/S vs. S/S), ranging up to 2‰ within individual Archean sedimentary sulfides from a variety of localities. Our measurements, which are made in situ by multicollector secondary ion mass spectrometry, unequivocally corroborate prior bulk measurements of mass-independent fractionations (MIF) in sulfur and provide additional evidence for an anoxic atmosphere on the Earth before 2 Ga. This technique also offers new opportunities for exploring ancient sulfur metabolisms preserved in the rock record. The presence of MIF sulfur in sulfides from a 3.8-Ga Fe-rich quartzite from Akilia (island), West Greenland, is consistent with a marine sedimentary origin for this rock. Copyright © 2003 Elsevier Science Ltd
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