Sulfur Isotopic Compositions of Sulfides from the Huronian Supergroup, Ontario, Canada

Abstract

Mass-independent isotopic fractionation (MIF) in sulfur isotopes from sedimentary rocks older than 2.5 Gyr has been attributed to the low oxygen content of the atmosphere. The Huronian Supergroup of Canada was deposited between 2.45-2.22Ga preserves a record of three glaciations. Small MIFs of sulfur have been reported in bulk analyses of sulfides from the Huronian Supergroup. We have started in-situ analyses of the sulfur isotopic compositions of sulfides for the Huronian Supergroup using ion microprobe. Our preliminary analyses show that sulfides from Pecors, Missisagi, Bruce, Espanola, Gowganda, and Gordon Lake Formations appear to have very small MIFs that are consistent with the previous work.