Bottrell, S. H. and Tranter, M. (2002)
Sulphide oxidation under partially anoxic conditions at the bed of the Haut Glacier d'Arolla, Switzerland
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- Hydrological Processes
- Oxygen isotopic data are presented for bulk glacial meltwaters draining the Haut Glacier d’Arolla, Valais, Switzerland and for the sulphate contained within them in an attempt to assess the redox status of the subglacial chemical weathering environment. The sulphate derived from subglacial chemical weathering is so depleted in 18O that it must have formed, at least partially, in an anoxic environment. Under these conditions, Fe3C can act as an oxidizing agent and oxygen atoms incorporated into sulphate are derived from 18O-depleted water molecules (by contrast, dissolved O2 is strongly enriched in 18O). These data therefore support the hypothesis that sectors of the glacier bed are anoxic and that Fe3C may act as a signiﬁcant oxidizing agent under these conditions.