We present the first sulfur and oxygen isotopic data for tephra from the catastrophic 1883 eruption of Krakatau. Sulfur
isotopic ratios in unaltered Krakatau tephra erupted August 26–27, 1883 are markedly enriched in 34S relative to mantle
sulfur. High 34S values of C6:3 to C16:4‰ can best be explained by open-system or multi-stage degassing of SO2 from
the oxidized rhyodacitic and gray dacitic magmas with 34S enrichment of SO2