Fig. 4. Measured δ³⁴S and Δ³³S, and estimated volcanic (background corrected) δ³⁴S and Δ³³S with continuous nssS concentrations.

Background correction is applied when volcanic sulfate accounts for over 60 % (f_volc > 0.60). Solid line at Δ³³S = 0 ‰. Dashed lines indicate Δ³³S ± 0.09 bracketing range of S-MIF signals. Error bars represent 2σ uncertainty.