FIG. 1.

Total ion current chromatograms of the gaseous products released during individual heating experiments of samples of a natural jarosite clay and a lab standard of ferric sulfate hydrate at 600°C and 1000°C. The m/z 28 peak is labeled as CO?, as it could be either carbon monoxide or nitrogen; we infer carbon monoxide as discussed in the text. Very minor peaks for oxygen and carbon dioxide were present in the ferric sulfate hydrate experiment at 600°C but cannot be seen at the scale of the figure. All chromatograms are presented at the same scale.