The objectives of this study are: (1) to investigate experimentally how thiosulfate and polythionates form through sulfur-water interaction (T>100oC), (2) to determine experimentally the thermal stabilities of thiosulfate and polythionates, (3) to determine experimentally the catalytic effects of mineral surfaces (pyrite and quartz) and trace levels of Fe2+(aq) on (1) and (2), and (4) to determine the sulfur speciation in several sulfur-rich hot springs in Yellowstone National Park in situ. Objectives are achieved through a combination of experimental work in the hydrothermal laboratory and field work in collaboration with the U.S.G.S. Ion Chromatographic techniques will be used for the in situ analysis of sulfur species, the PI will again collaborate with Kirk Nordstrom, and use a mobile, U.S.G.S. laboratory equipped with an IC identical to the one in the PI's lab. The results of these experiments will be used to identify natural hydrothermal solutions that could contain sulfur oxyanions in significant concentrations.
