Along with our colleague, Dr. Huiming Bao at LSU, we are modeling the origin and transport history of soil-salts in the Dry Valleys. This salt repository offers an opportunity to study atmospheric chemistry (past and present), the origin and transport of ions in soils, the weathering activity of soils, and post depositional soil-leaching processes/ cryoturbation within this unique environment. Our most recent work has focused on the distribution, concentration, and isotopic signature of chloride and sulfate in Dry Valley soils. We test a hypothesis that soil sulfate in the Dry Valleys is a predictable mixture of three major components: sea-salt sulfate, non-sea-salt sulfate, and background sulfate (derived from weathering and volcanic sources) that to a large extent, varies as a function of elevation and distance from the coast. By measuring sulfate’s three stable isotope parameters, i.e., D17O, d18O, and d34S, plus estimating independently the end-member stable isotope parameters for the three components on the basis of published reports and our measured data, we solve explicitly the mixing proportion for each component using a set of three simultaneous linear equations. For Cl studies, one result is that sublimation tills in the SUZ have their Cl input from two boundaries: a till-atmosphere interface at the top and a buried-ice-till interface at the bottom, differing distinctively from basal tills where there is no salt contribution from the bottom.
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