| Summary: | <p>Abstract</p> <p>Ice-core samples from Upper Fremont Glacier (UFG), Wyoming, were used as proxy records for the chemical composition of atmospheric deposition. Results of analysis of the ice-core samples for stable isotopes of nitrogen (δ<sup>15</sup>N, <inline-formula><graphic file="1467-4866-12-4-i1.gif"/></inline-formula>) and sulfur (δ<sup>34</sup>S, <inline-formula><graphic file="1467-4866-12-4-i2.gif"/></inline-formula>), as well as <inline-formula><graphic file="1467-4866-12-4-i1.gif"/></inline-formula> and <inline-formula><graphic file="1467-4866-12-4-i2.gif"/></inline-formula> deposition rates from the late-1940s thru the early-1990s, were used to enhance and extend existing National Atmospheric Deposition Program/National Trends Network (NADP/NTN) data in western Wyoming. The most enriched δ<sup>34</sup>S value in the UFG ice-core samples coincided with snow deposited during the 1980 eruption of Mt. St. Helens, Washington. The remaining δ<sup>34</sup>S values were similar to the isotopic composition of coal from southern Wyoming. The δ<sup>15</sup>N values in ice-core samples representing a similar period of snow deposition were negative, ranging from -5.9 to -3.2 ‰ and all fall within the δ<sup>15</sup>N values expected from vehicle emissions. Ice-core nitrate and sulfate deposition data reflect the sharply increasing U.S. emissions data from 1950 to the mid-1970s.</p>
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