Paul F. Schuster Craig A. Johnson David L. Naftz 2011 <p><span>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</span>¹⁵<span>N,&nbsp;</span><img src="https://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1467-4866-12-4/MediaObjects/12932_2010_Article_115_IEq1_HTML.gif" alt="" data-mce-src="https://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1467-4866-12-4/MediaObjects/12932_2010_Article_115_IEq1_HTML.gif"><span>) and sulfur (δ</span>³⁴<span>S,&nbsp;</span><img src="https://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1467-4866-12-4/MediaObjects/12932_2010_Article_115_IEq2_HTML.gif" alt="" data-mce-src="https://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1467-4866-12-4/MediaObjects/12932_2010_Article_115_IEq2_HTML.gif"><span>), as well as&nbsp;</span><img src="https://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1467-4866-12-4/MediaObjects/12932_2010_Article_115_IEq1_HTML.gif" alt="" data-mce-src="https://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1467-4866-12-4/MediaObjects/12932_2010_Article_115_IEq1_HTML.gif"><span>&nbsp;and&nbsp;</span><img src="https://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1467-4866-12-4/MediaObjects/12932_2010_Article_115_IEq2_HTML.gif" alt="" data-mce-src="https://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1467-4866-12-4/MediaObjects/12932_2010_Article_115_IEq2_HTML.gif"><span>&nbsp;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</span>³⁴<span>S value in the UFG ice-core samples coincided with snow deposited during the 1980 eruption of Mt. St. Helens, Washington. The remaining δ</span>³⁴<span>S values were similar to the isotopic composition of coal from southern Wyoming. The δ</span>¹⁵<span>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</span>¹⁵<span>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.</span></p> application/pdf 10.1186/1467-4866-12-4 en Springer A 50-year record of NOx and SO2 sources in precipitation in the Northern Rocky Mountains, USA article