A 50-year record of NO x and SO 2 sources in precipitation in the Northern Rocky Mountains, USA

• Published in: Geochemical Transactions
• Main Authors: Schuster Paul F, Naftz David L, Johnson Craig A
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2011
• Subjects: Environmental sciences; GE1-350; Chemistry; QD1-999; ice core
• Online Access: https://doi.org/10.1186/1467-4866-12-4; https://doaj.org/article/26eaf31d037a4cbfb281dcc7e5980422

Abstract 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 15 N, <graphic file="1467-4866-12-4-i1.gif"/> ) and sulfur (δ 34 S, <graphic file="1467-4866-12-4-i2.gif"/> ), as well as <graphic file="1467-4866-12-4-i1.gif"/> and <graphic file="1467-4866-12-4-i2.gif"/> 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 34 S value in the UFG ice-core samples coincided with snow deposited during the 1980 eruption of Mt. St. Helens, Washington. The remaining δ 34 S values were similar to the isotopic composition of coal from southern Wyoming. The δ 15 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 15 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.