Table_1_Stable Isotopes of Nitrate, Sulfate, and Carbonate in Soils From the Transantarctic Mountains, Antarctica: A Record of Atmospheric Deposition and Chemical Weathering.XLSX

• Main Authors: Melisa A. Diaz, Jianghanyang Li, Greg Michalski, Thomas H. Darrah, Byron J. Adams, Diana H. Wall, Ian D. Hogg, Noah Fierer, Susan A. Welch, Christopher B. Gardner, W. Berry Lyons
• Format: Dataset
• Language: unknown
• Published: 2020
• Subjects: Solid Earth Sciences; Climate Science; Atmospheric Sciences not elsewhere classified; Exploration Geochemistry; Inorganic Geochemistry; Isotope Geochemistry; Organic Geochemistry; Geochemistry not elsewhere classified; Igneous and Metamorphic Petrology; Ore Deposit Petrology; Palaeontology (incl. Palynology); Structural Geology; Tectonics; Volcanology; Geology not elsewhere classified; Seismology and Seismic Exploration; Glaciology; Hydrogeology; Natural Hazards; Quaternary Environments; Earth Sciences not elsewhere classified; Evolutionary Impacts of Climate Change; Antarctica; geochemistry; salts; stable isotopes; nitrate; sulfate; carbonate; Antarctic; McMurdo Dry Valleys; East Antarctic Ice Sheet; Shackleton; Transantarctic Mountains; Shackleton Glacier; Antarc*; Ice Sheet
• Online Access: https://doi.org/10.3389/feart.2020.00341.s001; https://figshare.com/articles/dataset/Table_1_Stable_Isotopes_of_Nitrate_Sulfate_and_Carbonate_in_Soils_From_the_Transantarctic_Mountains_Antarctica_A_Record_of_Atmospheric_Deposition_and_Chemical_Weathering_XLSX/12871568

Soils in ice-free areas in Antarctica are recognized for their high salt concentrations and persistent arid conditions. While previous studies have investigated the distribution of salts and potential sources in the McMurdo Dry Valleys, logistical constraints have limited our investigation and understanding of salt dynamics within the Transantarctic Mountains. We focused on the Shackleton Glacier (85° S, 176° W), a major outlet glacier of the East Antarctic Ice Sheet located in the Central Transantarctic Mountains (CTAM), and collected surface soil samples from 10 ice-free areas. Concentrations of water-soluble nitrate (NO 3 – ) and sulfate (SO 4 2– ) ranged from <0.2 to ∼150 μmol g –1 and <0.02 to ∼450 μmol g –1 , respectively. In general, salt concentrations increased with distance inland and with elevation. However, concentrations also increased with distance from current glacial ice position. To understand the source and formation of these salts, we measured the stable isotopes of dissolved water-soluble NO 3 – and SO 4 2– , and soil carbonate (HCO 3 + CO 3 ). δ 15 N-NO 3 values ranged from −47.8 to 20.4‰ and, while all Δ 17 O-NO 3 values are positive, they ranged from 15.7 to 45.9‰. δ 34 S-SO 4 and δ 18 O-SO 4 values ranged from 12.5 and 17.9‰ and −14.5 to −7.1‰, respectively. Total inorganic carbon isotopes in bulk soil samples ranged from 0.2 to 8.5‰ for δ 13 C and −38.8 to −9.6‰ for δ 18 O. A simple mixing model indicates that NO 3 – is primarily derived from the troposphere (0–70%) and stratosphere (30–100%). SO 4 2– is primarily derived from secondary atmospheric sulfate (SAS) by the oxidation of reduced sulfur gases and compounds in the atmosphere by H 2 O 2 , carbonyl sulfide (COS), and ozone. Calcite and perhaps nahcolite (NaHCO 3 ) are formed through both slow and rapid freezing and/or the evaporation/sublimation of HCO 3 + CO 3 -rich fluids. Our results indicate that the origins of salts from ice-free areas within the CTAM represent a complex interplay of atmospheric deposition, chemical ...