HR: 1340h
AN: A53B-1153    [Abstracts]
TI: Recent Deposition of Trace Metals to Central (Summit) Greenland as Recorded in 3-Meter Snow Pits
AU: * Overdier, J
EM: overdier@facstaff.wisc.edu
AF: Environmental Chemistry and Technology Program University of Wisconsin-Madison, 660 North Park Street, Madison, WI 53706, United States
AU: Shafer, M
EM: mmshafer@wisc.edu
AF: Environmental Chemistry and Technology Program University of Wisconsin-Madison, 660 North Park Street, Madison, WI 53706, United States
AU: Schauer, J
EM: jschauer@engr.wisc.edu
AF: Environmental Chemistry and Technology Program University of Wisconsin-Madison, 660 North Park Street, Madison, WI 53706, United States
AU: von Schneidemesser, E
EM: evonschneide@wisc.edu
AF: Environmental Chemistry and Technology Program University of Wisconsin-Madison, 660 North Park Street, Madison, WI 53706, United States
AU: Hagler, G
EM: gswhagler@gmail.com
AF: Civil and Environmental Engineering Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332, United States
AU: Bergin, M
EM: mike.bergin@ce.gatech.edu
AF: Civil and Environmental Engineering Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332, United States
AB: During the summer 2005 and 2006 field seasons at Summit (3270 m) Greenland we collected snow core samples for comprehensive geochemical characterization. This sampling effort was one facet of our larger program with the overall objective of improving our understanding of the sourcing and post depositional diagenesis of organic carbon depositing on the Greenland ice sheet. From snow pits of 3-meter depth, representing ~4 years of recent accumulation, detailed profiles of a suite of chemical variables were obtained, including: total and water soluble organic carbon, particulate organic and elemental carbon, inorganic ions, and comprehensive elemental and isotopic analysis. The elemental characterization supports our source reconciliation efforts in providing sub-seasonal data on aerosol particulate matter chemistry from which sourcing vectors can be inferred. Elemental and isotopic analyses on the melted snow cores were carried-out using high-resolution (sector-field) ICP-MS (Finnegan Element 2). A large suite of elements were quantified, including: the major/crustal elements (Al, Ca, K, Fe. Na, Mg, Si), minor crustal elements (Ba, Cs, Li, Rb, Sc, Sr, Ti) light transition metals (Co, Cr, Cu, Mn, Ni, Zn), heavy transition metals (Ag, Cd, Hg, Pb, Tl, W), oxyanion metals (As, Mo, U, V), platinum group metals (Rh, Pd, Pt), rare earths (Ce, Er, Eu, La, Nd, Sm, Y, Yb), as well as, Be, Sb, Sn, sulfur and phosphorus. Very large (>30x) temporal variation in snow core concentrations were measured for Al, Ba, Cr, Cu, Fe, Mg, P, Rb, Sr, Ti, U, Zn and all the rare earths, while low variation (~5x) is observed for the elements As, Cd, Hg, Mo, S and Sn. The later group is representative of the more mobile, anthropogenically dominated/sourced trace metals. Principal crustal elements (Al, Ca, Fe, K, Mg, Na) and sulfate (S) present similar profiles, with significant burial peaks in spring. Major burial peaks are relatively uniformly spaced (~70 cm apart), indicating some consistency in net snow accumulation rates and transport vectors. A large suite of trace elements (Cd, Mn, Ni, P, Pb, Pt, Ti, U) and most rare earths exhibit deposition patterns similar to that of the crustals and S. However, the burial patterns of several elements (Cu, Hg, Sn, Zn) are unique. The Hg profile exhibits summer peaks and is anti-correlated with most other elements, but is correlated with TOC. TOC is, in general though, poorly correlated with most elements, indicating that post-depositional diagenesis may be significant for carbon.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0317 Chemical kinetic and photochemical properties
DE: 0365 Troposphere: composition and chemistry
DE: 0399 General or miscellaneous
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting