HR: 17:15h
AN: V12H-06    [PDF]
TI: Volcano emissions of trace metals, atmospheric deposition, and supply to biogeochemical cycles
AU: * Hinkley, T
EM: thinkley@usgs.gov
AF: U.S. Geological Survey, National Ice Core Lab,, Denver, co 80225 United States
AU: Thornber, C R
EM: cthornber@usgs.gov
AF: U.S. Geological Survey, Cascades Volcano Observatory, Vancouver, WA 98683 United States
AU: Matsumoto, A
EM: aki.matsumoto@aist.go.jp
AF: Deep Geological Environments Research Center, National Institute of Advanced Industrial Science and Technology Deep Geological Environments Research Center, National Institute of Advanced Industrial Science and Technology, Center 7, 1-1-1, Higashi, Ibaraki, Tsukuba, 305-8567 Japan AB: Quiescently degassing (not exploding) volcanoes inject into the troposphere plumes that have remarkably high concentrations of ordinarily-rare, volatile trace metals. In pre-industrial times, these emissions appear to have accounted for the strong "enrichments" (relative to concentrations in crustal material or in ocean solute) of many such trace metals in the material deposited from the atmosphere. This has been shown by measuring the source strength of the emissions of metals from volcanoes, and comparing that to the amounts of the metals (excess over amounts accounted for by rock dust and sea salt) deposited onto high-latitude ice sheets: volcano degassing outputs of metals and deposition masses of metals to ice are comparable, on the basis of the masses (fluxes) and proportions of the metals, and from the proportions of lead (Pb) isotopes. There is indication that in modern industrial times the elevated trace metal fractions in the atmospheric material that has small particle size and long atmospheric residence time is still more strongly influenced by volcano emissions than by industrial emissions. Throughout earth's history it is likely that volcano emissions were a major control on the environmental background levels of trace elements, in which plants and animals evolved their tolerances to these mostly-poisonous substances.
DE: 4801 Aerosols (0305)
DE: 4805 Biogeochemical cycles (1615)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting