Mark S. Germani

Inter‐hemispheric Transport of Volcanic Ash from a 1259 A.D. Volcanic Eruption to the Greenland and Antarctic Ice Sheets

A strong volcanic sulfuric acid signal corresponding to an age of 1259 A.D. has been reported in ice cores from Greenland, Antarctica, and Arctic Canada. Tiny (< 5 μm) volcanic glass shards were reported previously in samples from this layer in an ice core from the South Pole. Here we report the discovery of volcanic glass shards from a contemporaneous layer in an ice core from Summit, Greenland. The major element composition of the glass shards in the Greenland sample are identical to those from the South Pole, confirming the assumption that has been made previously that the sulfuric acid signal in the ice cores is an inter-hemispheric time stratigraphic marker. The composition of these glass shards is similar to those produced by a 550–700 yrs. B.P. eruption of El Chichon volcano in Mexico, suggesting that it may be the source of the widely dispersed material.

Vapor-phase concentrations of arsenic, selenium, bromine, iodine, and mercury in the stack of a coal-fired power plant

A sampling and analysis procedure is described for determining vapor-phase concentrations of As, Se, Br, I, and Hg in the stack of a coal-fired power plant. The percentages of the total in-stack concentrations for these elements present in the vapor phase are as follows: Br, 98%; Hg, 98%; Se, 59%; As, 0.7-52%; and I, greater than or equal to99%. A lower limit of 99% was obtained for Cl. The vapor-phase concentration of As appears to be dependent upon the in-stack or filter mass loading. This indicates that a vaporization-condensation mechanism may control the vapor-phase concentrations of As. The result for Se indicate that the efficiency of the electrostatic precipitator affects particle vapor-phase fractionation. The results obtained in this study are compared with previous mass balance calculations.

Assessment of the record of the 1982 El Chichón eruption as preserved in Greenland snow

Variability in the SO42− and Cl− time series for the 1980s from 12 shallow snow pits across the Greenland ice sheet is used to evaluate the record of the 1982 El Chichon eruption and the potential for recording a moderate northern equatorial eruption in a single Greenland ice core. Composition of volcanic glass found in spring 1983 snow in one of the pits in the Summit region matches that from El Chichon glass, thereby verifying the deposition of material from the eruption. High Na+ and Cl− concentrations in this same layer probably represent deposition of the reaction products of halite and H2SO4 as observed in the stratosphere following the eruption. These findings and the presence of a Cl− signal in five of the other pits indicate that the Cl− aerosol component of some eruptions has the potential to remain aloft for at least 1 year after the eruption. Some of these aerosols may be adsorbed onto tephra particles. Distinct SO42− peaks that can be confidently linked to El Chichon were found in only 50% of the records developed through subseasonal sampling. However, in several other pits an elevated baseline, thought to represent more lengthy periods of El Chichon aerosol deposition as opposed to deposition from a single snowfall event, were observed. Smoothing of the original data by the calculation of annual SO42− flux resulted in the presence of high flux values between 1982 and 1984 (years thought to be affected by El Chichon aerosol deposition) in 9 of the 12 pits. These results suggest that a single ice core from anywhere in Greenland may record a signal from a northern equatorial eruption of magnitude similar to that of El Chichon about 75% of the time; this is despite the overall high levels of SO2−4 deposition from anthropogenic sources that now make identification and quantification of the volcanic SO2− portion of the record more difficult than obtaining the same data for preindustrial volcanism. Nevertheless, composite records from all the pits sampled yielded stratospheric loading (∼20 Mt) and optical depth (τ=0.13) estimates similar to stratospheric and satellite-based measurements following the eruption. Equally high SO42− concentration and flux values in snow from 1980 to 1982 reflect deposition from the series of middle to high northern latitude volcanic eruptions 1979–1981.

Fractionation of elements during copper smelting

A recent study of the elemental composition of particulate material collected from the plumes of five copper smelters in southeastern Arizona indicated that arsenic, lead, selenium, cadmium, zinc, tungsten, indium, and other chalcophilic elements are highly enriched in the plume materials relative to the background aerosol. Enrichments are due to the volatilization of these elements during copper smelting. Significant differences in the elemental compositions of plumes from the various smelters appear to be due to differences in the feed material, smelting conditions, and equipment use by the smelters. (3 graphs, 13 references, 7 tables)

Chemistry of individual aerosol particles from Chandler, Arizona, an arid urban environment

Atmospheric aerosol particles, collected at a site in Chandler, AZ, over a 12-day period in February and March 1982, were chemically analyzed with an automated scanning electron microscope. The fine-particle fraction, with minimum average diameters of 0.4 ..mu..m and effective maximum diameters of about 2 ..mu..m, contains numerous types of Pb-, Cu-, Zn-, P-, and S-bearing particles, most of probable anthropogenic origin. The concentrations of selected particle types, each with distinct elemental associations, have been tracked over the sampling period, thereby providing information about particle emission and transport. The concentrations of particle types containing one or more metals and S were strongly dependent upon prevailing wind direction; the predominant source was copper smelters located to the southeast of Phoenix. Other particle types probably had local sources, some of which were intermittent. The identification and tracking of chemically distinct types of individual particles are demonstrated to be powerful tools for understanding complex atmospheric aerosol systems.

A 100‐year record of North Pacific volcanism in an ice core from Eclipse Icefield, Yukon Territory, Canada

Iceland, and the 1989 Redoubt, Alaska, eruptions. Non-sea-salt SO4 2 residuals above a robust spline and empirical orthogonal function (EOF) analysis were used to identify volcanic SO4 2 signatures. Volcanic sulfate values are more conservatively identified by the EOF analysis as sulfate deposition from other sources is more robustly accounted for. Some eruptions are also recorded as peaks in non-sea-salt chloride. The volcanic signals in the Eclipse ice core are mostly attributable to Alaskan, Aleutian, or Kamchatkan eruptions. Conversely, the Eclipse ice core provides a poor record of globally significant tropical eruptions. These results are promising for the development of longer ice core based records of paleovolcanism in the North Pacific rim. INDEX TERMS: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0370 Atmospheric Composition and Structure: Volcanic effects (8409); 8409 Volcanology: Atmospheric effects (0370); KEYWORDS: Yukon Territory, ice cores, volcanism, atmospheric effects, Kamchatka, Alaska