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Black silica- and sulfate-bearing rock coatings in the Greater Sudbury area, Canada provide a record of atmospheric processes and emitted particulate matter associated with historical smelting operations in this area. Coating samples collected over the Greater Sudbury region are characterized with scanning electron microscopy, electron microprobe analysis, laser ablation inductively coupled mass-spectrometry, S-stable isotope measurements and micro X-ray fluorescence. On the micrometer scale, Cu, Pb, As, Se and S occur in close association within metal-sulfate rich layers composed of Fe- and Cu-sulfates. The concentrations of these and other elements do not represent their chemical proportions in the smelter plumes due to dissolution-precipitation processes, element substitutions and the stability of various phases involved in the coating formation. On the regional scale, the atomic ratios of Pb:Ni, As:Ni and Se:Ni decrease in the coatings with increasing distance from the smelting centers. This observation is consistent with higher wet deposition rates of small diameter Pb, As and Se-bearing primary sulfate aerosols (2.5mu m) Ni-bearing particulate matter. The mixing of primary (higher delta (super 34) S values) and secondary (lower delta (super 34) S values) sulfates explains the delta (super 34) S values of sulfates within the coatings close to smelting centers and the decrease in these values is attributed to the decrease in the ratio of primary to secondary sulfates with distance from the smelting centers. The information preserved in mineral surface-coatings together with an understanding of stoichiometry, geochemical processes and former environmental conditions provide a valuable record of atmospheric compositions, mixing, scavenging, deposition rates and oxidation processes, and the nature and source of anthropogenic releases to the atmosphere. Abstract Copyright (2012) Elsevier, B.V.

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GeoRef, Copyright 2018, American Geological Institute.<br/>2013-013335