Shining light on black rock coatings in smelter-impacted areas

摘要: Earth scientists have long known of the existence black coatings on exposed rocks in smelter-impacted areas such as Sudbury, Ontario or Rouyn-Noranda, Quebec. Black rock Greater Sudbury area are remarkable geological records atmospheric conditions, including mixing, scavenging, and oxidation processes, deposition rates, nature source anthropogenic releases to atmosphere. The composed an amorphous silica matrix that has trapped atmosphere-borne nanoparticles preserved their chemical isotopic signature. These product high emissions SO2 subsequent non-stoichiometric dissolution siliceous rocks. contain spherical smelter-derived Cu–Ni-oxide particulate matter (micrometre nanometre-sized) metal-sulphate rich layers nanometer aggregates Fe–Cu sulphates. Lead, As, Se-bearing emitted from smelters incorporated metal-sulphate-rich along atmosphere-coating interface, presumably during coating formation. On a regional scale, ratios between different metal(loid)s indicate small diameter primary Pb, As sulphate aerosols been deposited at higher rates compared larger, Ni-bearing matter. High sulphur isotope values closer smelting centres decrease with distance is attributed increase mixing secondary SOMMAIRE Les geoscientifiques connaissent depuis longtemps l’existence d’une couche noire sur les roches exposees aux abords des fonderies comme celles de en ou Rouyn-Noranda au Quebec.   couches noires la grande region constituent remarquables enregistrements geologiques phenomenes atmospheriques, notamment processus melange, piegeage, et d'oxydation, ainsi que taux sedimentation l’origine rejets anthropiques dans l'atmosphere.   Ces sont constituees d'une matrice silice amorphe qui piege nanoparticules atmospheriques conserve leur signature chimique isotopique.  le produit fortes non-stœchiometrique subsequente siliceuses exposees.  contiennent spherules particules d’oxydes Cu-Ni (de taille micrometrique nanometrique) issues fonderie, riches sulfate metaux d’agregats nanometriques sulfates Fe-Cu.   plomb, d’As Se emises par incorporees metal l'interface l’atmosphere cette couche, probablement lors formation couche.  A l’echelle regionale, rapports concentration differents metalloides indiquent faible diametre primaires ont ete deposes plus eleves nickeliferes dimension.  valeurs elevees isotopes du soufre observees proximite diminution fonction l’eloignement attribuees une augmentation melange entre l’emission post-emission.