Despite increasing concern about the presence of heavy metals, pesticides and other toxins in indoor environments, very little is known about the physical and chemical composition of ordinary household dust. This study represents the first systematic investigation of the mineralogical composition of indoor dust in residential housing in Canada. Specimens of dust were obtained from homes in six geographically separate cities in the Province of Ontario: two located on the metamorphic and igneous rocks of the Precambrian Canadian Shield (Thunder Bay and Sudbury), the other four located on Palaeozoic limestone and shale dominated bedrock (Barrie, Burlington, Cambridge, and Hamilton). Forty samples of household vacuum dust were obtained. The coarse fraction (80 – 300 µm) of this dust was subjected to flotation (using water) to separate the organic components (e.g. insect fragments, dander), natural and synthetic materials (e.g. fibres, plastics) from the mineral residue. The mineral fraction was then analyzed using quantitative point counting, polarizing light microscopy, powder X-ray diffraction and scanning electron microscopy methods. Despite the great distances between the sampling localities and the distinct differences in bedrock geology, the mineral fraction of dust from all six cities is remarkably similar and dominated by quartz and feldspar, followed by lithic fragments, calcite, and amphibole. Some evidence of the influence of local geology can nevertheless be found. For example, a relatively higher proportion of sulphide minerals is observed in the two cities on the Canadian Shield where these minerals are clearly more abundant in the bedrock. Specimens from Sudbury, Canada’s largest mining centre located atop a nickel-sulphide mineral deposit, showed the highest sulphide contents. Quartz is the dominant mineral in all cities. All quartz grains have internal strain features and fluid inclusions that are indicative of a metamorphic-igneous provenance. In all cities, sand is used on the streets as an abrasive for traction during the icy winter season. This sand is obtained in all cases from local glaciofluvial deposits that were ultimately derived principally from the rocks of the Canadian Shield in the last Pleistocene glaciations that affected all of Ontario. Thus, tracking in sand is the most plausible mechanism by which quartz was introduced into these homes since sampling was done, in all cases, in the winter season. The results indicate that glacial deposits dominate the mineral composition of indoor dust in Ontario cities and that nature of the bedrock immediately underlying the sampling sites is relatively of minor importance.

Despite increasing concern about the presence of heavy metals, pesticides and other toxins in indoor environments, very little is known about the physical and chemical composition of ordinary household dust. This study represents the first systematic investigation of the mineralogical composition of indoor dust in residential housing in Canada. Specimens of dust were obtained from homes in six geographically separate cities in the Province of Ontario: two located on the metamorphic and igneous rocks of the Precambrian Canadian Shield (Thunder Bay and Sudbury), the other four located on Palaeozoic limestone and shale dominated bedrock (Barrie, Burlington, Cambridge, and Hamilton). Forty samples of household vacuum dust were obtained. The coarse fraction (80 – 300 µm) of this dust was subjected to flotation (using water) to separate the organic components (e.g. insect fragments, dander), natural and synthetic materials (e.g. fibres, plastics) from the mineral residue. The mineral fraction was then analyzed using quantitative point counting, polarizing light microscopy, powder X-ray diffraction and scanning electron microscopy methods. Despite the great distances between the sampling localities and the distinct differences in bedrock geology, the mineral fraction of dust from all six cities is remarkably similar and dominated by quartz and feldspar, followed by lithic fragments, calcite, and amphibole. Some evidence of the influence of local geology can nevertheless be found. For example, a relatively higher proportion of sulphide minerals is observed in the two cities on the Canadian Shield where these minerals are clearly more abundant in the bedrock. Specimens from Sudbury, Canada’s largest mining centre located atop a nickel-sulphide mineral deposit, showed the highest sulphide contents. Quartz is the dominant mineral in all cities. All quartz grains have internal strain features and fluid inclusions that are indicative of a metamorphic-igneous provenance. In all cities, sand is used on the streets as an abrasive for traction during the icy winter season. This sand is obtained in all cases from local glaciofluvial deposits that were ultimately derived principally from the rocks of the Canadian Shield in the last Pleistocene glaciations that affected all of Ontario. Thus, tracking in sand is the most plausible mechanism by which quartz was introduced into these homes since sampling was done, in all cases, in the winter season. The results indicate that glacial deposits dominate the mineral composition of indoor dust in Ontario cities and that nature of the bedrock immediately underlying the sampling sites is relatively of minor importance.

Despite increasing concern about the presence of heavy metals, pesticides and other toxins in indoor environments, very little is known about the physical and chemical composition of ordinary household dust. This study represents the first systematic investigation of the mineralogical composition of indoor dust in residential housing in Canada. Specimens of dust were obtained from homes in six geographically separate cities in the Province of Ontario: two located on the metamorphic and igneous rocks of the Precambrian Canadian Shield (Thunder Bay and Sudbury), the other four located on Palaeozoic limestone and shale dominated bedrock (Barrie, Burlington, Cambridge, and Hamilton). Forty samples of household vacuum dust were obtained. The coarse fraction (80 – 300 µm) of this dust was subjected to flotation (using water) to separate the organic components (e.g. insect fragments, dander), natural and synthetic materials (e.g. fibres, plastics) from the mineral residue. The mineral fraction was then analyzed using quantitative point counting, polarizing light microscopy, powder X-ray diffraction and scanning electron microscopy methods. Despite the great distances between the sampling localities and the distinct differences in bedrock geology, the mineral fraction of dust from all six cities is remarkably similar and dominated by quartz and feldspar, followed by lithic fragments, calcite, and amphibole. Some evidence of the influence of local geology can nevertheless be found. For example, a relatively higher proportion of sulphide minerals is observed in the two cities on the Canadian Shield where these minerals are clearly more abundant in the bedrock. Specimens from Sudbury, Canada’s largest mining centre located atop a nickel-sulphide mineral deposit, showed the highest sulphide contents. Quartz is the dominant mineral in all cities. All quartz grains have internal strain features and fluid inclusions that are indicative of a metamorphic-igneous provenance. In all cities, sand is used on the streets as an abrasive for traction during the icy winter season. This sand is obtained in all cases from local glaciofluvial deposits that were ultimately derived principally from the rocks of the Canadian Shield in the last Pleistocene glaciations that affected all of Ontario. Thus, tracking in sand is the most plausible mechanism by which quartz was introduced into these homes since sampling was done, in all cases, in the winter season. The results indicate that glacial deposits dominate the mineral composition of indoor dust in Ontario cities and that nature of the bedrock immediately underlying the sampling sites is relatively of minor importance.

Les peintures rupestres de l’Ontario font partie du grand ensemble de l'art rupestre du Bouclier Canadien. Ce terme recouvre une réalité géologique autant qu'ethnographique, puisque cette région est essentiellement habitée par les Algonquiens. La retraite des glaces laissa un paysage criblé de lacs et de cours d'eau dont les artistes amérindiens peignirent les roches riveraines. Les peintres élirent de préférence des rochers de granit ou de gneiss, lissés par les glaces et plongeant, le long des rivages, presque à la verticale dans l'eau. <p>Depuis une dizaine d'années, les recherches en art rupestre se développent de plus en plus :de nouvelles techniques, ainsi que des interprétations récentes, prenant plus en compte les autres domaines scientifiques font leur apparition. Toutes ces approches sont largement diffusées par des colloques, des congrès et des périodiques spécialisés. Néanmoins, elles sont encore peu appliquées dans de nombreuses régions, les représentations ne faisant généralement l'objet que d'un relevé succinct, d'une identification des principaux motifs et d'une chronologie relative incertaine. Dans les années '60, Leroi-Gourhan rejetait, à juste titre pour l'art pariétal européen, le comparatisme ethnologique et il préconisait de "recevoir directement du Paléolithique ce qu'il apportait spontanément". Les spécialistes européens se focalisèrent alors sur les peintures et gravures et les étudièrent de la même manière que n'importe quel artefact archéologique (typologie, chronologie, carte de répartitions, analyse quantitative…). Au contraire, en Amérique et en Australie, où l'approche ethnographique et ethnologique est possible, les chercheurs se concentrèrent principalement sur ce dernier axe de recherche. Les dernières recherches en Europe de l'art pariétal paléolithique ont démontré l'importance d'une approche à la fois plus objective, plus exhaustive et plus contextuelle, approche qui fait encore malheureusement très largement défaut dans les travaux consacrés aux art rupestres, notamment les peintures rupestres du Bouclier canadien. Or, ces manifestations "esthétiques" sont susceptibles de nous livrer des informations non seulement sur le fonctionnement mental et spirituel des hommes qui les ont réalisées, par l'analyse des contenus graphiques mais aussi sur leur fonctionnement social grâce à la reconstitution des diverses chaînes opératoires mises en œuvre pour leur obtention. Il est donc désormais indispensable de lier les deux approches et de traiter ces documents archéologiques, tant d’un point de vue anthropologique qu’archéologique. C’est-à-dire, en analysant les peintures dans leur contexte (importance du rocher et des fissures, position du rocher sur le lac et importance de la voie de communication) et en les reliant à ce que nous connaissons de la mythologie et des pratiques culturelles des sociétés amérindiennes. <p><p> / Doctorat en philosophie et lettres, Orientation histoire de l'art et archéologie / info:eu-repo/semantics/nonPublished

Despite increasing concern about the presence of heavy metals, pesticides and other toxins in indoor environments, very little is known about the physical and chemical composition of ordinary household dust. This study represents the first systematic investigation of the mineralogical composition of indoor dust in residential housing in Canada. Specimens of dust were obtained from homes in six geographically separate cities in the Province of Ontario: two located on the metamorphic and igneous rocks of the Precambrian Canadian Shield (Thunder Bay and Sudbury), the other four located on Palaeozoic limestone and shale dominated bedrock (Barrie, Burlington, Cambridge, and Hamilton). Forty samples of household vacuum dust were obtained. The coarse fraction (80 – 300 µm) of this dust was subjected to flotation (using water) to separate the organic components (e.g. insect fragments, dander), natural and synthetic materials (e.g. fibres, plastics) from the mineral residue. The mineral fraction was then analyzed using quantitative point counting, polarizing light microscopy, powder X-ray diffraction and scanning electron microscopy methods. Despite the great distances between the sampling localities and the distinct differences in bedrock geology, the mineral fraction of dust from all six cities is remarkably similar and dominated by quartz and feldspar, followed by lithic fragments, calcite, and amphibole. Some evidence of the influence of local geology can nevertheless be found. For example, a relatively higher proportion of sulphide minerals is observed in the two cities on the Canadian Shield where these minerals are clearly more abundant in the bedrock. Specimens from Sudbury, Canada’s largest mining centre located atop a nickel-sulphide mineral deposit, showed the highest sulphide contents. Quartz is the dominant mineral in all cities. All quartz grains have internal strain features and fluid inclusions that are indicative of a metamorphic-igneous provenance. In all cities, sand is used on the streets as an abrasive for traction during the icy winter season. This sand is obtained in all cases from local glaciofluvial deposits that were ultimately derived principally from the rocks of the Canadian Shield in the last Pleistocene glaciations that affected all of Ontario. Thus, tracking in sand is the most plausible mechanism by which quartz was introduced into these homes since sampling was done, in all cases, in the winter season. The results indicate that glacial deposits dominate the mineral composition of indoor dust in Ontario cities and that nature of the bedrock immediately underlying the sampling sites is relatively of minor importance.