| Titre | Geochemistry of southern Ontario Quaternary sediments |
| Télécharger | Téléchargement (publication entière) |
| |
| Licence | Veuillez noter que la Licence du gouvernement
ouvert - Canada remplace toutes les licences antérieures. |
| Auteur | Knight, R D ;
Bajc, A F; Kjarsgaard, B A; Crow, H; Stepner, D A J; Sharpe, D R; Russell, H A J |
| Source | Regional-Scale Groundwater Geoscience in Southern Ontario: An Ontario Geological Survey, Geological Survey of Canada, and Conservation Ontario Geoscientists Open House; par Russell, H A J; Ford, D; Holysh, S; Priebe, E H; Commission géologique du
Canada, Dossier public 8528, 2019 p. 18, https://doi.org/10.4095/313589  Accès ouvert |
| Année | 2019 |
| Séries alt. | Ontario Geological Survey, Open File Report 6349 |
| Éditeur | Ressources naturelles Canada |
| Réunion | Regional-Scale Groundwater Geoscience in Southern Ontario: Open House; Guelph; CA; février 27-28, 2019 |
| Document | dossier public |
| Lang. | anglais |
| DOI | https://doi.org/10.4095/313589 |
| Media | en ligne; numérique |
| Référence reliée | Cette publication est contenue dans Regional-Scale Groundwater Geoscience in Southern Ontario: An Ontario Geological Survey, Geological Survey of Canada, and Conservation Ontario Geoscientists Open House |
| Formats | pdf |
| Province | Ontario |
| SNRC | 30; 31B; 31C; 31D; 31E; 31G; 40; 41A; 41G; 41H/03; 41H/04; 41H/05; 41H/06; 41H/12; 41H/13 |
| Région | le sud de l'Ontario; Great Lakes |
| Lat/Long OENS | -84.0000 -74.0000 46.0000 41.5000 |
| Sujets | eau souterraine; aquifères; géochimie du sédiment; trous de mine; échantillons carrotés; méthodes de fluorescence aux rayons x; analyse par spectromètre de masse; origine; géologie du substratum rocheux;
lithologie; roches sédimentaires; carbonates; dolomites; calcaires; géochimie du calcium; géochimie du magnesium; dépôts glaciaires; tills; Till de Newmarket ; Till de Catfish Creek ; Santé humaine; hydrogéologie; géochimie; stratigraphie; Santé et
sécurité; Phanérozoïque; Cénozoïque; Quaternaire; Paléozoïque; Précambrien |
| Programme | Géoscience des eaux souterraines Caractéristiques d'aquifères et support cartographique |
| Diffusé | 2019 02 08 |
| Résumé | (disponible en anglais seulement)
Geochemical analysis constrained by stratigraphic units with detailed sampling of continuous core is rare in glaciated basins. The up to 200 m plus thickness of
surficial sediment cover across 74,000 km2 area of southern Ontario (S-ON) and the presence of many hundred continuously cored boreholes provided an opportunity to investigate the chemostratigraphy of a large glaciated basin. The S-ON basin setting
over Phanerozoic sedimentary carbonate and shale, and bounded by igneous and metamorphic rocks of Canadian Shield, provides an ideal setting for geochemical provenance studies and methods development. Geochemical analysis of 3,815 surficial sediment
samples from 53 boreholes have been analysed via portable X-ray fluorescence spectrometry (pXRF) and traditional laboratory geochemical analytical methods.
Comparison of geochemistry from ICP-ES/MS and with pXRF indicates good characterization of
the basin chemistry by the laboratory and pXRF analysis methods. Significant changes in elemental concentrations within individual cores are identified in multiple contexts, i) across formation contacts, ii) internally within formations, iii) absence
of change across formation boundaries. These likely represent changes in depositional processes and provenance between Precambrian Shield and Paleozoic sources. Changes in elemental concentrations are commonly not correlated between boreholes at
either the formation or sub formation level. On a regional scale, the geochemical ratio of CaO+MgO/SiO2+Al2O3 provides a Provenance Indicator (PI) to determine elemental contributions from a Paleozoic carbonate source relative to contributions from
Precambrian Shield sources. As calcium and magnesium occurs in markedly higher concentrations in Paleozoic carbonate rocks, a higher PI value reflects greater input of material derived from these Paleozoic sedimentary rocks. Examination of the
Newmarket Till using this PI shows a correlation between the amount of carbonate-derived material in the till-matrix and sampling distance relative to the shield margin indicates the deposition of increasingly carbonate-rich surficial sediments to a
maximum at approximately 80-100 km south of the Shield-margin. Additionally to the PI, a geochemical distinction is observed between sediments deposited east (carbonate dominated) and west (dolomite dominated) of the Niagara Escarpment. Elevated MgO
and CaO west of the Niagara Escarpment (Catfish Creek Till) indicates sourcing of Silurian dolomite, whereas east of the Escarpment (Newmarket Till) CaO-rich till is due to sourcing of Ordovician limestone.
The geochemical study of Quaternary
sediments in southern Ontario has not found any evidence of elemental concentrations that might adversely affect groundwater quality and human health. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Volume des résumés pour la Commission géologique de l'Ontario et la commission geologique du Canada géoscience des eaux souterraines de la CGC
portes ouvertes avec conservation Ontario. |
| GEOSCAN ID | 313589 |
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