| Titre | New insights on regional stratigraphy and hydrogeology based on surficial and subsurface sediment mapping in Simcoe County, southern Ontario |
| Télécharger | Téléchargement (publication entière) |
| |
| Licence | Veuillez noter que la Licence du gouvernement
ouvert - Canada remplace toutes les licences antérieures. |
| Auteur | Mulligan, R P M |
| Source | Regional-scale groundwater geoscience in southern Ontario: an Ontario Geological Survey, Geological Survey of Canada, and Conservation Ontario open house; par Russell, H A J ; Ford, D; Priebe, E H; Commission géologique du Canada, Dossier public 8212,
2017 p. 27, https://doi.org/10.4095/299784  Accès
ouvert |
| Année | 2017 |
| Éditeur | Ressources naturelles Canada |
| Réunion | Ontario Geological Survey and Geological Survey of Canada groundwater geoscience open house; Guelph; CA; mars 1-2, 2017 |
| Document | dossier public |
| Lang. | anglais |
| DOI | https://doi.org/10.4095/299784 |
| 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 open house |
| Formats | pdf |
| Province | Ontario |
| SNRC | 31D/05; 31D/11; 31D/12; 31D/13; 31D/14; 41A/07; 41A/08; 41A/09; 41A/10; 41A/16 |
| Région | Simcoe County; Lake Simcoe |
| Lat/Long OENS | -80.7500 -79.0000 45.0000 44.2500 |
| Sujets | eau souterraine; aquifères; ressources en eau souterraine; gestion des ressources; unités hydrostratigraphiques; régimes des eaux souterraines; écoulement de la nappe d'eau souterraine; dépôts glaciaires;
tills; dépôts glaciolacustres; sables; graviers; silts; argiles; trous de mine; analyses granulométriques; topographie; dépôts postglaciaires; érosion; Formation de Thorncliffe ; Till de Newmarket ; Approvisionnement en eau; hydrogéologie;
stratigraphie; géologie des dépôts meubles/géomorphologie; Phanérozoïque; Cénozoïque; Quaternaire |
| Programme | Géoscience des eaux souterraines , Aquifer Assessment & support to mapping |
| Diffusé | 2017 02 22 |
| Résumé | (disponible en anglais seulement)
The integration of detailed field mapping of surficial sediments and landforms with information obtained from 14 continuously-cored boreholes are providing key
insights into the character and distribution of major sediment packages that form regionally significant hydrostratigraphic units that control groundwater flow systems within Simcoe County.
Six major sediment packages are observed, forming
successions >160 m thick. A dense sandy till (LCT) overlies the bedrock at most locations in the study area. This till is locally overlain by glaciolacustrine deposits (LGL), which are generally fine-grained although sandy facies are encountered and
gravel deposits forming units up to 48 m thick have been observed in two boreholes to date. A fine-grained till (LFT) overlies the lower glaciolacustrine deposits forming a continuous, highly undulating marker bed in the subsurface. The upper surface
of the till shows evidence of subaerial weathering at higher elevations (> 170m asl). It is overlain by a fining-upward succession of predominantly sand with lesser gravel and local accumulations of silt and clay-rich diamictons (TF), tentatively
assigned to the Thorncliffe Formation. These deposits are overlain by a dense silty sand to sand till (NT) ranging from 2 to 30 m thick and correlative with the Newmarket Till. Particle size analysis of this till shows a progressive coarsening
northward. Significant topographic variation in the Newmarket Till is observed across the study area - its upper surface ranging from 150 to 310 m asl. This highly undulating unit imparts a strong control on the character of overlying deposits. Where
the till is found at lower elevations, laminated silts and clays form the bulk of the deglacial succession (LA). At higher elevations (>230 m asl), sands and gravels dominate.
The lower parts of the succession (LCT, LGL, LFT) do not commonly host
significant aquifers. However, the bedrock interface aquifers can meet the demands for rural domestic use, and where the thick gravel deposits are encountered, significant groundwater resources may be present, especially given its occurrence at
several tens of meters below modern Georgian Bay. Within the study area, the Thorncliffe Formation deposits form a regionally significant confined aquifer. It occurs regionally beneath both uplands and lowlands and, in many areas, artesian conditions
are present. The Newmarket Till forms a regionally significant leaky aquitard, but coarser textures observed in this till in the north appear to significantly decrease its competency as an aquitard. Deglacial sediments generally form thick aquitards
in low-lying areas but may form unconfined aquifers at higher elevations. Additionally, erosion of the Newmarket Till during deglaciation has led to preferential groundwater flow path that govern groundwater seepages and create large piping features.
Geophysical studies have been carried out to better constrain the architecture of major sediment packages in the subsurface and to characterize the physical properties of the major stratigraphic units. In-situ hydrogeologic tests are planned in order
to provide preliminary analysis of aquifer capacities and assess hydraulic connection of aquifers in the region. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Procès-verbaux pour la géoscience des eaux souterraines à échelle régionale Organisée par la Commission géologique de l'Ontario, la Commission
géologique du Canada et les géoscientifiques de Conservation Ontario. La journée portes ouvertes est prévue pour 2017-03-01 et 02. L'objectif est l'engagement du public et la diffusion de la géoscience dans le sud de l'Ontario au cours de la dernière
année. |
| GEOSCAN ID | 299784 |
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