| Titre | Geological and hydrogeological models of the 'Yonge Street' aquifer, south-central Ontario |
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| Auteur | Gerber, R; Hoylsh, S; Russell, H A J ; Sharpe, D R |
| Source | Conference program and abstracts, IAH-CNC 2015 Waterloo; 2015 p. 65-66 |
| Image |  |
| Année | 2015 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20150064 |
| Éditeur | IAH |
| Réunion | IAH-CNC 2015 Waterloo; Waterloo, ON; CA; Octobre 27-30, 2015 |
| Document | livre |
| Lang. | anglais |
| Media | papier; numérique |
| Formats | pdf |
| Province | Ontario |
| SNRC | 40P/08; 40P/09 |
| Région | Brantford; Cambridge; Guelph |
| Lat/Long OENS | -80.5000 -80.0000 43.7500 43.2500 |
| Sujets | dépôts glaciaires; moraines; aquifères; eau souterraine; lithologie; sables; argiles; silts; graviers; modèles sédimentaires; milieu sédimentaire; analyses stratigraphiques; corrélations stratigraphiques;
puits; carottes; trous de mine; établissement de modèles; Moraine de Paris ; Moraine de Galt ; hydrogéologie; géologie des dépôts meubles/géomorphologie; stratigraphie; sédimentologie; Nature et environnement; Sciences et technologie; Phanérozoïque;
Cénozoïque; Quaternaire |
| Programme | Géoscience des eaux souterraines , Aquifer Assessment & support to mapping |
| Diffusé | 2015 10 14 |
| Résumé | (disponible en anglais seulement)
In the Aurora, Newmarket and Queensville areas of the Greater Toronto Area, south-central Ontario, municipal water supply is obtained from the 'Yonge Street
aquifer' (YSA), an informal name long used to describe relatively deep sand and gravel deposits. These deposits were previously described as discontinuous, perhaps channelized and possibly associated with buried bedrock valleys, largely interpreted
from data at a few municipal well fields. Despite much historical and recent geological and hydrogeological work, including numerical groundwater flow modelling, the fundamental geological and hydrogeological framework (i.e. conceptual model) for the
YSA has not been clearly developed and documented.
Based on high-quality geophysical and geological data (seismic profiles, continuously-cored, sedimentologically-logged boreholes, downhole geophysics, geological mapping and 3-D modeling) revised
conceptual geological and hydrogeological models of the area are presented. The data reveal a sedimentary succession (e.g., ~140 m thickness at Aurora) that is truncated by a number of erosional unconformities characterized by deeply incised
channels, locally extending to bedrock, with a ~NS to NE-SW orientation, both beneath and above the regional Newmarket Till stratigraphic marker. Channels may occur stratigraphically stacked and nested with Newmarket Till locally filling depressions.
Core and seismic data permit identification of channelized Thorncliffe Fm. eroded into older sand and mud Scarborough Fm. equivalents. The Thorncliffe Fm. consists of fining upward transitions from coarse gravel, to sand, to rhythmically bedded mud
interpreted to be deposited within a channel-esker-subaqueous fan complex. The YSA aquifer is one component of a system of similar deposits recognized across the region beneath drumlinized Newmarket Till.
The accompanying hydrogeological model
benefits from a strong conceptual understanding of vertical and lateral facies changes (and connection to older aquifers) in the Thorncliffe Fm. depositional model. The subaqueous fan gravel-sand-mud, fining-upward facies succession provides a
capping aquitard to YSA, in addition to the overlying Newmarket Till aquitard. Lateral coarse to fine facies transitions are very rapid perpendicular to paleoflow and explain relatively low-yield wells drilled near YSA municipal wells. Facies
transitions are much longer along paleoflow, as supported by pumping tests in a similar aquifer system north of Markham which have high-yield hydraulic connections of ~1-10 kms.
The conceptual models documented in this paper are critical to
guiding groundwater exploration and management. Paramount to improved knowledge is collection of high-quality subsurface data (including hydraulic data) that aids in developing a geological framework that represents the sedimentary system of the
basin and its internal flow system. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Documente les sédimentologie et le contexte hydrostratigraphique de la aquifer de rue Yonge. Sur la base de ce cadre données hydrauliques est
évaluée à fournir une caractérisation de l'aquifère. |
| GEOSCAN ID | 296501 |
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