|Titre||3-dimensional mapping of Quaternary deposits in the southern part of the County of Simcoe, Southern Ontario|
|Télécharger||Téléchargement (publication entière) |
|Auteur||Bajc, A F; Mulligan, R P M; Rainsford, D R B; Pugin, A J -M; Knight, R D; Crow, H L|
|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;
Priebe, E H; Holysh, S; Commission géologique du Canada, Dossier public 8363, 2018 p. 1, https://doi.org/10.4095/306484 (Accès ouvert)|
|Éditeur||Ressources naturelles Canada|
|Réunion||Regional-Scale Groundwater Geoscience in Southern Ontario: Open House; Guelph; CA; février 28 - mars 1, 2018|
|Media||en ligne; numérique|
|Référence reliée||Cette publication est contenue dans Russell, H A
J; Ford, D; Priebe, E H; Holysh, S; (2018). Regional-scale groundwater geoscience in southern Ontario: an Ontario Geological Survey, Geological Survey of Canada, and Conservation Ontario geoscientists open house, Commission géologique du Canada,
Dossier public 8363|
|SNRC||31D/05; 31D/11; 31D/12; 31D/13; 31D/14; 41A/07; 41A/08; 41A/09; 41A/10; 41A/16|
|Lat/Long OENS|| -80.7500 -79.0000 45.0000 44.2500|
|Sujets||techniques de cartographie; établissement de modèles; ressources en eau souterraine; gestion des ressources; utilisation du terrain; eaux de surface; épaisseur de la couverture meuble; topographie du
substratum rocheux; chronostratigraphie; dépôts postglaciaires; dépôts glaciaires; moraines; tills; Wisconsinien; Sangamonien; Illinoien; milieu sédimentaire; antecedents glaciaires; glaciation; déglaciation; Till de Newmarket ; Moraine d'Oak Ridges
; Élaboration des politiques; géologie des dépôts meubles/géomorphologie; hydrogéologie; géologie de l'environnement; sédimentologie; géophysique; géochimie; stratigraphie; Phanérozoïque; Cénozoïque; Quaternaire|
Bibliothèque de Ressources naturelles Canada - Ottawa (Sciences de la Terre)
|Programme||Aquifer Assessment & support to mapping, Géoscience des eaux souterraines|
|Diffusé||2018 02 16|
|Résumé||(disponible en anglais seulement)|
A 3-dimensional (3-D) mapping investigation of Quaternary deposits in the southern part of the County of Simcoe is one of several 3-D mapping projects currently
being undertaken as part of the Ontario Geological Survey's groundwater initiative within the Greater Golden Horseshoe area of southern Ontario. Following completion of these projects, a significant proportion of the most densely populated and
fastest growing region of the country will be modelled in 3-dimensions, laying the foundation for regional syntheses of subsurface geology.
The objective of this project is to develop an interactive 3-D model of Quaternary geology that can: 1)
aid in studies involving groundwater extraction, protection and remediation; 2) assist with the development of policies surrounding land use and nutrient management; and 3) help to further understand the interaction between surface and ground waters.
A better understanding of the geometry and inherent properties of the Quaternary sediments that overlie bedrock will assist with the development of revised source water protection plans and with the development of a geoscience-based management plan
for the groundwater resource.
Geoscience data collection was initiated in 2010 and consisted of detailed Quaternary mapping and sedimentological studies of the shallow subsurface, continuous coring to bedrock at 25 locations and a variety of
geophysical surveys including: ground gravity, airborne time-domain electromagnetics, downhole geophysical logging and seismic reflection. Supplementary grain size, carbonate, heavy mineral and geochemical analyses enabled an improved interpretation
of the subsurface stratigraphy.
The information gained from this work resulted in a refined understanding of drift thickness and bedrock topography for the Laurentian trough area as well as the identification of 6 regionally significant
chronostratigraphic units further subdivided into 15 layers. The main elements of the model, from youngest to oldest, include: 1) postglacial valley-fill deposits; 2) Oak Ridges Moraine (ORM) and equivalent deposits; 3) Newmarket Till; 4)
Scarborough-Thorncliffe Formation equivalents; 5) non-glacial (Sangamon- Middle Wisconsin) deposits and 6) Illinoian and possibly older glacial deposits. Advancements in the understanding of the regional-scale architecture, contact relationships and
depositional settings of these elements has allowed for an improved knowledge of the Quaternary history of the region. Notable observations include the identification of a widespread, non-glacial unit in the deep subsurface that likely spans the
Sangamon to Middle Wisconsin time interval and the recognition of significant topographic relief of the Newmarket Till, extending from drumlinized uplands into broad valleys previously interpreted as tunnel valleys produced by the catastrophic
release of subglacial meltwater. A protracted evolution for these valleys is currently being proposed. The character of groundwater flow within valley settings is more complex than observed in valleys underlying the ORM to the south. In Southern
Simcoe County, the valleys are largely infilled with fine-grained units and upward hydraulic gradients commonly inhibit interaction of shallow with deep groundwater flow systems.