|Titre||The significance of buried valleys to groundwater systems in the Oak Ridges Moraine region, Ontario: extent, architecture, sedimentary facies and origin of valley settings in the ORM region|
|Auteur||Sharpe, D R; Russell, H A J; Pugin, A|
|Source||Commission géologique du Canada, Dossier public 6980, 2013, 87 pages, https://doi.org/10.4095/292673 (Accès ouvert)|
|Éditeur||Ressources naturelles Canada|
|Media||en ligne; numérique|
|SNRC||30M/13; 30M/14; 31D/01; 31D/02; 31D/04; 31D/05; 31D/08; 31G/05; 40P/16|
|Lat/Long OENS||-80.5000 -75.5000 44.5000 43.7500|
|Sujets||ressources en eau souterraine; régimes des eaux souterraines; levés des eaux souterraines; vallées enfouies; aquifères; stratigraphie du till; lithostratigraphie; faciès sédimentaires; dépôts glaciaires;
topographie glaciaire; moraines; Moraine d'Oak Ridges ; Till d'Halton ; Till de Newmarket ; hydrogéologie; géologie des dépôts meubles/géomorphologie; Phanérozoïque; Cénozoïque; Quaternaire|
|Illustrations||location maps; digital elevation models; stratigraphic sections; graphs; block diagrams; cross-sections; photographs|
Bibliothèque de Ressources naturelles Canada - Ottawa (Sciences de la Terre)
|Programme||Aquifer Assessment & support to mapping, Géoscience des eaux
|Diffusé||2013 06 18|
|Résumé||(disponible en anglais seulement)|
The fieldtrip traverses the glaciated landscape of southeastern Ontario from the Niagara Escarpment to the Ottawa Valley. The focus of the trip is on the
glacial geology of a continental basin and tunnel valleys hosted within the glacial stratigraphy of the Oak Ridges Moraine region. Using digital elevation models, and detailed geological mapping, a system of anabraching valleys has been classified on
the basis of length, width and depth. The valleys have been traced beneath the Oak Ridges Moraine using high-quality shallow reflection seismic and continuous borehole data. The trip presents a suite of subsurface data with outcrop sedimentology in
support of meltwater process models and depositional environments. Process models are considered to relate to regional subglacial landscapes and are used to explain the origin of regional unconformities and the formation of tunnel valleys.
Depositional process models, such as the jet-efflux model, will be discussed to interpret key sedimentary facies and evidence for hydraulic jumps where rapid flow meets standing bodies of water.
The trip starts at the famous Scaborough Bluffs on
Lake Ontario, with a discussion of the regional glacial stratigraphy and units beneath the late glacial Newmarket Till, truncated by regional unconformities. Subsequent stops on day one highlight inter-valley sediments beneath the Oak Ridges Moraine
and outcrop sediments of the ORM interpreted within a subaqueous fan setting. Day two reviews the surface expression of tunnel valleys, seismic mapping of buried valleys and regional meltwater concepts for tunnel valley formation. It will also visit
an outstanding outcrop site that reveals depositional elements (jet- model and hydraulic jump processes) beyond the inferred tunnel channel depression. On day three, the trip traverses the length of the Oak Ridges Moraine and beyond, to view tunnel
valleys, sediments of the ORM, drumlin fields and eskers. The final day of the trip offers a hands-on inspection of continuous cores, highlighting the sedimentary facies, downhole geophysics and geochemistry of key basin stratigraphic units that
frame channel complexes.
The principal objective of the fieldtrip is to assess a 200 m thick glacial basin with tunnel valleys and fills with respect to its reservoir analogue potential for similar Paleozoic glaciogenic deposits. Such deposits
represent important hydrocarbon reservoirs in North Africa and the Middle East. The secondary trip objective is to demonstrate the field support for a range of methods and process-based sedimentary models for tunnel valley formation and deposition of
related channel-fill facies.