Geological framework of the Laurentian trough aquifer system, southern Ontario

Sharpe, D R; Pugin, A J M; Russell, H A J

doi:10.1139/cjes-2017-0113

Cited by 14 publications

(46 citation statements)

References 123 publications

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“…The tunnel valleys that occur throughout the PDF and beneath the ORM (previously interpreted as tunnel channels; Brennand & Shaw ; Sharpe et al . , ) provided preferential pathways for meltwater and sediment transport from subglacial to submarginal and proglacial areas in the ORM (Brennand & Shaw ; Russell et al . ; Mulligan et al .…”

Section: Discussionmentioning

confidence: 99%

“…This ‘glacial’ theory was later challenged by workers who linked broad tracts of erosional terrain to drumlin and tunnel channel formation in the region, and related them to catastrophic releases of subglacial meltwater (Shaw & Gilbert ; Brennand & Shaw ; Sharpe et al . , ; Sharpe & Russell ). More recent studies have highlighted the importance of ice streams as geomorphic agents within southern Ontario and their ability to create extensive tracts of erosive and streamlined terrain (Ross et al .…”

Section: Summary Of Landform Characteristics Recently Mapped In Southmentioning

confidence: 99%

“…, ) or deflection of flowlines during discrete, successive flood events from different directions (Shaw & Gilbert ; Sharpe et al . ).…”

Section: Introductionmentioning

confidence: 97%

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Subglacial and ice‐marginal landforms in south‐central Ontario: implications for ice‐sheet reconfiguration during deglaciation

Mulligan

Eyles

Marich

2019

Boreas

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Regional‐scale, high‐resolution terrain data permit the study of landforms across south‐central Ontario, where the bed of the former Laurentide Ice Sheet is well exposed and passes downflow from irregular topography on Precambrian Shield highlands to flat‐lying Palaeozoic carbonate bedrock, and thick (50 to >200 m) unconsolidated sediment substrates. Rock drumlins and megagrooves are eroded into bedrock and mega‐scale glacial lineations (MSGL) occur on patchy streamlined till residuals in the Algonquin Highlands. Downflow, MSGL pass into juxtaposed rock and drift drumlins on Palaeozoic bedrock and predominantly till‐cored drumlins in areas of thick drift. The Lake Simcoe Moraines, now traceable for more than 80 km across the Peterborough drumlin field (PDF), form a distinct morphological boundary: downflow of the moraine system, drumlins are larger, broader and show no indication of subsequent reworking by the ice, whereas upflow of the moraines, a higher degree of complexity in bedform pattern and morphology is distinguished. Discrete radial and/or cross‐cutting flowset terminate at subtle till‐cored moraine ridges downflow of local topographic lows, indicating multiple phases of late‐stage ice flow with strong local topographic steering. More regional‐scale flow switching is evident as NW‐orientated bedforms modify drumlins south of the Oak Ridges Moraine, and radial flowset emanate from areas within the St. Lawrence and Ottawa River valleys. Most of the drumlins in the PDF formed during an early, regional drumlinization phase of NE–SW flow that followed the deposition of a thick regional till sheet. These were subsequently modified by local‐scale, topographically controlled flows that terminate at till‐cored moraines, providing evidence that the superimposed bedforms record dynamic ice (re)advances throughout the deglaciation of south‐central Ontario. The patterns and relationships of glacial landform distribution and characteristics in south‐central Ontario hold significance for many modern and palaeo‐ice sheets, where similar downflow changes in bed topography and substrate lithology are observed.

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Section: Discussionmentioning

confidence: 99%

Section: Summary Of Landform Characteristics Recently Mapped In Southmentioning

confidence: 99%

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Subglacial and ice‐marginal landforms in south‐central Ontario: implications for ice‐sheet reconfiguration during deglaciation

Mulligan

Eyles

Marich

2019

Boreas

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“…A third major bedrock valley type, the escarpment trough setting, is presented in a regional study of the Laurentian trough by Sharpe et al (2018). This work brings together a wealth of previously published and new continuous-core, geological and geophysical (seismic) data to examine an extensive, complex buried valley fill.…”

Section: Buried Valleysmentioning

confidence: 99%

“…A robust geological framework used in conjunction with in situ hydraulic data can then enable prediction of hydraulic conditions in areas with sparse data (e.g., Fogg 1986; Anderson 1989). Since the early 1990s, and particularly since the Walkerton Inquiry (2002), extensive datasets have been collected on both surface and subsurface Quaternary deposits of southern Ontario (e.g., Bajc et al 2018;Burt 2018;Sharpe et al 2018). Much of this information has been published in government data releases, conference abstracts, graduate student theses, and technical reports.…”

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confidence: 99%

Quaternary geology of southern Ontario and applications to hydrogeology

et al. 2018

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Quaternary geology of southern Ontario and applications to hydrogeology IntroductionThe southern Ontario (lowland) region is a sedimentary basin covering ϳ72 000 km 2 located within the Great Lakes watershed (e.g., Sharpe et al. 2014a). It is bounded by Canadian Shield to the north and east, and three Great Lakes to the south and west (Ontario, Erie, and Huron). The region is the economic heartland of Canada accounting for over 40% of the Canadian Gross Domestic Product. It contains one-third of the Canadian population and has the highest population density in the country. The Great Lakes cumulatively account for approximately 84% of North Americas available freshwater and form the largest potential transboundary groundwater -surface-water resource between the USA and Canada (Environment Canada and the U.S. Environmental Protection Agency 2014). Ironically, there is significant reliance on groundwater for potable, commercial, and agricultural water uses. Approximately 3 million people use groundwater in Ontario, with the majority of these located in southern Ontario. Extraction by domestic systems support ϳ1.3 million people and ϳ1.9 million people use municipal supplies (e.g., Waterloo, Guelph; Sharpe et al. 2014b).For a decade, from 2004 to 2015, groundwater studies in Ontario were dominated by the Source Protection Program that the provincial ministries of Environment and Climate Change, and Natural Resources and Forestry funded via Conservations Authorities in 22 Source Protection areas. The focus of this work was largely water budget modeling, the identification of threats to drinking water supplies, and the establishment of wellhead protection areas around municipal wells. This program was complemented by the Ontario Geological Survey's groundwater initiative, which focused on the collection and interpretation of new, high quality subsurface geoscience information to support regional groundwater understanding (Bajc et al. 2016). This research was a direct outcome of the recommendations of the Walkerton Inquiry (O'Connor 2002) that followed on the tragic events in a southwestern Ontario community where the water supply was compromised by poor wellhead design and lax water treatment checks and protocols, following a heavy rain event in the spring of 2000. Over 2000 people became ill, 7 people died, and the conservative, tangible cost to the provincial economy, up to 2002, was over $60 million (Livernois 2002).The O'Connor Report (2002) recognized the early leadership in Ontario of the Ontario Geological Survey and Geological Survey of Canada in providing the understanding on geologic controls to support knowledge of groundwater and surface-water relationships. Importantly, geological conceptualization is often the first step of any hydrogeological study as it provides important information about geometry and connectivity of units that may support withdrawal of large amounts of water, and the distribution and integrity of units that may act as a barrier to flow and contaminants. A robust geological framework ...

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The Ontario Line, another milestone in developing Toronto's public transit system

Neugebauer¹,

Chesser²,

Meyer³

et al. 2023

Geomechanics and Tunnelling

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The new Ontario Line is one of four priority transit projects announced by the province of Ontario in 2019 for the Greater Toronto Area (GTA). It will be a 15.6 km stand‐alone rapid transit line that will run through the city from Exhibition/Ontario Place in the southwest, through the heart of downtown Toronto, all the way to the Ontario Science Centre in the northeast. Over half of the route (9 km) is planned to run underground through new tunnels, with the remainder running along elevated and at‐grade rail corridor sections of track. Fifteen new stations are proposed, whereby eight are planned as deep underground structures. Most of these underground stations will be built in the downtown core, with numerous connections to the broader transit network of the GTA, including GO Transit rail services, the Toronto Transit Commission's (TTC) existing subway Lines 1 and 2, the Line 5 (Eglinton Crosstown LRT) currently under construction, as well as numerous bus and streetcar routes. The expected project benefits of Ontario Line are as follows: A faster and more reliable access to rapid transit system with more than 227,500 people living within walking distance to the new line. Reduction in crowding of existing Line 1 subway. Up to 47,000 jobs accessible by transit in 45 min or less for Toronto residents. Economic and community growth along the future transit line and significant reduction in traffic congestion and greenhouse gases by providing alternative transportation options. The Ontario Line is currently being delivered through a number of contracts with different procurement approaches.

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Geological framework of the Laurentian trough aquifer system, southern Ontario

Cited by 14 publications

References 123 publications

Subglacial and ice‐marginal landforms in south‐central Ontario: implications for ice‐sheet reconfiguration during deglaciation

Subglacial and ice‐marginal landforms in south‐central Ontario: implications for ice‐sheet reconfiguration during deglaciation

Quaternary geology of southern Ontario and applications to hydrogeology

The Ontario Line, another milestone in developing Toronto's public transit system

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