The results of studies of dielectric-barrier discharge (DBD) plasma optical characteristics in mi... more The results of studies of dielectric-barrier discharge (DBD) plasma optical characteristics in mixtures of mercury diiodide vapor, xenon and helium are presented. Regularities in spectral, temporal and energy characteristics of plasma, depending on the partial pressures of the mixture components are established. An average and pulsed radiation power of 0.8 Watts and 293 Watts is reached respectively from the emission volume 111ˑ10-6 m 3 in violet-blue spectral range.
The hypothesis that Oak Ridges Moraine (ORM) formed between converging ice streams requires criti... more The hypothesis that Oak Ridges Moraine (ORM) formed between converging ice streams requires critical testing. Available data (e.g., DEMs, maps, seismic profiles, continuous cores, and pit exposures) are inconsistent with the converging ice stream hypothesis. Combined analysis of landform and subsurface data permits testing the ORM area stratigraphic sequence and sedimentary origin. Stratigraphic data indicate that drumlinized Newmarket Till, incised by N-S-oriented (tunnel) valleys, extends beneath ORM. Thus, streamlining on Newmarket Till is older than ORM and has no direct bearing on its formation. The N-S-trending valleys truncate streamlined Newmarket Till, extend to bedrock, have inset eskers, and occur beneath ORM. Hence, these valleys are older than ORM and have a subglacial rather than a proglacial origin. Overlying the mega-scale lineations (MSLs) and incised channels are topographically elevated (> 300 m asl), ORM glaciofluvial – glaciolacustrine sequences. Its east to ...
Information from a wide range of sources is integrated in a basin analysis of the Wabigoon Basin,... more Information from a wide range of sources is integrated in a basin analysis of the Wabigoon Basin, a Quaternary clay basin located on the Canadian Shield in northwestern Ontario. The basin sediments were deposited between 10.9 ka and 9.5 ka, along the margin of the Rainy Lobe of the Laurentide Ice Sheet, which formed the northern boundary of proglacial Lake Agassiz. The basin architecture is dominated by four major elements: end moraines, eskers, kames and a clay plain, all of which overlie irregular bedrock topography. End moraines, eskers and kames are composed mainly of a fining upward sequence of gravels and sands. The geometry of these sedimentary units, and their sedimentary structures indicates they were deposited mainly by high and low-density turbidity currents, on ice-marginal subaqueous outwash fans. Eskers contain a core of coarse gravel and sand deposited within subglacial meltwater conduits, overlain by subaqueous fan sediments deposited at the conduit mouth. Esker ridg...
In regions formerly covered by continental ice, till sheets may contain distinctive clastic parti... more In regions formerly covered by continental ice, till sheets may contain distinctive clastic particles derived from local bedrock sources such as ore bodies. Such particles, especially in thicker tills, may be distributed in three-dimensional dispersal trains or plumes. Developments in our understanding of glacial erosion, entrainment, and deposition over the past two or three decades help clarify formation of these plumes. Much of the debris in the basal ice of ice sheets is likely incorporated at places where water is freezing onto the base of the ice sheet. This water, largely a product of melting of basal ice further upglacier, has migrated downglacier under the influence of a gradient in the hydraulic potential controlled primarily by the ice surface slope and secondarily by basal topography and thermal regime. Refreezing occurs over a substantial distance along flow, so as the ice moves away from an ore body, material eroded from the body is later elevated above the bed by refr...
Canadian Water Resources Journal / Revue canadienne des ressources hydriques, 2014
ABSTRACT Aquifers of the Waterloo Moraine play a key role as the main source of drinking water fo... more ABSTRACT Aquifers of the Waterloo Moraine play a key role as the main source of drinking water for the Region of Waterloo. For the effective management of this water source, a sound understanding of the aquifers contained within and below the Moraine is essential. Critical knowledge required for this understanding includes the definition of the sediment facies distribution, architectural elements and geological origin of the Quaternary-aged deposits. A basin analysis approach has been applied to geologic data collection and interpretation to unravel the paleogeographic history of the study area and to provide a predictive framework for understanding its geological variability. Coarse (sand and gravel) sediment within the Waterloo Moraine was deposited during a series of high-energy meltwater discharge events from several sediment input corridors (eskers), into a deep, large, ice-supported glacial lake. This depositional setting led to a complex three-dimensional architecture comprising sand-gravel and mud units that are increasingly interbedded away from the multi-directional influx sources around the perimeter of the Moraine. A recently completed digital, three-dimensional geologic model of the area provides details of the various geological units that help refine the understanding of the hydrostratigraphy. This information has improved the understanding of groundwater flow (including interaction between surface and groundwaters) and has provided valuable information critical for source water protection. Information on the distribution, thickness, geometry and properties of these units has resulted in a better understanding of the potential linkages between near-surface recharge areas and deep aquifers across the region. This geological information is important in developing predictive models, for example, determining the location of high transmissivity zones within the moraine. Derivative products such as aquifer vulnerability and recharge maps may help inform policy makers in developing land use and nutrient management plans in the vicinity of well fields and sensitive lands.
Airborne electromagnetic and high resolution seismic geophysical data provide insight into comple... more Airborne electromagnetic and high resolution seismic geophysical data provide insight into complex buried valley geometry and internal sedimentary architecture of buried valleys in the Canadian Prairies. Buried valleys with an extent in excess of 20,000 km beneath the Canadian prairie landscape have been previously interpolated using borehole data; however, they provide only limited insight into the geometry and spatial relationships of these valleys. The collected high-quality geophysical datasets, a threedimensional airborne electromagnetic survey and high resolution seismic profile data provide much greater resolution of buried valley geometry and internal sedimentary architecture of buried valleys. Several generations of valleys at different scales are identified. We interpret multiple erosion surfaces bounding thick diamicton sequences that fill the largest valleys; the youngest valleys are filled with variable sediment types. Three valley morphologies are identified and process origins inferred: 1) regional-scale, extensive, subaerial and pre/interglacial named a-type valley, 2) regional-scale, narrow and mainly proglacial, b-type valley and 3) local-scale, apparently discontinuous, subglacial, g-type valley. Within the glacial sediment stratigraphy filling a-type valleys are thick diamicton sequences bounded by erosional surfaces. The b-type and g-type valleys are filled with variable sediment types. The proglacial b valleys erode bedrock and also occur within the a-type valley fill. Conversely, the g subglacial valleys are observed to crosscut other valleys and may be shallow and wide, or deep and narrow. The reported geophysical datasets supported by borehole data are able to map buried valleys in threedimensions and hence identify the morphologic and stratigraphic relationships that permit improved constraints on process and erosional origin and fill of buried valleys. Results provide insight into the relationship between valleys formed as part of Tertiary fluvial erosion, multiple glaciations, and glaciofluvial events. These data provide significant insights on the distribution and character of potential groundwater reservoirs in Prairie regions.
An analysis of glacial landforms on a regional scale leads to an interpretation of the dynamics o... more An analysis of glacial landforms on a regional scale leads to an interpretation of the dynamics of Late Wisconsinan glaciation on Wollaston Peninsula, Victoria Island, Northwest Territories. The glacial record is dominated by four adjacent belts of landforms: (I) ground moraine (till plains and ice-marginal drainage features), (II) hummocky moraine, (III) lateral and shear moraine, and (IV) streamlined landforms. The landform belts are considered as representing four distinct glacial ice conditions or regimes: (1) ice-margin retreat during extending flow of thin, active ice; (2) marginal ice stagnation following compressional flow; (3) a surging ice margin producing massive shear moraines; and (4) large-scale flooding and mass ice stagnation following a surge. These landform belts were arranged in zones by topographically controlled glacial dynamics, the latter two defining a former ice stream.Glaciological inferences can be extended by examining the sediments and processes that pro...
Silty carbonate till derived from erosion of Paleozoic carbonate and Proterozoic rocks within and... more Silty carbonate till derived from erosion of Paleozoic carbonate and Proterozoic rocks within and adjacent to Hudson Bay covers extensive areas of the Canadian Shield north of Lake Superior. It is hypothesized that this carbonate till could have acted as low-resistance substrata for overriding ice streams by deforming and (or) supporting high subglacial water pressures. Contrary to assumptions presented in some current models for ice flow within the Laurentide Ice Sheet, it need not be assumed that Shield terrain in these areas acted as a rigid bed, generating large basal shear stresses and inhibiting ice flow. Indeed, erratic-dispersal patterns, long-distance glacial transport, and splayed patterns of ice-flow indicators in areas of thick till cover may be better explained by rapid ice-flow events or ice streams, enhanced by the thickness, distribution, impermeability, and susceptibility to deformation of fine carbonate till.
... The outer margin of the Halton drift extends 30 km north to the Oak Ridges Moraine and to the... more ... The outer margin of the Halton drift extends 30 km north to the Oak Ridges Moraine and to the Palgrave Moraine, northwest of the Scarborough Bluffs (Fig. ... The Oak Ridges and PalgraveMoraines mark the northern occupation of late ice from the Lake Ontario basin. Page 3. ...
Growth is widely seen as the means to create employment and achieve economic prosperity. Growth a... more Growth is widely seen as the means to create employment and achieve economic prosperity. Growth also consumes natural resources. As a consequence, growth can create the potential for societal conflict where resources are limited. For example, urban development or aggregate extraction can conflict with ecosystem preservation and recharge zone protection. In the Canadian context, Waterloo Region (the Region) is a classical case study for this potential conflict. Economically, the Region is changing rapidly. While much of the Region’s traditional manufacturing industry has been devastated by globalization, a new high-tech industry has emerged, resulting in considerable urban growth. The provincial government has supported this trend by designating Waterloo Region as one of a number of growth centres in the province, and as a result, the population is expected to increase by 50% over the next 30 years. Growth increases the pressure on the community’s natural resources. In addition to land, the most critical natural resource for the Region is water. Although the Region is situated between two of North America’s Great Lakes, access to potable water from these lakes is complicated and expensive. Fortunately, the Region already has an excellent source of water beneath the urban landscape – the groundwater of the Waterloo Moraine. In addition to providing the Region’s drinking water, the Moraine also assures the ecological health of streams and wetlands, and it supports a healthy agricultural sector in the rural areas. The Moraine water resource is adequate for present use; however, it is also limited. Growth not only increases the demand on water but can potentially diminish the resource itself. Sprawling subdivision developments over the aquifer recharge areas can affect the quantity of water available, urban contaminants such as road salt can impact the groundwater quality and aggregate pits can weaken the protection of the aquifers from contaminants. Consequently, conflict can potentially arise when the growing demand tests the limits of the resource. Water managers at the Region of Waterloo have so far been successful in striking a balance between growth, water use and the protection of the water source, using a multi-faceted approach including demand management, delineating groundwater sensitivity zones and constraining the urbanized area by means of a “countryside line”. The sensitivity zone concept is science-based, while the countryside line has a political origin. The latter concept is being challenged by development interests, which seek to expand residential subdivisions across the countryside line into rural areas that also contain the main recharge areas of the Waterloo Moraine. Allowing urban sprawl into the main Moraine recharge areas has the associated risk of upsetting the recharge-withdrawal balance. The considerable effort to preserve and protect the Region’s water source has produced a large amount of knowledge over the past 40 years, involving different branches of groundwater science. The idea for this Special Issue arose when researchers at the Geological Survey of Canada and the University of Waterloo decided to compile an authoritative source for this body of knowledge, to be readily available to others confronted with similar land-water conflicts. The result is a set of 11 research papers by authors from government, universities and private consultants, all with different backgrounds and expertise, but all with a passion for groundwater. These papers cover both science and societal aspects of groundwater, they are all interrelated, but each stands on its own merit. Frind and Middleton (2014, this issue) examine the Region’s overall strategy for managing the complex Moraine groundwater resource and providing a reliable water source for the growing community. This successful strategy integrates the principles of sustainable water governance with a science-based understanding of the complex Moraine system. Bajc et al. (2014, this issue) lay the foundation for the science of the Waterloo Moraine by unravelling its depositional history during the Quaternary age. Understanding this history and applying a full range of exploratory tools including
Please click here to download the map associated with this article.The Oak Ridges Moraine area, s... more Please click here to download the map associated with this article.The Oak Ridges Moraine area, southern Ontario, includes most of the Greater Toronto Area, which is the most populated region of Canada. The 11,000 km2 region is bounded to the south by Lake Ontario and to the north where Paleozoic bedrock abuts Precambrian Canadian Shield. The area extends 160 km eastward from the Niagara Escarpment, a prominent 100 m high regional bedrock scarp. The surficial sediment is up to 200 m thick, and reveals exposures of the oldest Quaternary sediment in southern Canada. Population growth has caused land use conflicts and increased pressure on groundwater resources. Construction of a regional 3-D geological model of the glacial stratigraphy was needed to support a better understanding of aquifer distribution, scale, and resource potential and protection.Mapping of the regional glacial geomorphology and sediment succession identified a number of distinct landforms: tunnel channels, drumlins, eskers, moraines, and till and lacustrine plains. Using sequence stratigraphic concepts, strata have been grouped into four principal units that unconformably overlie Paleozoic bedrock: Lower sediment, Newmarket Till, Oak Ridges Moraine, and Halton Till.These four Quaternary units plus bedrock have been mapped in the subsurface as a succession of interpolated surfaces using an innovative stratigraphic database-GIS approach. The model-building process involved stratigraphically coding high-quality data, then integrating an extensive and diverse array of subsurface geological and archival datasets using an expert system (geological rules). Stratigraphic data subsets were then extracted and merged with DEM-controlled surface mapping and interpolated in a GIS.
The results of studies of dielectric-barrier discharge (DBD) plasma optical characteristics in mi... more The results of studies of dielectric-barrier discharge (DBD) plasma optical characteristics in mixtures of mercury diiodide vapor, xenon and helium are presented. Regularities in spectral, temporal and energy characteristics of plasma, depending on the partial pressures of the mixture components are established. An average and pulsed radiation power of 0.8 Watts and 293 Watts is reached respectively from the emission volume 111ˑ10-6 m 3 in violet-blue spectral range.
The hypothesis that Oak Ridges Moraine (ORM) formed between converging ice streams requires criti... more The hypothesis that Oak Ridges Moraine (ORM) formed between converging ice streams requires critical testing. Available data (e.g., DEMs, maps, seismic profiles, continuous cores, and pit exposures) are inconsistent with the converging ice stream hypothesis. Combined analysis of landform and subsurface data permits testing the ORM area stratigraphic sequence and sedimentary origin. Stratigraphic data indicate that drumlinized Newmarket Till, incised by N-S-oriented (tunnel) valleys, extends beneath ORM. Thus, streamlining on Newmarket Till is older than ORM and has no direct bearing on its formation. The N-S-trending valleys truncate streamlined Newmarket Till, extend to bedrock, have inset eskers, and occur beneath ORM. Hence, these valleys are older than ORM and have a subglacial rather than a proglacial origin. Overlying the mega-scale lineations (MSLs) and incised channels are topographically elevated (> 300 m asl), ORM glaciofluvial – glaciolacustrine sequences. Its east to ...
Information from a wide range of sources is integrated in a basin analysis of the Wabigoon Basin,... more Information from a wide range of sources is integrated in a basin analysis of the Wabigoon Basin, a Quaternary clay basin located on the Canadian Shield in northwestern Ontario. The basin sediments were deposited between 10.9 ka and 9.5 ka, along the margin of the Rainy Lobe of the Laurentide Ice Sheet, which formed the northern boundary of proglacial Lake Agassiz. The basin architecture is dominated by four major elements: end moraines, eskers, kames and a clay plain, all of which overlie irregular bedrock topography. End moraines, eskers and kames are composed mainly of a fining upward sequence of gravels and sands. The geometry of these sedimentary units, and their sedimentary structures indicates they were deposited mainly by high and low-density turbidity currents, on ice-marginal subaqueous outwash fans. Eskers contain a core of coarse gravel and sand deposited within subglacial meltwater conduits, overlain by subaqueous fan sediments deposited at the conduit mouth. Esker ridg...
In regions formerly covered by continental ice, till sheets may contain distinctive clastic parti... more In regions formerly covered by continental ice, till sheets may contain distinctive clastic particles derived from local bedrock sources such as ore bodies. Such particles, especially in thicker tills, may be distributed in three-dimensional dispersal trains or plumes. Developments in our understanding of glacial erosion, entrainment, and deposition over the past two or three decades help clarify formation of these plumes. Much of the debris in the basal ice of ice sheets is likely incorporated at places where water is freezing onto the base of the ice sheet. This water, largely a product of melting of basal ice further upglacier, has migrated downglacier under the influence of a gradient in the hydraulic potential controlled primarily by the ice surface slope and secondarily by basal topography and thermal regime. Refreezing occurs over a substantial distance along flow, so as the ice moves away from an ore body, material eroded from the body is later elevated above the bed by refr...
Canadian Water Resources Journal / Revue canadienne des ressources hydriques, 2014
ABSTRACT Aquifers of the Waterloo Moraine play a key role as the main source of drinking water fo... more ABSTRACT Aquifers of the Waterloo Moraine play a key role as the main source of drinking water for the Region of Waterloo. For the effective management of this water source, a sound understanding of the aquifers contained within and below the Moraine is essential. Critical knowledge required for this understanding includes the definition of the sediment facies distribution, architectural elements and geological origin of the Quaternary-aged deposits. A basin analysis approach has been applied to geologic data collection and interpretation to unravel the paleogeographic history of the study area and to provide a predictive framework for understanding its geological variability. Coarse (sand and gravel) sediment within the Waterloo Moraine was deposited during a series of high-energy meltwater discharge events from several sediment input corridors (eskers), into a deep, large, ice-supported glacial lake. This depositional setting led to a complex three-dimensional architecture comprising sand-gravel and mud units that are increasingly interbedded away from the multi-directional influx sources around the perimeter of the Moraine. A recently completed digital, three-dimensional geologic model of the area provides details of the various geological units that help refine the understanding of the hydrostratigraphy. This information has improved the understanding of groundwater flow (including interaction between surface and groundwaters) and has provided valuable information critical for source water protection. Information on the distribution, thickness, geometry and properties of these units has resulted in a better understanding of the potential linkages between near-surface recharge areas and deep aquifers across the region. This geological information is important in developing predictive models, for example, determining the location of high transmissivity zones within the moraine. Derivative products such as aquifer vulnerability and recharge maps may help inform policy makers in developing land use and nutrient management plans in the vicinity of well fields and sensitive lands.
Airborne electromagnetic and high resolution seismic geophysical data provide insight into comple... more Airborne electromagnetic and high resolution seismic geophysical data provide insight into complex buried valley geometry and internal sedimentary architecture of buried valleys in the Canadian Prairies. Buried valleys with an extent in excess of 20,000 km beneath the Canadian prairie landscape have been previously interpolated using borehole data; however, they provide only limited insight into the geometry and spatial relationships of these valleys. The collected high-quality geophysical datasets, a threedimensional airborne electromagnetic survey and high resolution seismic profile data provide much greater resolution of buried valley geometry and internal sedimentary architecture of buried valleys. Several generations of valleys at different scales are identified. We interpret multiple erosion surfaces bounding thick diamicton sequences that fill the largest valleys; the youngest valleys are filled with variable sediment types. Three valley morphologies are identified and process origins inferred: 1) regional-scale, extensive, subaerial and pre/interglacial named a-type valley, 2) regional-scale, narrow and mainly proglacial, b-type valley and 3) local-scale, apparently discontinuous, subglacial, g-type valley. Within the glacial sediment stratigraphy filling a-type valleys are thick diamicton sequences bounded by erosional surfaces. The b-type and g-type valleys are filled with variable sediment types. The proglacial b valleys erode bedrock and also occur within the a-type valley fill. Conversely, the g subglacial valleys are observed to crosscut other valleys and may be shallow and wide, or deep and narrow. The reported geophysical datasets supported by borehole data are able to map buried valleys in threedimensions and hence identify the morphologic and stratigraphic relationships that permit improved constraints on process and erosional origin and fill of buried valleys. Results provide insight into the relationship between valleys formed as part of Tertiary fluvial erosion, multiple glaciations, and glaciofluvial events. These data provide significant insights on the distribution and character of potential groundwater reservoirs in Prairie regions.
An analysis of glacial landforms on a regional scale leads to an interpretation of the dynamics o... more An analysis of glacial landforms on a regional scale leads to an interpretation of the dynamics of Late Wisconsinan glaciation on Wollaston Peninsula, Victoria Island, Northwest Territories. The glacial record is dominated by four adjacent belts of landforms: (I) ground moraine (till plains and ice-marginal drainage features), (II) hummocky moraine, (III) lateral and shear moraine, and (IV) streamlined landforms. The landform belts are considered as representing four distinct glacial ice conditions or regimes: (1) ice-margin retreat during extending flow of thin, active ice; (2) marginal ice stagnation following compressional flow; (3) a surging ice margin producing massive shear moraines; and (4) large-scale flooding and mass ice stagnation following a surge. These landform belts were arranged in zones by topographically controlled glacial dynamics, the latter two defining a former ice stream.Glaciological inferences can be extended by examining the sediments and processes that pro...
Silty carbonate till derived from erosion of Paleozoic carbonate and Proterozoic rocks within and... more Silty carbonate till derived from erosion of Paleozoic carbonate and Proterozoic rocks within and adjacent to Hudson Bay covers extensive areas of the Canadian Shield north of Lake Superior. It is hypothesized that this carbonate till could have acted as low-resistance substrata for overriding ice streams by deforming and (or) supporting high subglacial water pressures. Contrary to assumptions presented in some current models for ice flow within the Laurentide Ice Sheet, it need not be assumed that Shield terrain in these areas acted as a rigid bed, generating large basal shear stresses and inhibiting ice flow. Indeed, erratic-dispersal patterns, long-distance glacial transport, and splayed patterns of ice-flow indicators in areas of thick till cover may be better explained by rapid ice-flow events or ice streams, enhanced by the thickness, distribution, impermeability, and susceptibility to deformation of fine carbonate till.
... The outer margin of the Halton drift extends 30 km north to the Oak Ridges Moraine and to the... more ... The outer margin of the Halton drift extends 30 km north to the Oak Ridges Moraine and to the Palgrave Moraine, northwest of the Scarborough Bluffs (Fig. ... The Oak Ridges and PalgraveMoraines mark the northern occupation of late ice from the Lake Ontario basin. Page 3. ...
Growth is widely seen as the means to create employment and achieve economic prosperity. Growth a... more Growth is widely seen as the means to create employment and achieve economic prosperity. Growth also consumes natural resources. As a consequence, growth can create the potential for societal conflict where resources are limited. For example, urban development or aggregate extraction can conflict with ecosystem preservation and recharge zone protection. In the Canadian context, Waterloo Region (the Region) is a classical case study for this potential conflict. Economically, the Region is changing rapidly. While much of the Region’s traditional manufacturing industry has been devastated by globalization, a new high-tech industry has emerged, resulting in considerable urban growth. The provincial government has supported this trend by designating Waterloo Region as one of a number of growth centres in the province, and as a result, the population is expected to increase by 50% over the next 30 years. Growth increases the pressure on the community’s natural resources. In addition to land, the most critical natural resource for the Region is water. Although the Region is situated between two of North America’s Great Lakes, access to potable water from these lakes is complicated and expensive. Fortunately, the Region already has an excellent source of water beneath the urban landscape – the groundwater of the Waterloo Moraine. In addition to providing the Region’s drinking water, the Moraine also assures the ecological health of streams and wetlands, and it supports a healthy agricultural sector in the rural areas. The Moraine water resource is adequate for present use; however, it is also limited. Growth not only increases the demand on water but can potentially diminish the resource itself. Sprawling subdivision developments over the aquifer recharge areas can affect the quantity of water available, urban contaminants such as road salt can impact the groundwater quality and aggregate pits can weaken the protection of the aquifers from contaminants. Consequently, conflict can potentially arise when the growing demand tests the limits of the resource. Water managers at the Region of Waterloo have so far been successful in striking a balance between growth, water use and the protection of the water source, using a multi-faceted approach including demand management, delineating groundwater sensitivity zones and constraining the urbanized area by means of a “countryside line”. The sensitivity zone concept is science-based, while the countryside line has a political origin. The latter concept is being challenged by development interests, which seek to expand residential subdivisions across the countryside line into rural areas that also contain the main recharge areas of the Waterloo Moraine. Allowing urban sprawl into the main Moraine recharge areas has the associated risk of upsetting the recharge-withdrawal balance. The considerable effort to preserve and protect the Region’s water source has produced a large amount of knowledge over the past 40 years, involving different branches of groundwater science. The idea for this Special Issue arose when researchers at the Geological Survey of Canada and the University of Waterloo decided to compile an authoritative source for this body of knowledge, to be readily available to others confronted with similar land-water conflicts. The result is a set of 11 research papers by authors from government, universities and private consultants, all with different backgrounds and expertise, but all with a passion for groundwater. These papers cover both science and societal aspects of groundwater, they are all interrelated, but each stands on its own merit. Frind and Middleton (2014, this issue) examine the Region’s overall strategy for managing the complex Moraine groundwater resource and providing a reliable water source for the growing community. This successful strategy integrates the principles of sustainable water governance with a science-based understanding of the complex Moraine system. Bajc et al. (2014, this issue) lay the foundation for the science of the Waterloo Moraine by unravelling its depositional history during the Quaternary age. Understanding this history and applying a full range of exploratory tools including
Please click here to download the map associated with this article.The Oak Ridges Moraine area, s... more Please click here to download the map associated with this article.The Oak Ridges Moraine area, southern Ontario, includes most of the Greater Toronto Area, which is the most populated region of Canada. The 11,000 km2 region is bounded to the south by Lake Ontario and to the north where Paleozoic bedrock abuts Precambrian Canadian Shield. The area extends 160 km eastward from the Niagara Escarpment, a prominent 100 m high regional bedrock scarp. The surficial sediment is up to 200 m thick, and reveals exposures of the oldest Quaternary sediment in southern Canada. Population growth has caused land use conflicts and increased pressure on groundwater resources. Construction of a regional 3-D geological model of the glacial stratigraphy was needed to support a better understanding of aquifer distribution, scale, and resource potential and protection.Mapping of the regional glacial geomorphology and sediment succession identified a number of distinct landforms: tunnel channels, drumlins, eskers, moraines, and till and lacustrine plains. Using sequence stratigraphic concepts, strata have been grouped into four principal units that unconformably overlie Paleozoic bedrock: Lower sediment, Newmarket Till, Oak Ridges Moraine, and Halton Till.These four Quaternary units plus bedrock have been mapped in the subsurface as a succession of interpolated surfaces using an innovative stratigraphic database-GIS approach. The model-building process involved stratigraphically coding high-quality data, then integrating an extensive and diverse array of subsurface geological and archival datasets using an expert system (geological rules). Stratigraphic data subsets were then extracted and merged with DEM-controlled surface mapping and interpolated in a GIS.
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