Evolution of faulting and paleo-stress field within the Ottawa graben, Canada

Rimando, Rolly E.; Benn, K.

doi:10.1016/j.jog.2005.01.003

Cited by 38 publications

(39 citation statements)

References 48 publications

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“…Permeability reduction at the Christie Lake lineament is discussed later. The north-facing topographic break, the northwest lineament trend, and the vertical northwest-striking fracture set suggest that the faulted Christie Lake lineament is part of the Ottawa-Bonnechere graben system (Kumarapeli, 1978;Rimando and Benn, 2005). Northwesttrending lineaments in eastern Ontario, which decrease in frequency away from the center of the graben, have been previously interpreted as part of the Ottawa-Bonnechere graben (Spitzer, 1981).…”

Section: Discussionmentioning

confidence: 98%

“…1A; Kay, 1942). The graben is considered to be a Neoproterozoic failed arm of a triple junction that was repeatedly reactivated by Phanerozoic tectonism (Kumarapeli, 1978(Kumarapeli, , 1981Rimando and Benn, 2005). The southern half of the graben is characterized by north-facing topographic breaks with down-thrown north-side hanging walls.…”

Section: Regional Geology and Hydrologymentioning

confidence: 99%

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Identifying watershed-scale barriers to groundwater flow: Lineaments in the Canadian Shield

Gleeson

Novakowski

2009

Geological Society of America Bulletin

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Lineament identifi cation is a standard but controversial hydrogeologic practice. In this study, we present a rigorous examination of the hydrology of lineaments in a crystalline bedrock setting. Lineaments are reinterpreted as watershed-scale hydraulic barriers, in contrast to previous interpretations as fractured conduits that focus recharge and fl ow. In the study area, an ~900 km 2 watershed underlain by the granitic and gneissic terrain of the Canadian Shield, bedrock lineaments are associated with linear lake shores and perennial wetland complexes. Lineaments were identifi ed using a robust multi-image method and characterized by remote sensing, fracture mapping, drilling, hydraulic characterization, and numerical simulation of a coupled groundwater-surface-water system. Results indicate that two principal lineament sets are oriented parallel to fracture and fault orientations, and thus lineaments are interpreted as structural features, either fault zones or fracture zones with limited displacement. Faulted lineaments are more effectively identifi ed by digital elevation model (DEM) topographic data rather than Landsat tonal imagery. Hydrogeological characterization and geomatic data indicate that the fractured bedrock underlying lineaments is composed of poorly connected zones of reduced permeability due to fault zone and/or fl uid fl ow processes. Field data and numerical simulations suggest that lineament areas are barriers to recharge and fl ow in this setting as a result of permeability reduction. Integrated data sets and models of lineament permeability that are geologically realistic result in a better understanding of fractured bedrock aquifers and patterns of fl uid fl ow in the brittle uppermost crust.

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Section: Discussionmentioning

confidence: 98%

Section: Regional Geology and Hydrologymentioning

confidence: 99%

Identifying watershed-scale barriers to groundwater flow: Lineaments in the Canadian Shield

Gleeson

Novakowski

2009

Geological Society of America Bulletin

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“…The southern and northern walls of the graben are parallel to the WNW-ESE trend of the end of the Grenvillian orogeny. This orientation is also reflected in other regional structures, such as the Ottawa graben (Kumarapeli 1981;Rimando & Benn 2005) and the transform faults in both Canada and United States (Kumarapeli 1970;Thomas 1991). The Kenogami uplands are limited to the south and to the north by the Kenogami and the Tchitogama Lakes, respectively ( Fig.…”

Section: The Kenogami Uplandsmentioning

confidence: 96%

Structural hydrogeology in the Kenogami uplands, Quebec, Canada /

Silva¹

2012

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Characterizing the joint system is a very significant component of investigations on fractured rock aquifers, as the secondary porosity controls the groundwater flow. It is also important to analyze the types of interactions between the joints, e.g., the types of termination and the dominancy of a certain joint set, since such information helps to understand the tectonic events that were responsible for the generation of the joint systems in the aquifer. Moreover, the current stress field is usually the most significant in controlling joint aperture, which plays a major role in groundwater flow.The main objective of this work is to characterize an aquifer in fractured crystalline rocks with a fairly homogeneous lithology, defining a hydrogeological model of the study area, through structural surveys at different scales and hydrogeologic data analyses. This study was carried out in the Kenogami uplands, within the Saguenay graben, Quebec. It aimed to answer the following questions: (1) is there a structured joint system in the bedrock, that is, is it possible to identify preferential joint orientations and structural domains? (2) Can joint systems be defined at different scales, e.g. regional and local scales? If yes, are there any relationships between the systems observed at different scales? (3) Can any correlation between the joint system(s) and the past and present stress fields be identified? (4) Is there a relationship between the hydrogeological properties obtained from boreholes and the joint system(s)?The structural survey involved three main phases. First, a characterization at the regional scale of the joint system is derived from air photo interpretation, lineament analysis, and a general field survey at selected sites. The latter involves the investigation IV of the spatial distribution of the main joint sets, and the study of the relative ages of joint sets and past stress field components conducted on horizontal outcrops. Second, a detailed structural survey of selected road cuts was carried out to define and characterize the main joint sets that compose the joint system in the study area. Third, the realization of geophysical borehole logging provided valuable information at depth, especially regarding subhorizontal joint sets. These steps allowed to answer the questions proposed in the beginning of this research.This project allowed the characterization of an aquifer in fractured crystalline rocks, regarding the following aspects: joint systems at different scales, past stress fields, hydraulic properties and the possible relationships between these parameters. The methodology adopted may be applied to other studies on fractured rock aquifers.Finally, a conceptual model was developed for the fractured rock aquifer in the Kenogami uplands, using the unit block approach. This model may be extrapolated to a regional scale, and it reflects the predominance of the subvertical joints in the study area.Other contributions from this work include the introduction of procedures for applying Terzag...

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“…The Ottawa-Bonnechere Graben is characteristic of a failed arm in a triple junction rift system that was generated during Iapetan rifting. This structure transects through the sedimentary rocks of the St. Lawrence Lowlands into the basement Precambrian rocks (Bélanger 1998), and is a zone of large, down-dropped blocks that extend from Montréal, north through Ottawa, and eventually branch north and west (Wilson 1964;Rimando and Benn 2005) as shown in Fig. 3.…”

Section: Overview Of the Seismic Hazardmentioning

confidence: 99%

Applying the HAZUS-MH software tool to assess seismic risk in downtown Ottawa, Canada

2009

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The aim of this paper is to present earthquake loss estimations for a portion of downtown Ottawa, Canada, using the HAZUS-MH (Hazards United States Multi-Hazard) software tool. The assessment is performed for a scenario earthquake of moment magnitude 6.5, at an epicentral distance of 15 km, occurring during business hours. A level 2 HAZUS-MH analysis was performed where the building inventory, microzonation studies, and site-specific ground motion hazard maps (2% exceedence probability in 50 years) were all improved based on local information. All collected data were assembled into a set of standard geodatabases that are compatible with the HAZUS-MH software using a GISspecific procedure. The results indicate that the greatest losses are expected in unreinforced masonry buildings and commercial buildings. Sensitivity studies show that soil classes, the vulnerability of schools, and the spatial scale of loss estimations are also important factors to take into account.

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Evolution of faulting and paleo-stress field within the Ottawa graben, Canada

Cited by 38 publications

References 48 publications

Identifying watershed-scale barriers to groundwater flow: Lineaments in the Canadian Shield

Identifying watershed-scale barriers to groundwater flow: Lineaments in the Canadian Shield

Structural hydrogeology in the Kenogami uplands, Quebec, Canada /

Applying the HAZUS-MH software tool to assess seismic risk in downtown Ottawa, Canada

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