Geology of the Cordilleran Orogen in Canada

Gabrielse, H; Yorath, C J

doi:10.4095/134069

Cited by 109 publications

(62 citation statements)

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“…This is bound farther west (main ranges) in British Columbia by the Rocky Mountain Trench. The final shape of the Alberta foreland basin developed by downward flexing of the Canadian Shield due to lithospheric loading and isostatic flexure in a retro-arc setting (Leckie and Smith, 1992;English and Johnston, 2004), together with the sediments derived from the developing Canadian Cordillera (Gabrielse and Yorath, 1989). The Alberta Basin consists of a nearly undeformed sedimentary wedge (Fig.…”

Section: General Workflow Of Model Calibrationmentioning

confidence: 99%

3-D geomechanical–numerical model of the contemporary crustal stress state in the Alberta Basin (Canada)

Reiter

Heidbach

2014

Solid Earth

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Abstract. In the context of examining the potential usage of safe and sustainable geothermal energy in the Alberta Basin, whether in deep sediments or crystalline rock, the understanding of the in situ stress state is crucial. It is a key challenge to estimate the 3-D stress state at an arbitrarily chosen point in the crust, based on sparsely distributed in situ stress data.To address this challenge, we present a large-scale 3-D geomechanical-numerical model (700 km×1200 km×80 km) from a large portion of the Alberta Basin, to provide a 3-D continuous quantification of the contemporary stress orientations and stress magnitudes. To calibrate the model, we use a large database of in situ stress orientation (321 S Hmax ) as well as stress magnitude data (981 S V , 1720 S hmin and 2 (+11) S Hmax ) from the Alberta Basin. To find the best-fit model, we vary the material properties and primarily the displacement boundary conditions of the model. This study focusses in detail on the statistical calibration procedure, because of the large amount of available data, the diversity of data types, and the importance of the order of data tests.The best-fit model provides the total 3-D stress tensor for nearly the whole Alberta Basin, and allows estimation of stress orientation and stress magnitudes in advance of any well. First-order implications for the well design and configuration of enhanced geothermal systems are revealed. Systematic deviations of the modelled stress from the in situ data are found for stress orientations in the Peace River and the Bow Island Arch as well as for leak-off test magnitudes.

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Section: General Workflow Of Model Calibrationmentioning

confidence: 99%

3-D geomechanical–numerical model of the contemporary crustal stress state in the Alberta Basin (Canada)

Reiter

Heidbach

2014

Solid Earth

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“…The Western Ranges form the western boundary of the Foreland Belt, which is characterized by its thin-skinned style of deformation with broad, regional folds that overlie shallow-dipping decollements. Together, the Dogtooth and Western Ranges represent a structural transition from the polydeformed, greenschist to amphibolite grade rocks that comprise the Selkirk Complex in the west to the fault-dominated, foreland-type tectonism that affects subgreenschist assemblages in the platform carbonates of the Rocky Mountain Main and Front Ranges [Gabrielse and Yorath, 1992].…”

Section: Regional Overviewmentioning

confidence: 99%

New evidence for syntectonic fluid migration across the hinterland‐foreland transition of the Canadian Cordillera

2002

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[1] Oxygen isotope data from syntectonic veins, thrust faults, and wall rocks suggest that fluids infiltrated the Western Ranges of the Rocky Mountain foreland from deeper rocks of the Dogtooth Range during Mesozoic contraction. This signifies the first such evidence for kilometerscale fluid migration at the hinterland-foreland transition of the Canadian Cordillera. Fluid infiltration resulted in isotopic depletion in wall rocks and isotopic disequilibrium between veins (fluid) and their host rocks downstream of a lithologic, structural, and isotopic shift between predominantly siliciclastic (Dogtooth Range) and calcareous (Western Ranges) sequences. The shift corresponds with an average d 18 O that is 3.0% higher in the Western Ranges. In the Dogtooth Range, atypically low carbonate values (15.6% ± 0.8% (VSMOW)), and the consistency with which vein signatures approach the average bulk rock d18 O of individual outcrops indicate fluid buffering by a siliciclastic reservoir and outcrop-scale (10 -100 m) fluid circulation. In contrast, rocks and veins in the Western Ranges exhibit a gradational increase in d18 O that extends !14 km eastward and up section from the isotopic shift and possess values that are below or at the low end of typical carbonate compositions (16.2 -20.9% (VSMOW)). Furthermore, veins systematically exhibit lower oxygen values than their host rocks; this implies that the fluids that entered the Western Ranges were in modest disequilibrium with the rocks through which they flowed. We use a one-dimensional reactive transport model to infer that rocks in the Western Ranges experienced a time-integrated fluid flux of 1.1 Â 10 5 mol H 2 O cm À2 (%2.4 Â 10 6 cm 3 cm À2 ) and sluggish reaction kinetics during the flow event.

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“…The recent DNAG (Decade of North American Geology) volume on the Canadian Cordillera (GABRIELSE and YORATH, 1991a) gives excellent background information on the tectonic framework of British Columbia (B.C.). It is within North America's Cordillera that terrane concepts of crustal accretion were first developed (CONEY et al, 1980).…”

Section: Introductionmentioning

confidence: 99%

The BC87 Dataset: Tectonic Setting, Previous EM Results, and Recorded MT Data.

Jones

1993

J. geomagn. geoelec

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As part of project LITHOPROBE, magnetotelluric data were acquired at twenty-seven sites along a 150 km east-west profile in southeastern British Columbia straddling the complex tectonic boundary between ancestral North American rocks and those of the easternmost accreted terranes. These data, named the BC87 dataset, display complex effects due to both three-dimensional induction and galvanic scattering at virtually all scale sizes, from that of the electrode array (<50 m) to that of the large plutonic Nelson batholith (150x50 km surface extent). The dataset was distributed widely in order to compare and contrast different schemes for extracting the underlying predominant two-dimensional structure, and to test differing interpretational algorithms on data from a complex crystalline terrane. The MT data are shown, and the tectonic setting described. Also, seismic and previous EM studies of the region are described.

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Geology of the Cordilleran Orogen in Canada

Cited by 109 publications

References 0 publications

3-D geomechanical–numerical model of the contemporary crustal stress state in the Alberta Basin (Canada)

3-D geomechanical–numerical model of the contemporary crustal stress state in the Alberta Basin (Canada)

New evidence for syntectonic fluid migration across the hinterland‐foreland transition of the Canadian Cordillera

The BC87 Dataset: Tectonic Setting, Previous EM Results, and Recorded MT Data.

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