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| Great Slave Lake shear zone | |
|---|---|
| Name | Great Slave Lake shear zone |
| Type | crustal shear zone |
| Location | Northwest Territories, Canada |
| Coordinates | 63°N 114°W |
| Region | Canadian Shield |
| Age | Paleoproterozoic |
| Orogeny | Trans-Hudson Orogen |
Great Slave Lake shear zone The Great Slave Lake shear zone is a major Paleoproterozoic crustal-scale shear zone in the Canadian Shield that transects the region adjacent to Great Slave Lake and influences the terrane boundaries of the Northwest Territories. It is a crustal structure linked to Paleoproterozoic terrane accretion and continental assembly during the Trans-Hudson Orogeny, and it has been the focus of structural, metamorphic, and economic geology studies owing to its role in deformation, metamorphism, and mineralizing fluid pathways.
The shear zone lies within the western Canadian Shield, intersecting provinces and districts associated with Yellowknife, Hay River, Fort Resolution, Wekʼèezhìı (Tlicho), and adjacent to lithotectonic domains such as the Slave Craton, Taltson Magmatic Zone, Buffalo Head Terrane, and the Hearne Craton. It represents a first-order crustal discontinuity comparable in scale to structures studied in the context of the Trans-Hudson Orogen, Superior Province, and other Archean–Paleoproterozoic collision belts such as the Kaapvaal Craton–Zimbabwe Craton junction and the Labrador Trough.
The regional framework includes the Slave Craton to the north, the Buffalo Head Terrane and Paleoproterozoic arcs to the south, and the broader framework of the Canadian Shield and adjacent tectonic elements involved in the Trans-Hudson Orogeny. The shear zone cuts granitoids, greenstone belts, metasedimentary sequences, and metavolcanic rocks that have affinities with units mapped in the Slave Province and correlate with terranes exposed in the Archean and Paleoproterozoic provinces. Nearby structural features and provinces often invoked in regional syntheses include the Rae Craton, Hearne Craton, Wopmay Orogen, and the Slave Structural Province.
The zone displays mylonitic fabrics, large-scale foliation, shear bands, and ductile-brittle shear zones, with kinematics that record transcurrent and transpressional motions comparable to strain patterns observed along the San Andreas Fault and palaeostructures like the Moine Thrust. Kinematic indicators include S-C fabrics, asymmetric porphyroclasts, and oblique-slip indicators consistent with dextral and locally sinistral movements during progressive deformation. The structural architecture includes steep to moderate planar fabrics, anastomosing shear surfaces, and cross-cutting brittle faults that link to regional lineaments studied in the context of geological mapping campaigns by agencies such as the Geological Survey of Canada and provincial surveys.
Geochronological constraints derive from U-Pb zircon and monazite dating, Ar-Ar chronometry, and Sm-Nd isotopic studies, placing major deformation and metamorphism within the Paleoproterozoic interval associated with the Trans-Hudson Orogen and Mesoproterozoic to Neoproterozoic overprints in some domains. Metamorphic grades range from greenschist to amphibolite facies, with local granulite-facies relics analogous to metamorphic conditions documented in the Kola Peninsula and parts of the Canadian Shield. Isotopic studies often cite methods and laboratories associated with institutions such as the Geological Survey of Canada, University of Toronto, University of Alberta, and international comparators like the Smithsonian Institution for processing and interpretation.
The shear zone is a prospective corridor for mineralizing fluids, hosting or controlling occurrences of gold, base metals, rare earth elements, and uranium in structurally prepared lithologies similar to mineralization styles seen in the Yellowknife greenstone belt, the Nunavut gold camps, and along shear-hosted lodes akin to those in the Abitibi Greenstone Belt. Exploration programs by companies and agencies such as De Beers, Rio Tinto, Agnico Eagle Mines, and junior explorers have targeted structural traps, vein systems, and alteration halos. Mineral deposits in the region are evaluated by regulatory frameworks and institutions including the Ontario Geological Survey (for regional analogues), the Northwest Territories Geological Survey, and private-sector consultancies.
Aeromagnetic, gravity, and seismic reflection surveys have imaged the shear zone’s subsurface geometry, with methods and datasets produced by the Geological Survey of Canada, commercial contractors, and academic consortia. Remote sensing using multispectral and hyperspectral platforms, as well as satellite missions like Landsat, ASTER, and radar surveys comparable to RADARSAT have aided lithological discrimination, lineament mapping, and alteration detection. Regional geophysical frameworks integrate datasets comparable to studies in the Athabasca Basin, Flin Flon Belt, and Superior Province to constrain crustal-scale architecture.
Systematic mapping and interpretation began with early 20th-century surveys and intensified during Paleoproterozoic orogeny syntheses by the Geological Survey of Canada and university-led field programs from McGill University, University of Western Ontario, Queen's University, and University of Calgary. Key contributors and researchers have included Canadian and international structural geologists, metamorphic petrologists, and economic geologists who published mapping reports, theses, and peer-reviewed articles in outlets associated with institutions such as the Royal Society of Canada and international journals. Continued integration of geochronology, isotopic studies, geophysics, and remote sensing keeps the zone an active focus for understanding craton margin evolution, mineral prospectivity, and continental assembly processes.
Category:Geology of the Northwest Territories