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TitleMoho variations across the northern Canadian cordillera
AuthorAudet, P; Schutt, D L; Schaeffer, A JORCID logo; Estève, C; Aster, R C; Cubley, J F
SourceSeismological Research Letters vol. 91, issue 6, 2020 p. 3076-3085,
Alt SeriesNatural Resources Canada, Contribution Series 20200606
PublisherSeismological Society of America
Mediapaper; on-line; digital
File formatpdf; html
ProvinceNorthwest Territories; Yukon
NTS94M; 94N; 94O; 94P; 104M; 104N; 104O; 104P; 114B; 114C; 95; 105; 115; 96; 106; 116; 117A; 107A; 107B; 97A; 97B
Lat/Long WENS-141.0000 -121.0000 70.0000 60.3333
SubjectsScience and Technology; tectonics; faults, strike-slip; sea level changes; sea level fluctuations; crustal studies; Northern Canadian Cordillera; Moho
Illustrationslocation maps; graphs; diagrams
Released2020 11 01
AbstractMoho morphology in orogens provides important constraints on the rheology and density structure of the crust and underlying mantle. Previous studies of Moho geometry in the northern Canadian Cordillera (NCC) using very sparse seismic data have indicated a flat and shallow (~ 30-35 km) Moho, despite an average elevation of > 1000 m above sea level attributable to increased thermal buoyancy and lower crustal flow due to elevated temperatures. We estimate Moho depth using receiver functions from an expanded dataset incorporating 173 past and recently deployed broadband seismic stations, including the EarthScope Transportable Array, Mackenzie Mountains transect, and other recent deployments. We determine Moho depths in the range 27-43 km, with mean and standard deviations of 33.0 and 3.0 km, respectively, and note thickened crust beneath high-elevation seismogenic regions. In the Mackenzie Mountains, thicker crust is interpreted as due to crustal stacking from thrust sheet emplacement. The edge of this region of thickened crust is interpreted to delineate the extent of the former Laurentian margin beneath the NCC and is associated with a transition from thrust to strike-slip faulting observed in regional seismicity. More geographically extensive seismograph deployments at EarthScope Transportable Array density and scale will be required to further extend crustal-scale and lithosphere-scale imaging in western Canada.

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