Architecture of the crust and uppermost mantle in the northern Canadian Cordillera from receiver functions - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research : Solid Earth Année : 2017

Architecture of the crust and uppermost mantle in the northern Canadian Cordillera from receiver functions

Alizia Tarayoun
  • Fonction : Auteur
  • PersonId : 1026723
Stephane Mazzotti

Résumé

The northern Canadian Cordillera (NCC) is an active orogenic belt in northwestern Canada characterized by deformed autochtonous and allochtonous structures that were emplaced in successive episodes of convergence since the Late Cretaceous. Seismicity and crustal deformation are concentrated along corridors located far (>200 to ~800 km) from the convergent plate margin. Proposed geodynamic models require information on crust and mantle structure and strain history, which are poorly constrained. We calculate receiver functions using 66 broadband seismic stations within and around the NCC and process them to estimate Moho depth and P-to-S velocity ratio (Vp/Vs) of the Cordilleran crust. We also perform a harmonic decomposition to determine the anisotropy of the subsurface layers. From these results, we construct simple seismic velocity models at selected stations and simulate receiver function data to constrain crust and uppermost mantle structure and anisotropy. Our results indicate a relatively flat and sharp Moho at 32 ± 2 km depth and crustal Vp/Vs of 1.75 ± 0.05. Seismic anisotropy is pervasive in the upper crust and within a thin (~10–15 km thick) sub-Moho layer. The modeled plunging slow axis of hexagonal symmetry of the upper crustal anisotropic layer may reflect the presence of fractures or mica-rich mylonites. The subhorizontal fast axis of hexagonal anisotropy within the sub-Moho layer is generally consistent with the SE-NW orientation of large-scale tectonic structures. These results allow us to revise the geodynamic models proposed to explain active deformation within the NCC.
Fichier principal
Vignette du fichier
Tarayoun_et_al-2017-Journal_of_Geophysical_Research__Solid_Earth.pdf (8.25 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-01685550 , version 1 (16-01-2018)

Identifiants

Citer

Alizia Tarayoun, Pascal Audet, Stephane Mazzotti, Azadeh Ashoori. Architecture of the crust and uppermost mantle in the northern Canadian Cordillera from receiver functions. Journal of Geophysical Research : Solid Earth, 2017, 122 (7), pp.5268-5287. ⟨10.1002/2017JB014284⟩. ⟨hal-01685550⟩
202 Consultations
113 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More