Understanding Canadian Cordillera crustal and upper-mantle structure with joint Bayesian inversion of receiver functions and surface-wave dispersion curves
Date
2020-08-20
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Abstract
The accretion of exotic terranes onto the stable Northern American craton during the formation of the Northern Canadian Cordillera (NCC) generated complex structure on a crustal and lithospheric scale. Without making significant model-parametrization assumptions, inverting for structure is challenging. The Bayesian approach quantifies uncertainty due to non-uniqueness of the solution and can avoid subjective choice in model parameterization. Jointly inverting receiver-functions and surface-wave dispersion curves constrains shear-wave velocity structure. With this inversion method, I study the spatial variability of major lithospheric discontinuities, specifically of the Mohoroviciˇ c discontinuity (Moho) and lithosphere-asthenosphere boundary (LAB), along a transect from Whitehorse to Toad River. Results show a flat Moho across the NCC at ∼ 34-km depth and a heterogeneous LAB with depths between 70- and 100-km depth. Beneath the LAB, I observe a significant low-velocity zone with shear-wave velocities as low as ∼ 3.0 km/s. Only the presence of partial melting of 1.5–2.5% can explain these Vs reductions.
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Keywords
Seismology, Bayesian Inference, Lithosphere, Northern Canadian Cordillera, Joint Inversion
Citation
Smale, J. (2020). Understanding Canadian Cordillera crustal and upper-mantle structure with joint Bayesian inversion of receiver functions and surface-wave dispersion curves (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.