Receiver Function Constraints in the Western ChurchillProvince, Northern Canada

The Western Churchill Province (WCP) of northern Canada is a complex assemblage of Archean to Proterozoic crust, yet its lithospheric architecture remains incompletely constrained. We present a comprehensive receiver function study of crustal structure across the WCP using approximately 5,000 high-quality P-wave receiver functions recorded at 39 broadband seismic stations between 2000 and 2025. Data quality was ensured using DeepRFQC, a machine-learning–based automated quality control framework.

Crustal thickness and bulk composition were estimated through H–κ stacking, while harmonic decomposition and differential evolution inversion of receiver functions using RAYSUM were applied to investigate crustal anisotropy, dipping interfaces, and seismic velocity structure. The mean Moho depth across the WCP is 40 ± 5 km, with pronounced lateral variability. The deepest Moho is observed in the northernmost and southernmost regions, whereas the central WCP exhibits comparatively thinner crust.

Bulk VP/VS ratios are relatively uniform (1.76–1.79), consistent with predominantly felsic crust, although elevated values near northern Hudson Bay suggest localized mafic intrusions. Harmonic decomposition reveals coherent azimuthal patterns indicative of crustal anisotropy and dipping structures, with mid-crustal discontinuities identified at approximately 9 and 30 km depth.

The orientations of harmonic components correlate with regional magnetic anomalies and independent SKS shear-wave splitting measurements, implying strong coupling between crustal structure and lithospheric mantle fabric. Comparisons with Bouguer gravity anomalies indicate that gravity variations are primarily controlled by subsurface density variations, as reflected in VP/VS ratios, rather than by Moho topography. These results provide new constraints on the crustal architecture and lithospheric coherence of the Western Churchill Province.