3-D crust and mantle structure in southern Ontario, Canada via receiver function imaging

•3-D coverage of crust and mantle in S. Ontario via complementary imaging methods•Detection of layered crust with breaks corresponding to major structural features•Ottawa-Bonnechère Graben is a crustal-scale feature that offsets the Moho.•Mississauga Domain is bounded by crustal-scale faults.•Upper mantle contains dipping features possibly related to subduction remnants.

A teleseismic data set from the POLARIS project is used to obtain 3-D images of southern Ontario using two imaging techniques: scattering tomography and common-conversion-point stacking. The resulting images reveal a layered crust, the layering being interrupted by discontinuities associated with major crustal-scale faulting. Breaks in crustal continuity and Moho deflections associated with the Ottawa-Bonnechère Graben indicate that the graben is associated with faulting on a whole crust scale. We also detect similar discontinuities across the Mississauga Domain, supporting the previous interpretation that the domain is bounded by crustal-scale faults. We locate discontinuous sub-lithospheric negative-polarity arrivals which indicate complex three-dimensional structures within the lithosphere and may be associated with subduction remnants or a mid-lithosphere discontinuity.