Quantitative constraints on the lithospheric mantle discontinuity structure in eastern Canada from joint analysis of receiver function and surface wave data

Previous work has suggested that the Archean craton of central and eastern Canada contains a number of relict slabs, frozen in and radiating out from the center. This observation has been used to suggest that the craton's existence is due to the formation and dying out of ancient (~2 Ga) subduction zones at the craton edges in progressive Wilson cycles, leaving a chemically depleted and buoyant slab after each stage. Miller & Eaton (2010) used teleseismic S receiver functions to image a deep (200-260 km) sharp lithosphere-asthenosphere boundary and a number of negative polarity shallower, mid-lithospheric discontinuities. However, noise in the data and insufficient sampling from only 8 seismic stations meant that the discontinuities could only be interpreted using comparisons with results based on surface wave and heat flow analyses. To better understand the discontinuity structure across central and eastern Canada, we utilise data from a combination of 32 permanent and temporary broadband stations including those from the HuBLE experiment. From this extended dataset we attempt to constrain evidence for the observed discontinuities more quantitatively by combining both P and S receiver functions with Rayleigh wave phase velocity data in Monte Carlo based joint inversions for shear wave velocity structure. The crustal thickness and velocity is initially constrained by results from active source experiments and stacking of receiver functions. Our Monte Carlo approach allows us to investigate uncertainty in the Vp, density and attenuation parameters on the inferred Vs result and discontinuities, allowing for better constraints on recently reported internal structure of continental lithosphere in both Canada and other cratonic regions.