Mapping the North American thermal lithospheric structure through integrated geophysical –petrological inversion of surface wave data

Here we present a new North America’s lithospheric thermal and compositional model
constrained by integrated geophysical – lithological inversion of Rayleigh and Love surface
wave dispersion curves, supplemented by other geophysical data and models: surface heat flow
and average temperature, topography, Moho depth, P-wave seismic crustal velocities, and
sedimentary thickness. The dispersion curves cover North America with a 0.5 x 0.5 degree
spacing, with periods logarithmically increasing from 8 to 400 s. The curves are constructed by
merging dispersion curves from five different datasets: USANT15 (Ekstrom, 2017), FCL
(Schmandt et al., 2015), NA2014 (Schaeffer & Lebedev, 2014), NAT2020 (Celli et al., 2021)
and LL2019 (Lavoué et al., 2021). The inversion includes a three-layered crust where seismic
velocities and densities are lithologically linked through correlations from global petrophysical
data sets, and a lithospheric mantle layer defined both thermally and chemically. Mantle seismic
velocities and densities are computed as a function of the in-situ temperature and compositional
conditions using a self-consistent thermodynamic formalism. Our lithospheric models constrain
the thermal lithospheric structure of North America including shallow crust temperature and
subsurface temperature gradient maps of interest for geothermal energy studies.