[1] A combined geophysical-petrological methodology to study the thermal, compositional, density, and seismological structure of lithospheric/sublithospheric domains is presented. A new finite-element code (LitMod) is used to produce 2-D forward models from the surface to the 410-km discontinuity. The code combines data from petrology, mineral physics, and geophysical observables within a self-consistent framework. The final result is a lithospheric/sublithospheric model that simultaneously fits all geophysical observables and consequently reduces the uncertainties associated with the modeling of these observables alone or in pairs, as is commonly done. The method is illustrated by applying it to both oceanic and continental domains. We show that anelastic attenuation and uncertainties in seismic data make it unfeasible to identify compositional variations in the lithospheric mantle from seismic studies only. In the case of oceanic lithosphere, plates with thermal thicknesses of 105 ± 5 km satisfy geophysical and petrological constraints. We find that Vp are more sensitive to phase transitions than Vs, particularly in the case of the spinel-garnet transition. A low-velocity zone with absolute velocities and gradients comparable to those observed below ocean basins is an invariable output of our oceanic models, even when no melt effects are included. In the case of the Archean subcontinental lithospheric mantle, we show that ''typical'' depleted compositions (and their spatial distribution) previously thought to be representative of these mantle sections are compatible neither with geophysical nor with petrological data. A cratonic keel model consisting of (1) strongly depleted material (i.e., dunitic/harzburgitic) in the first 100-160 km depth and (2) less depleted (approximately isopycnic) lower section extending down to 220-300 km depth is necessary to satisfy elevation, geoid, SHF, seismic velocities, and petrological constraints. This highly depleted (viscous) upper layer, and its chemical isolation, may play a key role in the longevity and stability of cratons.

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We discuss the implications of a lithospheric model of the Moroccan Atlas Mountains based on topography, heat flow, gravity and geoid anomalies, taking into account the regional geology. The NW African cratonic lithosphere, some 160-180 km thick, thins to c. 80 km beneath the Atlas fold-thrust belts, in contrast with the shortening regime prevailing there since the early Cenozoic. This fact explains several geological and geophysical features as high topography with modest tectonic shortening, the occurrence of alkaline magmatism contemporaneous to compression, the absence of large crustal roots to support elevation, the scarce development of foreland basins, and a marked geoid high. The modelled lithosphere thinning is related to a thermal upwelling constrained between the Iberia-Africa convergent plate boundary and the Saharan craton.

We present a two‐dimensional lithospheric thermal and density model along a transect running from the southwestern Iberian Peninsula to the northwestern Sahara. The main goal is to investigate the lithosphere structure underneath the Gulf of Cadiz and the Atlas Mountains. The model is based on the assumption of topography in local isostatic equilibrium and is constrained by surface heat flow, gravity anomalies, geoid, and topography data. The crustal structure has been constrained by seismic and geological data where available. Mantle density is supposed to vary linearly with temperature, providing the link between thermal and density‐related data. The lithospheric thickness varies strongly along the profile, going from near 100 km under the Iberian Peninsula to at least 160–190 km under the Gulf of Cadiz and the Gharb foreland basin in Morocco and to 70 km underneath the Atlas Mountains, coinciding with a region of Neogene volcanism. The thickening of the lithosphere is interpreted as a SW trending lithospheric slab extending from the western Betics to the Gulf of Cadiz and the Gharb Basin, whereas the thin lithosphere underneath the Atlas may be interpreted as plume‐like asthenospheric upwelling similar to those observed in the west European Alpine foreland or as a side effect of a slab penetrating the less viscous asthenosphere.