Correlation between seismic anisotropy and major geological structures in SW Iberia: A case study on continental lithosphere deformation

Abstract

In this paper we postulate a correlation between the lithospheric structure and seismic anisotropy inferred from geophysical data and the major structures and tectonic history (past tectonothermal features) of the outcropping basement rocks in SW Iberia. Oblique plate convergence, orogenesis, and terrane accretion have been documented for pre‐Mesozoic times in this area. However, the deviations and areal variations observed between the azimuthal anisotropy of seismic waves and the structural trends of the accessible crust indicate that the tectonic model of orogen‐parallel lithospheric deformation does not appear to succeed in relating Hercynian surface geology and the structural geology of the subcontinental lithospheric mantle. The model of polyorogenic lithosphere deformation proposed accounts for this divergence and is supported from additional perspectives including the manifestation of thermal effects induced in the crust by lithospheric mantle shear zones, the incidence of crust‐mantle coupling and/or decoupling, and the scales of subcrustal heterogeneity.