CORRELATION BETWEEN SEISMIC ANISOTROPY AND MAJOR GEOLOGICAL STRUCTURES IN SW IBERIA - A CASE-STUDY ON CONTINENTAL LITHOSPHERE DEFORMATION

In this paper we postulate a correlation between the lithospheric stru cture and seismic anisotropy inferred from geophysical data and the ma jor 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-Mesoz oic times in this area. However, the deviations and areal variations o bserved between the azimuthal anisotropy of seismic waves and the stru ctural trends of the accessible crust indicate that the tectonic model of orogen-parallel lithospheric deformation does not appear to succee d in relating Hercynian surface geology and the structural geology of the subcontinental lithospheric mantle. The model of polyorogenic lith osphere deformation proposed accounts for this divergence and is suppo rted from additional perspectives including the manifestation of therm al effects induced in the crust by lithospheric mantle shear zones, th e incidence of crust-mantle coupling and/or decoupling, and the scales of subcrustal heterogeneity.