Variscan Inheritance Induces Alpine Upper Crustal Delamination in East Spanish?Portuguese Central System

The Spanish-Portuguese Central System (SPCS) is an Alpine Mountain range with crystalline basement characterized by a two-layer rheological structure. This structure formed after primary (protolith) and secondary (tectonometamorphic) processes during the extensional collapse of Variscan Orogen. SPCS usually controlled foreland-directed thrusts strike-slip faults. However, eastern dominated NW-directed, imbricate backthrusts lacks main thrust directed to foreland basin located southeast mountain (Madrid Cenozoic Basin). exhibits crustal root (>40 km depth) supporting SE-directed crustal-scale thrusting. sole into SE-dipping décollement within basement. extension-related structures parallel geometry backthrusts, so they provided favorably oriented weaknesses accommodate shortening. Backthrusts geometry, their hanging wall position fault that raised gravity modeling support delamination process. Tectonic wedging more competent occurred in footwall faults (Daurius domain), which enforced shearing off rheologically weaker upper layer crust, (Arriaca domain) inverting led NW-directed incipient continental subduction crust. Intraplate can be independent from lithosphere-scale inheritance conditioned structural overlying shortening for Cretaceous cover around 17.7 (10.5% shortening), 11 (7%) upper-lower crust limit.