%0 Journal Article
%A Rubio Pascual, Francisco J.
%A Arenas Martín, Ricardo
%A Martínez Catalán, José Ramón
%A Rodríguez Fernández, Luis Roberto
%A Wijbrans, Jan R.
%T Thickening and exhumation of the Variscan roots in the Iberian Central System:Tectonothermal processes and 40Ar/39Ar ages
%D 2013
%@ 0040-1951
%U https://hdl.handle.net/20.500.14352/44352
%X 40Ar/39Ar dating of white mica inmetapelites, thermobarometric calculations and new structural and geologicalmapping have been carried out in the Somosierra region (Iberian Central System, ICS) to investigate the Variscanthickening–exhumation processes and the evolution of the paleo-thermal structure in a key region of the CentralIberian Zone. The rocks underwent an intermediate P/T event (M1) during a D1 stage of crustal thickening initiatedbetween 354 and 347 Ma. This eventwas probably related to a first S to SE-directed emplacement of theNWIberian allochthon, and during the initial development of amid-crustal subhorizontal shear zone accommodatingthe ductile flow of thermally weakened crust parallel to the main orogenic trend. Syn-convergent extension ofthe upper levels occurred by 335–327 Ma, when tectonic unroofing led to D2 domal uplift of the orogenicroots and to recrystallization of rocks under intermediate to low P/T conditions (M2). Individualized gneissdomes developed along the orogenic trend, whereas some post-M2 thrusts dated at c. 319 Ma reflect lateralflow related to limited gravitational spreading of the domes. Younger upright to SW verging folding of the ICSdome during D3 progressive renewal of contractive deformation took place after 316 Ma. Final D4 gravitationalcollapse occurred under low P/T conditions (M3) at c. 300 Ma, accompanied by the intrusion of large volumes ofanatectic granitoids.
%~