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- Exhumation of an anatectic complex by channel flow and extrusion tectonics: structural and metamorphic evidence from the Porto–Viseu Metamorphic Belt, Central-Iberian ZonePublication . M. Bento dos Santos, Telmo; Rodrigues, José Feliciano; Castro, Paulo; Cotrim, Beatriz; Pereira, Inês; Ferreira, Joana; Pinto De Meireles, Carlos Augusto; Ferreira, Narciso; Ferreira, Priscila; Ribeiro, António; Guimarães, FernandaAbstract: Structural and metamorphic analyses of the Porto–Viseu Metamorphic Belt (PVMB), an anatectic complex located in the Central-Iberian Zone (CIZ), Iberian Variscan Massif, constrain the kinematic features of the polyphase Variscan deformation, as well as the boundary conditions associated with the exhumation and emplacement of the belt onto the CIZ’s lower-grade metasediments. A sharp metamorphic contrast is evident between the lowest grade rocks of the anatectic complex—garnet-staurolite mylonitic schists with a minimum metamorphic peak at P = 5.7 kbar and T = 635 °C—and the host chlorite-biotite metasediments of the CIZ. Additional P–T estimates for metatexites in the PVMB provided P = 7.6–7.9 kbar and T = 770–810 °C, confirming high-grade metamorphic peak conditions. The temperature jump between the anatectic complex and the low-grade host rocks exceeds 400 °C if the anatectic core of the belt (metatexites, diatexites, and S-type granites) is considered, implying a vertical difference of 10–17 km. The PVMB is limited in the NE by a D2 shear zone displaying normal kinematics, which has been explained so far by extensional tectonics. However, the SW boundary is limited by a D2 shear zone showing reverse kinematics. This pair of coeval and antithetical ductile shear zones bordering the PVMB, associated with the increase of the metamorphic grade towards the axial domain of the belt, is consistent with anatectic channel flow, followed by extrusion tectonics of the PVMB within an overall D2 compressive setting.
- Organização tectonoestratigráfica do complexo parautóctone do NE de Portugal : uma propostaPublication . Rodrigues, J.; Ribeiro, António; Pereira, Eurico; Pinto de Meireles, Carlos AugustoCom base em características geométricas e estratigráficas apresenta-se, para o NE de Portugal, uma divisão interna no Complexo Parautóctone: o Parautóctone Inferior está estruturado num conjunto interno de acidentes inversos imbricados envolvendo unidades silúrico-devónicas; o Parautóctone Superior apresenta macrogeometrias do tipo manto-dobra, com flancos inversos que podem apresentar mais de 10 km de extensão e unidades com possível idade ordovícica no núcleo de grandes anticlinais deitados e vergentes para E a SE.
- Deformação não-coaxial na Faixa Metamórfica Porto-Viseu : détachement extensional ou par thrust/underthrust contracional?Publication . Rodrigues, José Feliciano; Bento dos Santos, Telmo; Castro, Paulo Ferreira; Meireles, Carlos; Ferreira, Pedro Tavares; Ribeiro, António; Pereira, Eurico; Ferreira, Narciso