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Tracing the Cambro-Ordovician ferrosilicic to calc-alkaline magmatic
Diaz-Alvarado, Juan; Fernandez, Carlos; Chichorro, Martim; Castro, Antonio; Pereira, M FranciscoU–Pb geochronological study of zircons from nodular granites and Qtz-diorites comprising part of Variscan high- grade metamorphic complexes in Gredos massif (Spanish Central System batholith) points out the significant presence of Cambro-Ordovician protoliths among the Variscan migmatitic rocks that host the Late Carboniferous intrusive granitoids. Indeed, the studied zone was affected by two contrasted tectono...
Extensional orogenic collapse captured by strike-slip tectonics:
Diez Fernandez, Ruben; Pereira, M FranciscoThe late Paleozoic collision between Gondwana and Laurussia resulted in the polyphase deformation and magmatism that characterizes the Iberian Massif of the Variscan orogen. In the Central Iberian Zone, initial con- tinental thickening (D1; folding and thrusting) was followed by extensional orogenic collapse (D2) responsible for the exhumation of high-grade rocks coeval to the emplacement of granitoids. This st...
Early Carboniferous synorogenic basins evolution of the Ossa-Morena and
Pereira, M Francisco; Dias da Silva, Icaro F; Gama, Cristina; Castro, Antonio; Fernandez, CarlosThe stratigraphic record of the Early Carboniferous in Iberia reveals that synorogenic deposition was important and occurred simultaneously in basins influenced by extension and contraction with gravitational instability. In NW Iberia (Galicia – Trás-os-Montes Zone) contraction was dominant and the deposition took place in a forebulge outwards from the nappe stacking front. Here, synorogenic deposits were stron...
Superposition relations of microfabrics in the northern hanging-wall block
Dias da Silva, Icaro F; Pereira, M Francisco; Silva, Jose BThis study reports alternation of D2 extension-related and D3 contraction-related microfabrics in the northern hanging wall block of a gneiss dome-like structure recognized in the Évora Massif (Ossa-Morena Zone). In the Arraiolos – Santo Antonio de Alcorrego traverse high- to low-grade mylonites are dominant. Microfabrics related to D2 ductile deformation and M2 high-amphibolite to greenschist facies characteri...
The role of strain localization in magma injection into a transtensional shear ...
Pereira, M Francisco; Chichorro, M; Fernández, C; Silva, JB; Matias, FThis study deals with the interaction between deformation and magmatism in mid- to deep-crustal domains. The relation is analysed between migmatites and shear zones and the spatial distribution of leucogranitoid veins and dykes running through a footwall migmatite system, and reaching a transtensional shear zone operated under amphibolite- to greenschist-facies metamorphic conditions (Boa Fé shear zone, Varisca...
Variability over time in the sources of South Portuguese Zone turbidites: evide...
Pereira, M Francisco; Ribeiro, C; Vilallonga, F; Chichorro, M; Drost, K; Albardeiro, L; Hofmann, M; Linnemann, UThis study combines geochemical and geo- chronological data in order to decipher the provenance of Carboniferous turbidites from the South Portuguese Zone (SW Iberia). Major and trace elements of 25 samples of graywackes and mudstones from the Me´rtola (Visean), Mira (Serpukhovian), and Brejeira (Moscovian) Forma- tions were analyzed, and 363 U-Pb ages were obtained on detrital zircons from five samples of gray...
Early Cambrian granitoids of North Gondwana margin in the transition from a con...
Sanchez-Garcia, T; Pereira, M Francisco; Bellido, F; Chichorro, M; Silva, JB; Valverde-Vaquero, P; Pin, Ch; Sola, ARTwo distinct Cambrian magmatic pulses are recognized in the Ossa-Morena Zone (SW Iberia): an early rift-(ER) and a main rift-related event. This Cambrian magmatism is related to intra-continental rifting of North Gondwana that is thought to have culminated in the opening of the Rheic Ocean in Lower Ordovician times. New data of whole-rock geochemistry (19 samples), Sm– Nd–Sr isotopes (4 samples) and ID–TIMS U–P...
Permo-Carboniferous magmatism in the core of Pangaea (Southern Pyreness): a pos...
Pereira, M Francisco; Castro, A.; Chichorro, M.; Fernandez, C.; Diaz-Alvarado, J.; Marti, J.; Rodriguez, C.In southern Europe and the western Mediterranean, Permo-Carboniferous magmatism is well represented in areas of Iberia, the Alps, Sardinia and the Balkan Peninsula. In Iberia, the magmatism that has been related to the Variscan orogeny is associated with syn-orogenic events at ca. 350-315 Ma and post-orogenic at ca. 310-295 Ma. In the southern Pyrenees there is Permo-Carboniferous sedimentary basins with a sign...