Autor(es): Roseiro, José ; Moreira, Noel ; Nogueira, Pedro ; de Oliveira, Daniel Pipa Soares
Data: 2023
Identificador Persistente: http://hdl.handle.net/10400.9/4098
Origem: Repositório do LNEG
Assunto(s): Faixa Blastomilonítica; Ortognaisses Alcalinos; Ortognaisses Hiperalcalinos; Deformação; Zona de Ossa-Morena; Blastomylonitic Belt; Alkaline Orthogneisses; Peralkaline Orthogneisses; Deformation; Ossa-Morena Zone
SUMMARY: In the Blastomylonitic Belt (northernmost Ossa-Morena Zone), alkaline and peralkaline orthogneisses are found as elongated bodies with WNW-ESE to NW-SE orientation hosted within a strongly deformed Neoproterozoic to Lower Cambrian metasedimentary strata. Despite some similarities between them (ascribed to the very similar nature of their igneous protolith) the deformational features displayed in all of them are different, for example in the mineral segregation and recrystallization (including the development of augens) observed, and in different strike-dip orientation of foliations and lineation plunge. The dissimilarities are presumably due not only from different primary features, but also to the type of ductile shearing and metamorphic conditions they underwent. This way, field data will be complemented with petrographic studies for mineralogical and microdeformation characterization, and crossed to the regional structural information, thus constraining the deformation patterns of the alkaline-peralkaline orthogneisses on the Blastomylonitic Belt.
