Author(s): Solá, A. Rita ; Chichorro, Martim ; Cachapuz, P. ; Santos, Telmo M. Bento Dos
Date: 2023
Persistent ID: http://hdl.handle.net/10400.9/4082
Origin: Repositório do LNEG
Subject(s): Ossa-Morena Zone; Magmatism; Rifting; Galiza-Trás-os-Montes Zone; Zona de Ossa-Morena; Magmatismo; Zona de Galiza-Trás-os-Montes
SUMMARY: We present new U-Pb zircon data from the Évora Massif (SW Ossa–Morena Zone). Série Negra paragneiss of Escoural Fm. yields a maximum depositional age of ~580 Ma. Felsic orthogneiss “leptinites” included in Escoural Fm., commonly attributed to the Precambrian, yield a concordant age of 513 ± 3 Ma. Felsic volcanics interbedded in the Monfurado Fm. and the Safira Orthogneiss show very discordant zircon ages and two systematic populations at ~510 Ma and ~460 Ma. Given the stratigraphic constraint of Monfurado Fm., both magmatic rocks are considered coeval and emplaced at ~510 Ma during the main rift-related magmatism. The ~460 Ma age is not fully understood yet. Given the differences in the ages of magmatism in the Évora Massif, recently correlated with the Lower Allochthon of Galiza-Trás-os-Montes Zone, where only late rift-related magmatism is recorded, we suggest that they represent different sedimentary basins positioned in the same paleogeographic contexts.
