Petrogenetic constraints on the felsic vein magmatism in northern Portugal based on petrological and geochemical data

• Tipo: Artigo em Revista Científica Internacional
• Data: 2021

Autores

Oliveira, AJT (Autor) Outra; H. C. B. Martins (Autor) FCUP; Sant'Ovaia, H (Autor) FCUP

Revista

Título: Comptes Rendus - Geoscience

Vol. 353

Páginas: 377-398

ISSN: 1631-0713

Editora: Academie des Sciences

Indexação

ISI Web of Knowledge - 0 Citações

Scopus - 1 Citação

Outras Informações

ID Authenticus: P-00V-Z3W

DOI: 10.5802/crgeos.100

Abstract (EN): Three of the largest granite porphyries of northern Portugal were studied to improve current knowledge on the regional felsic vein hypabyssal magmatism. All porphyries exhibit microcrystalline groundmasses of variable granularity (composed of quartz, K-feldspar, and muscovite), quartz, K-feldspar, plagioclase, biotite, and cordierite phenocrysts, antirapakivi and rapakivi feldspars, embayments in quartz, and enrichments in rare metal incompatible elements. The veins were emplaced along fractures generated during the last phase of the Variscan orogeny. Textural features were presumably conditioned by fast cooling, volatile loss, subsolidus annealing, and the magnitude of thermal contrasts at the time of emplacement. All veins were altered by subsolidus hydrothermal fluids, as suggested by several petrographic and geochemical evidence. The generation of mantled feldspars is probably related to isothermal decompression and magma mixing, which is compatible with the epsilon Nd-i signatures (-3.76 to -4.40). Based on this research, both processes have contributed to the petrogenesis of the studied porphyries.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 23