Isotopic (Sr-Nd) signatures of the Pedregal Granite and associated migmatite rocks [Características isotópicas (Sr-Nd) do Granito do Pedregal e rochas migmatíticas associadas]

• Type: Article in International Scientific Journal
• Date: 2015

Authors

Ferreira, JA (Author) Other; H. C. B. Martins (Author) FCUP; Santos, JF (Author) Other; Anjos Ribeiro (Author) FCUP

Journal

Title: Comunicações Geológicas

Vol. 102

Pages: 147-151

ISSN: 0873-948X

Publisher: LNEG - Laboratório Nacional de Energia e Geologia

Indexing

Scopus - 2 Citations

Scientific classification

FOS: Natural sciences

Other information

Authenticus ID: P-00N-2PA

Abstract (EN): The synorogenic Variscan granite-migmatite complex in study outcrops in the Central Iberian Zone, northern Portugal. The Pedregal granite dated of 311±5 Ma has an NW-SE elongated shape and is intrusive in staurolite-micaschist and banded gneiss-migmatite rocks, with local igneous breccias along the contact. This granite is a fine to medium-grained two mica rock with small biotitic nodules (1 to 2 cm). The associated gneiss-migmatite rocks of stromatic metatexitic character are banded, showing alternating of quartz-feldspathic leucosomes without foliation and subordinated micaceous paleosomes disclosing garnet - quartz intergrowths (< 1 cm). The Sr-Nd isotopic results for the Pedregal granite and associated gneiss-migmatite rocks indicate quite different compositions, in apparent contradiction with geochemical data previously presented. Their isotopic heterogeneity could be explained by Nd isotopic disequilibrium developed both during the melting event and late muscovitization, with Rb/Sr enrichment in the granite. © 2015 LNEG - Laboratório Nacional de Geologia e Energia IP.

Language: Portuguese

Type (Professor's evaluation): Scientific