U-PB ZIRCON AND MONAZITE GEOCHRONOLOGY OF THE HERCYNIAN 2-MICA GRANITE COMPOSITE PLUTON OF CABECEIRAS-DE-BASTO (NORTHERN PORTUGAL)

Authors
ALMEIDA A LETERRIER J NORONHA F BERTRAND JM
Citation
A. Almeida et al., U-PB ZIRCON AND MONAZITE GEOCHRONOLOGY OF THE HERCYNIAN 2-MICA GRANITE COMPOSITE PLUTON OF CABECEIRAS-DE-BASTO (NORTHERN PORTUGAL), Comptes rendus de l'Academie des sciences. Serie 2. Sciences de la terre et des planetes, 326(11), 1998, pp. 779-785
Citations number
20
Categorie Soggetti
Geosciences, Interdisciplinary
Journal title
Comptes rendus de l'Academie des sciences. Serie 2. Sciences de la terre et des planetes → ACNP
ISSN journal
12518050
Volume
326
Issue
11
Year of publication
1998
Pages
779 - 785
Database
ISI
SICI code
1251-8050(1998)326:11<779:UZAMGO>2.0.ZU;2-N
Abstract
The zircon and monazite U-Pb minimum age of the Hercynian peraluminous two-mica composite granite pluton of Cabeceiras de Baste (Northern Po rtugal) is 311+/-1 Ma (2 sigma). This age, well constrained by a conco rdant monazite of 311 +/- 4 Ma (2 sigma), is in good agreement with th e age suggested for the synkynematic, syn-D3, Iberian granites of the Hercynian orogeny (315-305; Pinto et al., 1987). The (Sr-87/Sr-86)(i) and epsilon(Nd) isotopic ratios, calculated for 311 Ma, suggest that t he three granite units which constitute the massif may derive from an heterogeneous crustal source dated (upper intercept of the discordia) around 1 200 Ma. (C) Academie des sciences/Elsevier, Paris.