Early variscan HP metamorphism in the western Iberian Allochthon - A 390 Ma U-Pb age for the Braganca eclogite (NW portugal) | Health & Environmental Research Online (HERO)

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Citation
Tags

HERO ID

515545

Reference Type

Journal Article

Title

Early variscan HP metamorphism in the western Iberian Allochthon - A 390 Ma U-Pb age for the Braganca eclogite (NW portugal)

Author(s)

Roger, F; Matte, P

Year

2005

Is Peer Reviewed?

Yes

Journal

International Journal of Earth Sciences
ISSN: 1437-3254
EISSN: 1437-3262

Volume

Issue

Page Numbers

173-179

Language

English

DOI

10.1007/s00531-005-0466-3

Abstract

HP rocks ( eclogites and granulites) occur in the upper unit of the western Iberian allochthonous complexes in Spain and Portugal. This HP metamorphism was considered as Early Variscan or Ordovician in Spain and Precambrian in Portugal. We have dated eclogites retrogressed into granulites in the Braganca massif in NE Portugal by U - Pb on rutile and zircon. The upper intercept of the discordia gives 390 +/- 4 Ma that we consider as the age of the HP/HT metamorphism.

Keywords

Braganca complex; Upper Allochthon unit; HP metamorphic rock; U-Pb; dating; Devonian; cabo-ortegal complex; northwestern spain; nd isotope; evolution; zircon; ordovician; petrology; example; galicia; massif