Zircon U-Pb geochronology of paragneisses and biotite granites from the SW Iberian Massif (Portugal): evidence for a paleogeographic link between the Ossa-Morena Ediacaran basins and the West African craton

M. F. Pereira, Martim Afonso Ferreira de Sousa Chichorro, I. S. Williams, José Brandão Silva

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

Abstract

Sensitive high-resolution ion microprobe U–Th–Pb age determinations on detrital and inherited zircon from the E ´ vora Massif (SW Iberian Massif, Portugal) provide direct evidence for the provenance of the Ossa–Morena Ediacaran basins (Se´rie Negra) and a palaeogeographical link with the West African craton. Three samples of the Se´rie Negra paragneisses contain large components of Cryogenian and Ediacaran ( zircon of Mesoproterozoic ( ( Arraiolos biotite granite, which was formed by partial melting of the Se´rie Negra and overlying Cambrian rocks. These results are consistent with substantial denudation of a continental region that supplied sediments to the Ediacaran Ossa–Morena basins during the final stages of the Cadomian–Avalonian orogeny (peri-Gondwanan margin with principal zircon-forming events at same age from Portugal, Spain, Germany and Algeria, our data suggest that the sediment supply to the Ediacaran–Early Palaeozoic siliciclastic sequences preserved in all these peri- Gondwanan regions was similar. The lack of Grenvillian-aged ( Ossa–Morena and Saxo-Thuringia Ediacaran sediments suggests that the sediment in these peri-Gondwanan basins was derived from the West African craton.c. 700–540 Ma) detrital zircon, but have a marked lack ofc. 1.8–0.9 Ga) age. Older inherited zircons are of Palaeoproterozoicc. 2.4–1.8 Ga) and Archaean (c. 3.5–2.5 Ga) age. The same age pattern is also found in thec. 575 Ma and c. 615 Ma). Combined with the detrital zircon ages reported for rocks of thec. 1.1–0.9 Ga) zircon in the
Original languageEnglish
Title of host publicationThe Boundaries of the West African Craton
EditorsNasser Ennih, Jean-Paul Liégeois
Place of PublicationLondon
PublisherGeological Society, Special Publications
Pages385-404
Number of pages20
ISBN (Print)978-1-86239-251-9
Publication statusPublished - 2008

Publication series

NameGeological Society Special Publication
PublisherGeological Society of London
Volume297
ISSN (Print)0305-8719

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