North-Gondwana assembly, break-up and paleogeography: U–Pb isotope evidence from detrital and igneous zircons of Ediacaran and Cambrian rocks of SW Iberia

• Published in: Gondwana research Vol. 22; no. 3-4; pp. 866 - 881
• Main Authors: Pereira, M.F., Solá, A.R., Chichorro, M., Lopes, L., Gerdes, A., Silva, J.B.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2012
• Subjects: Cambrian ensialic basins; LA-ICPMS; Neoproterozoic back-arc basins; Pan-African and Cadomian orogenies; Zircon geochronology; LA-ICPMS; Cambrian ensialic basins; Neoproterozoic back-arc basins; Pan-African and Cadomian orogenies; Zircon geochronology
• ISSN: 1342-937X; 1878-0571
• DOI: 10.1016/j.gr.2012.02.010

The Estremoz Anticline in the Ossa-Morena Zone (SW Iberia) includes upper Ediacaran detrital rocks unconformably overlain by lower Cambrian detrital and carbonate rocks. The spectra of detrital zircon U–Pb ages dominated by Cryogenian and Ediacaran ages (with a typical gap in Mesoproterozoic ages) of the upper Ediacaran greywackes and lower Cambrian arkosic sandstones indicate provenance from sources placed near or at the North-Gondwana margin. These late Ediacaran and early Cambrian basins developed in a paleoposition close to the West African Craton and related to a long-lived Neoproterozoic magmatism (c. 850–700Ma — Pan-African suture; c. 700–635Ma — early Cadomian arc; and c. 635–545Ma — late Cadomian arc). The rhyolites of the Volcanic–Sedimentary Complex of Estremoz whose stratigraphic position so far has been a controversy, yielded an upper Cambrian age (Furongian) at about 499Ma indicating that carbonate production was episodic in SW Iberia during the Cambrian. This new evidence should be taken into account in the reshaping of paleogeographic reconstruction models that have erroneously insisted on placing Iberia at southerly cold water higher latitudes (>60°S) during the Furongian. [Display omitted] ► Ediacaran–Cambrian basins of Iberia have a lof of Cryogenian and Ediacaran zircons. ► Paleoproterozoic and Archean zircons show a link of Iberia with West African craton. ► Marbles with Furongian age indicate a paleoposition for Iberia away from the poles.