Ediacaran–Palaeozoic tectonic evolution of the Ossa Morena and Central Iberian zones (SW Iberia) as revealed by Sm–Nd isotope systematics
Sm–Nd isotopic analyses of Palaeozoic sedimentary and igneous rocks in the southwest Iberian Massif (western end of the European Variscan Belt) are presented in order to unravel its complex poly-orogenic evolution during the closure of the Rheic Ocean and the amalgamation of Pangea. The Gondwanan ma...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2008 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/52403 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/52403 |
| Access Level: | acceso abierto |
| Palabra clave: | 551.24(234.1) Tectonic evolution Ossa Morena Zone Central Iberian Zone Nd isotopes Geodinámica Geoquímica 2507 Geofísica 2503 Geoquímica |
| Sumario: | Sm–Nd isotopic analyses of Palaeozoic sedimentary and igneous rocks in the southwest Iberian Massif (western end of the European Variscan Belt) are presented in order to unravel its complex poly-orogenic evolution during the closure of the Rheic Ocean and the amalgamation of Pangea. The Gondwanan margin in southwest Iberia SW Iberia is subdivided into the Ossa Morena and Central Iberian zones, separated by the Badajoz–Córdoba Shear Zone which represents a cryptic suture zone between these terranes. The relationships between these terranes, and between units preserved within the suture zone (e.g. the Sierra Albarrana Group) during the Palaeozoic and Neoproterozoic are controversial. Sm–Nd isotopic studies of representative sedimentary sequences covering the entire pre-Variscan record of the Ossa Morena and Central Iberian zones show very similar characteristics from the uppermost Ediacaran onwards. These data indicate that their accretion to one another must have been completed by the Late Neoproterozoic–Ediacarin that time (an event assigned to Cadomian orogeny) and that they never separated substantially from each other since that time. The Sm–Nd isotopic composition of the Sierra Albarrana Group metasedimentary rocks is similar to that of the pre-Cadomian sequences of the Ossa Morena Zone (Serie Negra), suggesting derivation from a common source. The common provenance of the Palaeozoic sequences in the two zones is identical to that of the pre-Cadomian Serie Negra of the Ossa Morena Zone, which in accordance with the data presented herein and published U–Pb zircon data indicates a West African affinity. |
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