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Rheic Ocean ophiolitic remnants in southern Iberia questioned by SHRIMP U-Pb zircon ages on the Beja-Acebuches amphibolites

Azor, A; Rubatto, Daniela; Simancas, J F; Gonzalez-Lodeiro, F; Martınez Poyatos, D; Martin Parra, L.M.; Matas, J.

Description

The Rheic Ocean was a major oceanic domain between Avalonia and Gondwana in Ordovician-Silurian times. Most of the Paleozoic plate reconstructions assume that the Rheic Ocean suture lies within southern Iberia, coinciding with the contact between the South Portuguese Zone and the Ossa-Morena Zone. This paper reports four Sensitive High Resolution Ion Micro-Probe (SHRIMP) U-Pb zircon ages from mid-ocean ridge basalt (MORB)-featured rocks of the Beja-Acebuches Amphibolite unit, which crops out...[Show more]

dc.contributor.authorAzor, A
dc.contributor.authorRubatto, Daniela
dc.contributor.authorSimancas, J F
dc.contributor.authorGonzalez-Lodeiro, F
dc.contributor.authorMartınez Poyatos, D
dc.contributor.authorMartin Parra, L.M.
dc.contributor.authorMatas, J.
dc.date.accessioned2015-12-08T22:23:09Z
dc.identifier.issn0278-7407
dc.identifier.urihttp://hdl.handle.net/1885/32743
dc.description.abstractThe Rheic Ocean was a major oceanic domain between Avalonia and Gondwana in Ordovician-Silurian times. Most of the Paleozoic plate reconstructions assume that the Rheic Ocean suture lies within southern Iberia, coinciding with the contact between the South Portuguese Zone and the Ossa-Morena Zone. This paper reports four Sensitive High Resolution Ion Micro-Probe (SHRIMP) U-Pb zircon ages from mid-ocean ridge basalt (MORB)-featured rocks of the Beja-Acebuches Amphibolite unit, which crops out along the boundary between the Ossa-Morena and the South Portuguese Zone, and is considered its most conspicuous suture unit. The obtained ages range from 332 ± 3 to 340 ± 4 Ma, corresponding to the crystallization of the mafic protoliths. These Early Carboniferous ages for the Beja-Acebuches aniphibolites imply that this unit can no longer be viewed as an ophiolite belonging to the Rheic Ocean suture, since this oceanic domain was presumably closed in Devonian times. Tectonic reconstructions joining in a single suture line the Beja-Acebuches Amphibolite unit in southern Iberia to either the Devonian Lizard ophiolite in southern England or the root zone of the Devonian/Ordovician ophiolitic units in northwest Iberia must be therefore reconsidered because of the age difference. We interpret the Beja-Acebuches Amphibolite unit to represent a narrow and very ephemeral realm of oceanic-like crust that opened in Early Carboniferous times, after total consumption of the Rheic Ocean. We suggest that a mantle plume underneath southern Iberia in Early Carboniferous times is the most plausible large-scale geodynamic scenario for the formation of these MORB-featured rocks.
dc.publisherAmerican Geophysical Union
dc.sourceTectonics
dc.subjectKeywords: amphibolite; Avalonia; geodynamics; Gondwana; mantle plume; mid-ocean ridge basalt; oceanic crust; ophiolite; Ordovician; protolith; SHRIMP dating; Silurian; suture zone; tectonic reconstruction; uranium-lead dating; England; Eurasia; Europe; Iberian Peni
dc.titleRheic Ocean ophiolitic remnants in southern Iberia questioned by SHRIMP U-Pb zircon ages on the Beja-Acebuches amphibolites
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume27
dc.date.issued2008
local.identifier.absfor040303 - Geochronology
local.identifier.absfor040313 - Tectonics
local.identifier.ariespublicationu4047674xPUB95
local.type.statusPublished Version
local.contributor.affiliationAzor, A, Universidad de Granada
local.contributor.affiliationRubatto, Daniela, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationSimancas, J F, Universidad de Granada
local.contributor.affiliationGonzalez-Lodeiro, F, Universidad de Granada
local.contributor.affiliationMartınez Poyatos, D, Universidad de Granada
local.contributor.affiliationMartin Parra, L.M., Instituto Geologico y Minero de Espana, Madrid, Spain
local.contributor.affiliationMatas, J., Instituto Geologico y Minero de Espana, Madrid, Spain
local.description.embargo2037-12-31
local.bibliographicCitation.startpageTC5006
local.identifier.doi10.1029/2008TC002306
dc.date.updated2016-02-24T10:32:41Z
local.identifier.scopusID2-s2.0-58149495298
local.identifier.thomsonID000259806700002
CollectionsANU Research Publications

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