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Age constraints on Lower Paleozoic convection system: Magmatic events in the NW Iberian Gondwana margin

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Díez Fernández, Rubén and Castiñeiras García, Pedro and Gómez Barreiro, Juan (2012) Age constraints on Lower Paleozoic convection system: Magmatic events in the NW Iberian Gondwana margin. Gondwana research, 21 . pp. 1066-1079. ISSN 1342-937X

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Official URL: http://www.journals.elsevier.com/gondwana-research/



Abstract

The basal units of the allochthonous complexes of NW Iberia are used to examine the Lower Paleozoic geodynamic evolution of the northern Gondwana margin. These units represent the most external continental margin and the sequence of major magmatic events that affected them has been dated. Isotopic dating and field data highlight the existence of two magmatic pulses, dated at 489±4 Ma (granodiorites) and 474±3 Ma (alkali-granites), and a slightly younger alkaline/peralkaline pulse, dated at ca. 470–475 Ma (alkaline and peralkaline granites). Their framing into the regional background has allowed us to explore the major lithosphere-scale processes developed at the Gondwana periphery at that time, as well as to conceive a consistent model for the opening of the Rheic Ocean that reconciles the timing of sea opening and back-arc extension with the timing of intracontinental rifting. The sequence of events is framed in a Cambrian and Ordovician peri-Gondwanan subduction setting where we also explore how subduction may be linked to
coeval intraplate magmatism far inboard of the arc–trench. This contribution discusses how such a scenario can be traced in basement areas through a modern analog perspective.


Item Type:Article
Uncontrolled Keywords:Convection, Mantle dynamics, Plume, Gondwana, NW Iberia
Subjects:Sciences > Geology > Petrology
Sciences > Geology > Geodynamics
ID Code:23143
Deposited On:14 Oct 2013 07:46
Last Modified:14 Oct 2013 07:46

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