Please use this identifier to cite or link to this item: http://hdl.handle.net/1822/3526

TitleU–Pb zircon and monazite geochronology of post-collisional hercynian granitoids from the Central Iberian Zone (Northern Portugal)
Author(s)Dias, G.
Leterrier, J.
Mendes, Anabela Carreira
Simões, P. P.
Bertrand, J. M.
KeywordsIberian Peninsula
Hercynian
Granitoids
Zircon
Monazite
U–Pb geochronology
Issue dateDec-1998
PublisherElsevier
JournalLithos
Citation"Lithos". ISSN 0024-4937. 45 (1998) 349–369.
Abstract(s)In the Central Iberian Zone (CIZ) of the Iberian Massif large volumes of granitoids were emplaced during the post-collisional stage of the Hercynian orogeny (syn- to post-D3, the last ductile deformation phase). Twelve granitic units and a quartz monzodiorite were selected for a U–Pb zircon and monazite geochronological study. They represent successive stages of the D3 event. The Ucanha-Vilar, Lamego, Sameiro and Refoios do Lima plutons are coeval (313±2 Ma, 319±4 Ma, 316±2 Ma and 314±2 Ma, respectively) and belong to the earliest stage. Later on the Braga massif was emplaced, its different units yielding the same age: 309±3 Ma for the Braga granite, 309±1 Ma for the Gonça granite and 311±5 Ma for a related quartz monzodiorite. The Braga massif is subcontemporaneous with the Agrela and Celeirós plutons (307±3.5 Ma and 306±2 Ma, respectively), in agreement with field data. The Briteiros granite is younger (300±1 Ma), followed by the emplacement of the Peneda–Gerês massif (Gerês, Paufito, Illa and Carris granites). The Gerês granite, emplaced at 296±2 Ma, seems to represent a first magmatic pulse immediately followed by the intrusion of the Paufito granite at 290±2.5 Ma. For the Carris granite a minimum emplacement age of 280±5 Ma was obtained. Based on these results the following chronology is proposed: (1) syn-D3 biotite granitoids, 313–319 Ma; (2) late-D3 biotite-dominant granitoids, 306–311 Ma; (3) late- to post-D3 granitoids, ca. 300 Ma; (4) post-D3 granitoids, 290–296 Ma. These chronological data indicate that successive granitic intrusions were emplaced in the CIZ during a short time span of about 30 Ma that corresponds to the latest stages of the Hercynian orogeny. A rapid and drastic change occurred at about 300 Ma, between a compressive ductile tectonic regime (D3, ca. 300–320 Ma) associated to calc-alkaline, monzonitic and aluminopotassic plutonism and a fragile phase of deformation (D4) which controlled the emplacement of the subalkaline ferro-potassic plutonism at 290–296 Ma.
TypeArticle
URIhttp://hdl.handle.net/1822/3526
DOI10.1016/S0024-4937(98)00039-5
ISSN0024-4937
Publisher versionhttp://www.sciencedirect.com/science/article/pii/S0024493798000395
Peer-Reviewedyes
AccessOpen access
Appears in Collections:CCT - Artigos (Papers)/Papers

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