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Articles dans des revues avec comité de lecture |
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| domaine : |
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| titre : |
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Triassic alkaline magmatism of the Hawasina Nappes: Post-breakup melting of the Oman lithospheric mantle modified by the Permian Neotethyan Plume |
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| auteur(s) : |
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François Chauvet ( ) 1, 2, Henriette Lapierre 2, René C. Maury 3, Delphine Bosch () 4, Christophe Basile () 2, Joseph Cotten 3, Pierre Brunet 5, Sylvain Campillo 2 |
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| Équipe de recherche : |
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Tectonique reliefs et bassins |
| résumé : |
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Middle to Late Triassic lavas were sampled within three tectonostratigraphic groups of the Hawasina Nappes in the Oman Mountains. They are predominantly alkali basalts and trachybasalts, associated with minor sub-alkaline basalts, trachyandesites, trachytes and rhyolites. Their major, trace elements and Nd-Pb isotopic compositions are very similar to those of the Permian plume-related high-Ti basalts which also occur in the Hawasina Nappes. The Triassic lavas derive from low-degree melting of an enriched OIB-type mantle source, characterized by εNdi = 0.3-5.3 and (206Pb/204Pb)i = 16.96-19.31 (for t = 230 My). With time, melting depths decreased from the garnet + spinel to the spinel lherzolite facies and the degree of melting increased. The oldest are distinguished from the others by unradiogenic Nd and Pb signatures, with εNdi = − 4.5 to − 1.2 and (206Pb/204Pb)i = 16.35-17.08, which we attribute to their contamination by Arabo-Nubian lower crust. The lavas likely derived from the Oman lithospheric mantle, the original DMM-HIMU signature of which was overprinted during its pervasive metasomatism by the Permian plume-related melts. We suggest that these lavas were emplaced during post-breakup decompression-triggered melting in the Middle Triassic during global kinematic reorganization of the Tethyan realm. |
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langue du texte
intégral : |
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Anglais |
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| journal : |
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| Lithos |
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Elsevier |
| ISSN |
0024-4937 |
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internationale |
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| date de publication : |
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02/2011 |
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| volume : |
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122 |
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1-2 |
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| page, identifiant, ... : |
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pp.122-136 |
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| mots-clés : |
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Neotethys – Passive margin – Post-breakup magmatism – Triassic – Hawasina – Oman Mountains |
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| contrat, financement : |
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Funded by the Institut National des Sciences de la Terre, programme "Intérieur de la Terre", the Groupement de Recherche "Marges", CNRS UMR 5025 (Université Joseph Fourier, Grenoble) and UMR 6538 (Université de Bretagne Occidentale, Brest), and the BRGM Research Division. |
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