Amphibolite facies metamorphic event within the Upper Sebtides tectonic units (Internal Rif, Morocco): a record of a hyperextended margin at the border of the western Tethys
| Autor: | Jean-Marc Lardeaux, Ahmed Chalouan, Michel Corsini, Philippe Münch, Asmae El Bakili, Sylvain Gallet |
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| Přispěvatelé: | Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Faculté des sciences [Rabat], Université Mohammed V de Rabat [Agdal], Université Mohammed V de Rabat [Agdal] (UM5) |
| Rok vydání: | 2021 |
| Předmět: |
010504 meteorology & atmospheric sciences
Greenschist Metamorphic rock [SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography Geochemistry Metamorphism Upper Triassic metamorphism engineering.material 010502 geochemistry & geophysics 01 natural sciences Continental margin Tethys Metamorphic facies 0105 earth and related environmental sciences General Environmental Science [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics Peridotite Rif Basement (geology) engineering General Earth and Planetary Sciences Geology Biotite Gibraltar Arc 40Ar–39Ar dating [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy |
| Zdroj: | Comptes Rendus Géoscience Comptes Rendus Géoscience, Elsevier, 2021, 353 (1), pp.193-208. ⟨10.5802/crgeos.59⟩ Comptes Rendus Géoscience, 2021, 353 (1), pp.193-208. ⟨10.5802/crgeos.59⟩ |
| ISSN: | 1778-7025 |
| DOI: | 10.5802/crgeos.59 |
| Popis: | International audience; the Alpine belt that exhibits peridotite massifs associated with high-grade crustal metamorphic units. The timing and mechanisms of exhumation of these crust–mantle associations are still debated in the Rif in Morocco as well as in the Betic Cordilleras in Spain. A structural, petrographic, and geochronological study (40Ar–39Ar method) is performed in the Beni Bousera region (Internal Rif) on the Upper Sebtides units that consist of Paleozoic basement and Permo-Triassic metasedimentary rocks. We point out that, in the metagreywackes, an early assemblage of K-feldspar, plagioclase, quartz, muscovite, biotite, and garnet, which is diagnostic of amphibolite facies metamorphism. By dating white mica porphyroclasts from this metamorphic assemblage, we provide the first evidence of internal Rif metamorphism of Triassic age. We assume that these crustal units belong to the ancient continental margin of the Western Tethys, and thus, we interpret this metamorphic event in the framework of a hyperextended margin that is coeval with the exhumation of the subcontinental mantle during the Upper Triassic. Afterward, these units underwent greenschist facies metamorphism during the Lower Miocene due to a thermal event related to the back-arc opening of the Alboran Basin. |
| Databáze: | OpenAIRE |
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