This study deals with the provenance of lower-middle Jurassic successions cropping out in the Prerif Foreland basin of the Rif chain (Morocco), by merging sedimentary petrology and U-Pb zircon geochronology on four stratigraphic successions to ensure a thorough new overview. The analyzed sandstone suites have been collected from the lower-Middle Jurassic sandstones of Jbel Outita, Jbel Zerhoune, and Dhar N’sour sections accumulated in different depositional paleoenvironments evolving down-slope from proximal delta to bathyal and deep-sea basin. Both lithofacies belonged to the hyper-extended margin of the NW-Gondwana during the early-middle Jurassic time coevally with the earliest rifting-drifting stages of the western edge of the Tethyan Ocean. Modal petrographic analyses show that sandstones are hybrid siliciclastic characterized by feldspathic litharenite, litharenite, and lithic arkose compositions. Detrital sandstone modes reveal a provenance from medium to high-grade metamorphic rocks namely of Transitional Continental block and recycled orogen. Reliable new U/Pb zircon data (LA-ICP-MS) from sandstone outcropping in the Prerif Basin were carried out on two samples from Jbel Zerhoune and Jbel Outita. Concordant U/Pb zircon data yielded a Paleozoic zircon age that shows provenance from the exotic Sehoul Bloc, High Atlas, and Anti-Atlas chains (Tahiri et al., 2010). Neoproterozoic cluster ages with a dominant Ediacaran zircon population at the peak (612 Ma- 598 Ma) corresponds to the Cadomian and/or the Pan-African orogens mainly of the “Sehoul block” exotic Terrane, Western Meseta, and Anti Atlas chains (El Haibi et al., 2020). Hence, rare Paleoproterozoic ages are less abundant with a peak age at 2.13 Ga, suggesting a provenance from the Anti-Atlas or probably from the Eburnean orogens of the West African Craton (WAC). (Pereira et al., 2015, Gärtner et al., 2013). EL Haibi H., EL Hadi H., Tahiri A., Martínez Poyatos D., Gasquet D., Pérez-Cáceres I., González Lodeiro F. & Mehdioui S. (2020) - Geochronology and isotopic geochemistry of Ediacaran high-K calc-alkaline felsic volcanism: An example of a Moroccan perigondwanan (Avalonian?) remnant in the El Jadida horst (Mazagonia). Journal of African Earth Sciences. https://doi.org/10.1016/j.jafrearsci.2019.103669. Gärtner A., Villeneuve M., Linnemann U., El Archi A. & Bellon H. (2013) - An exotic terrane of Laurussian affinity in the Mauritanides and Souttoufides (Moroccan Sahara). Gondwana Research, 24, 687-699. https://doi.org/10.1016/j. gr.2012.12.019. Pereira M.F., El Houicha M., Chichorro M., Armstrong R., Jouhari A., El Attari A., Ennih N. & Silva J.B. (2015) - Evidence of a Paleoproterozoic basement in the Moroccan Variscan Belt (Rehamna Massif, Western Meseta). Precambrian Res., 268, 61-73. https://doi.org/10.1016/j.precamres.2015.07.010. Tahiri A., Montero P., El Hadi H., Martínez Poyatos D., Azor A., Bea F., Simancas J.F. & González Lodeiro F. (2010) - Geochronological data on the Rabat-Tiflet granitoid: Their bearing on the tectonics of the Moroccan Variscides. Journal of African Earth Sciences, 57, 1-13, https://doi.org/10.1016/j.jafrearsci.2009.07.00.
Provenance of the Pre-orogenic Lower-Middle Jurassic successions of the Prerif foreland basin (Rif chain, Morocco).
Criniti S.;Critelli S.;
2023-01-01
Abstract
This study deals with the provenance of lower-middle Jurassic successions cropping out in the Prerif Foreland basin of the Rif chain (Morocco), by merging sedimentary petrology and U-Pb zircon geochronology on four stratigraphic successions to ensure a thorough new overview. The analyzed sandstone suites have been collected from the lower-Middle Jurassic sandstones of Jbel Outita, Jbel Zerhoune, and Dhar N’sour sections accumulated in different depositional paleoenvironments evolving down-slope from proximal delta to bathyal and deep-sea basin. Both lithofacies belonged to the hyper-extended margin of the NW-Gondwana during the early-middle Jurassic time coevally with the earliest rifting-drifting stages of the western edge of the Tethyan Ocean. Modal petrographic analyses show that sandstones are hybrid siliciclastic characterized by feldspathic litharenite, litharenite, and lithic arkose compositions. Detrital sandstone modes reveal a provenance from medium to high-grade metamorphic rocks namely of Transitional Continental block and recycled orogen. Reliable new U/Pb zircon data (LA-ICP-MS) from sandstone outcropping in the Prerif Basin were carried out on two samples from Jbel Zerhoune and Jbel Outita. Concordant U/Pb zircon data yielded a Paleozoic zircon age that shows provenance from the exotic Sehoul Bloc, High Atlas, and Anti-Atlas chains (Tahiri et al., 2010). Neoproterozoic cluster ages with a dominant Ediacaran zircon population at the peak (612 Ma- 598 Ma) corresponds to the Cadomian and/or the Pan-African orogens mainly of the “Sehoul block” exotic Terrane, Western Meseta, and Anti Atlas chains (El Haibi et al., 2020). Hence, rare Paleoproterozoic ages are less abundant with a peak age at 2.13 Ga, suggesting a provenance from the Anti-Atlas or probably from the Eburnean orogens of the West African Craton (WAC). (Pereira et al., 2015, Gärtner et al., 2013). EL Haibi H., EL Hadi H., Tahiri A., Martínez Poyatos D., Gasquet D., Pérez-Cáceres I., González Lodeiro F. & Mehdioui S. (2020) - Geochronology and isotopic geochemistry of Ediacaran high-K calc-alkaline felsic volcanism: An example of a Moroccan perigondwanan (Avalonian?) remnant in the El Jadida horst (Mazagonia). Journal of African Earth Sciences. https://doi.org/10.1016/j.jafrearsci.2019.103669. Gärtner A., Villeneuve M., Linnemann U., El Archi A. & Bellon H. (2013) - An exotic terrane of Laurussian affinity in the Mauritanides and Souttoufides (Moroccan Sahara). Gondwana Research, 24, 687-699. https://doi.org/10.1016/j. gr.2012.12.019. Pereira M.F., El Houicha M., Chichorro M., Armstrong R., Jouhari A., El Attari A., Ennih N. & Silva J.B. (2015) - Evidence of a Paleoproterozoic basement in the Moroccan Variscan Belt (Rehamna Massif, Western Meseta). Precambrian Res., 268, 61-73. https://doi.org/10.1016/j.precamres.2015.07.010. Tahiri A., Montero P., El Hadi H., Martínez Poyatos D., Azor A., Bea F., Simancas J.F. & González Lodeiro F. (2010) - Geochronological data on the Rabat-Tiflet granitoid: Their bearing on the tectonics of the Moroccan Variscides. Journal of African Earth Sciences, 57, 1-13, https://doi.org/10.1016/j.jafrearsci.2009.07.00.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
