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Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/183927
The enriched Variscan lithosphere of NE Iberia: data from postcollisional Permian calc-alkaline lamprophyre dykes of Les Guilleries
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Post-collisional mafic dykes crosscut the Paleozoic metamorphic basement and late-Variscan plutons in Les Guilleries massif (Catalan Coastal Ranges, NE Iberia). The predominance of mafic phenocrysts, porphyritic texture, abundant amphibole, high MgO and volatile content, together with crustal-like trace-element patterns indicate that the dykes correspond to calc-alkaline lamprophyres, mainly spessartites. Their enrichment in LILE, HFSE and REE and initial Sr-Nd isotopic compositions (87Sr/86Sri between 0.70851 and 0.71127, ε Ndi between -5.23 and -4.63) are consistent with an enriched subcontinental lithospheric mantle source. U-Pb ages of matrix titanite crystals yield concordia ages of 262±7Ma, congruent with crosscutting relationships. Post-magmatic processes are evidenced by intense chloritization and albitization of the lamprophyres, together with systematic variations of Na2O vs SiO2, K2O, CaO, Ba, Rb, Cs, Pb, Sr, Tl, and Zn, and possibly the removal of F. The geochemical and geochronological data support an orogenic geochemical affinity, in accordance with the transitional tectonic regime between Variscan compression/transpression and post-collisional transtension/extension, related to the fragmentation of Pangea and thinning of the lithosphere. The lamprophyre dykes studied could represent the youngest pulse of Variscan orogenic magmatism and, therefore, mark its end in NE Iberia before the onset of the generalized Triassic extension. Calc-alkaline lamprophyre. Post-collisional dykes. Sr-Nd isotopes. Les Guilleries Massif. Catalan Coastal Ranges. Variscan Orogeny.KEYWORDSABSTRACTCitation: Mellado, E., Corbella, M., Navarro-Ciurana, D., Kylander-Clark, A., 2021. The enriched Variscan lithosphere of NE Iberia: data from post-collisional Permian calc-alkaline lamprophyre dykes of Les Guilleries.
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MELLADO, Esteban, et al. The enriched Variscan lithosphere of NE Iberia: data from postcollisional Permian calc-alkaline lamprophyre dykes of Les Guilleries. Geologica Acta. 2021. Vol. 19, num. 1-23. ISSN 1695-6133. [consulted: 11 of June of 2026]. Available at: https://hdl.handle.net/2445/183927