The mafic dikes from the Panticosa pluton (Pyrenean Axial Zone): petrology and mineral chemistry

• Autores: Pablo Tierz López, Marceliano Lago San José, Carlos Galé Bornao, Enrique Arranz Yagüe, Teresa Ubide, Patricia Larrea, Tomás Sanz Serrano
• Localización: Geogaceta, ISSN 0213-683X, Nº. 51, 2012, págs. 15-18
• Idioma: inglés
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• Resumen

  • The Panticosa pluton is one of multiple granitic plutons cropping out in the Pyrenean Axial Zone, which corresponds to the Palaeozoic core of the Pyrenees. Mafic dikes cut both the Panticosa pluton and its Devonian metasedimentary country rocks. According to their mineralogy and mineral composition, these dikes can be classified into two different groups, with little textural variations: a calc-alkaline group and an alkaline group. The calcalkaline rocks (spessartites and calc-alkaline diabases) include calcic to sodic Pl, slightly Ti-rich Amp and substantial Qz. In contrast, the alkaline rocks (camptonites and alkaline diabases) are composed of calcic Pl, Ti-rich Cpx, Ol pseudomorphs and inherited constituents (megacrysts and enclaves). The composition of Pl and the main ferromagnesian phase (Amp in calc-alkaline group and Cpx in alkaline group) is coherent with the geochemical affinity assigned to both groups. The megacrysts in the alkaline group are predominantly Krs and Ts, with a deep-origin according to thermobarometric calculations. A detailed mineral chemistry study of the phases observed inside the enclaves is necessary to better comprehend the petrogenesis of the magmas which generated these alkaline rocks.