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oai:docta.ucm.es:20.500.14352/713082023-07-13T02:31:13Zcom_20.500.14352_14col_20.500.14352_15

00925njm 22002777a 4500 dc Rodríguez, Carmen author Castro, Antonio author Gómez Frutos, Daniel author Gutiérrez Alonso, Gabriel author Pereira, Manuel Francisco author Fernández, Carlos author 2022-02-03 Cambro–Ordovician silicic magmatism in the Central Iberian Zone of the Iberian Massif (Ollo de Sapo Formation, OSF) constitutes a voluminous and geochemically atypical magmatic event that formed preceding the breakup of the northern margin of Gondwana. To date, and due to uncommon geochemical signatures, such as a high Fe, Mg content compared to anatectic melts and the departing from the calc-alkaline trends, the origin of such magmatic event is not fully understood. Herein, we report a data-analysis of geochemistry linking magmas and source compositions. The analysis of the combined data from multiple studies ascribes the geochemistry of the OSF rocks to a combination of extensive melting of Ediacaran metasiliciclastic rocks and a Ca-rich component. It is hypothesized that fluids released by crystallization of mafic magmas contributed to partial melting of a thick metasedimentary pile represented by Ediacaran siliciclastic rocks. Such melting event gave rise to a mobile nebulite or migma, which was able to extrude and form the super-eruption or “flare-up” that characterizes Cambro-Ordovician silicic magmatism at the Gondwana margin. Fast, catastrophic crustal melting with large-scale restite entrainment, triggered by the influx of mafic magma-derived fluids, are considered the main cause of the unique features of this Cambro-Ordovician atypical silicic large igneous province of Gondwana. 1342-937X 10.1016/j.gr.2022.01.011 https://hdl.handle.net/20.500.14352/71308 https://doi.org/10.1016/j.gr.2022.01.011 https://www.sciencedirect.com/ The unique Cambro-Ordovician silicic large igneous province of NW Gondwana: Catastrophic melting of a thinned crust