The unique Cambro-Ordovician silicic large igneous province of NW Gondwana: Catastrophic melting of a thinned crust
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 signat...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2022 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/71308 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/71308 |
| Access Level: | acceso abierto |
| Palabra clave: | 552.3(46) Cambro-Ordovician magmatism Ollo de Sapo Formation Data-analysis Geochemical modelling Extensive crustal melting Petrología |
| Sumario: | 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. |
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