Resumo

VIZAN, Haroldo  e  LAGORIO, Silvia Leonor. Modelo geodinámico de los procesos que generaron el volcanismo cretácico de Córdoba (Argentina) y la Gran Provincia Ígnea Paraná, incluyendo el origen y evolución de la "pluma" Tristán. Geoacta [online]. 2011, vol.36, n.1, pp.55-75. ISSN 1852-7744.

The aim of this paper is to present a geodynamic model coherent with lithologies that belong to two volcanic processes that occurred practically during the same geological time (at about 130 Ma) in Córdoba and in Misiones (Argentina). In this model it is considered what nowadays one knows of the processes of convection that ocurr in the terrestrial mantle. It is suggested that the alkaline cretaceous volcanism of Córdoba was generated fundamentally by edge driven convection between the craton of Río de La Plata and the terrane Pampia or the ancient mobile belt (suture zone) that separates both. On the other hand it is considered that the origin of the tholeiitic basalts of the Large Igneous Province of Paraná and its African counterpart in Etendeka and Angola localities was controlled by lateral convection of large scale induced by subduction, stimulated, also, by the caloric energy insulated by the supercontinent Pangea. It is suggested, in addition, that the "plume" called Tristán was actually a conduit of magma outpuring to evacuate the caloric energy insulated by this supercontinent. This conduit would be determined by lithosferic factors and would not correspond to a typical plume generated by a thermal discountinuity at the core-mantle boundary. This conduit could have being used as a guide for deep currents that transported to the surface chemical elements previously carried to deep zones of the mantle by former subducted slabs. It is suggested that the processes of convection in the mantle would be determined by the architecture and the dynamics of the lithosphere.

Palavras-chave : Córdoba, Misiones, Cretaceous, volcanism, Mantle convection.

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