Massive Jurassic slab break-off revealed by a multidisciplinary reappraisal of the Chon Aike silicic large igneous province

• Autores: Navarrete, César; Gianni, Guido; Tassara, Santiago; Zaffarana, Claudia Beatriz; Likerman, Jeremias; Márquez, Marcelo; Wostbrock, Jordan; Planavsky, Noah; Tardani, Daniele; Perez Frasette, Maximiliano
• Año de publicación: 2023
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Ciencias Exactas y Naturales; SLIP; Jurassic; Gondwana; Ciencias Exactas y Naturales
• Institución: Universidad Nacional de Río Negro

Fil: Navarrete, César. Petro-Tectonic Patagonian Lab, National University of Patagonia San Juan Bosco. National Scientific and Technical Research Council (CONICET). Argentina.
Fil: Gianni, Guido. National Scientific and Technical Research Council (CONICET). Seismological Geophysical Institute Eng. Fernando Volponi (IGSV), National University of San Juan. Argentina.
Fil: Tassara, Santiago. Instituto de Ciencias de la Ingeniería, Universidad de O’Higgins. Department of Earth and Planetary Sciences, Yale University, New Haven. Estados Unidos.
Fil: Zaffarana, Claudia Beatriz. National Scientific and Technical Research Council (CONICET). National University of Rio Negro. Institute for Research in Paleobiology and Geology. Argentina.
Fil: Likerman, Jeremias. National Scientific and Technical Research Council (CONICET). Don Pablo Groeber Institute of Andean Studies, University of Buenos Aires. Argentina.
Fil: Márquez, Marcelo. Petro-Tectonic Patagonian Lab, National University of Patagonia San Juan Bosco. Argentina.
Fil: Wostbrock, Jordan. Department of Earth and Planetary Sciences, Yale University, New Haven. Estados Unidos.
Fil: Planavsky, Noah. Department of Earth and Planetary Sciences, Yale University, New Haven. Estados Unidos.
Fil: Tardani, Daniele. Instituto de Ciencias de la Ingeniería, Universidad de O’Higgins. Chile.
Fil: Perez Frasette, Maximiliano. Petro-Tectonic Patagonian Lab, National University of Patagonia San Juan Bosco. National Scientific and Technical Research Council (CONICET). Argentina.
The origin of the Chon Aike silicic large igneous province (SLIP) is a matter of intense debate, with contrasting hypotheses that range from intraplate settings linked to mantle plume impingement to subduction-related pro­ tracted arc magmatism in an active margin. In this study, we propose a new model for the origin of this SLIP based on a multidisciplinary dataset from Patagonia, a comprehensive literature review of southwestern Gondwana, and the results of 2-D thermochemical modeling. We demonstrate that the partial melting of sub­ ducted rocks during a massive slab break-off and the subsequent piecemeal sinking of a previously flattened oceanic lithosphere beneath southwestern Gondwana best reconciles most of the data from this magmatic province. Geophysical, geochronological, geochemical, and isotopic data from Chon Aike SLIP, combined with the understanding of the tectonic regime, ore deposits, Jurassic geological events in southwestern Gondwana and numerical modeling results, support an origin primarily linked to the partial melting of partially eclogitized metabasaltic and metasedimentary rocks, enhanced by a warm ambient mantle associated with supercontinent thermal insulation and the thermal effects of the Karoo mantle plume impingement. The demise of the flat slab through large-scale slab break-off would have led to the partial melting of a mixture largely composed of these extensively underplated components and mantle batches. These melts would have variably interacted with mantle and continental rocks and melts, resulting in the formation of most of the Chon Aike SLIP. The reestablishment of the magmatic arc after the initial stages of slab break-off seems to have only affected the northwestern part of this SLIP.
The origin of the Chon Aike silicic large igneous province (SLIP) is a matter of intense debate, with contrasting hypotheses that range from intraplate settings linked to mantle plume impingement to subduction-related pro­ tracted arc magmatism in an active margin. In this study, we propose a new model for the origin of this SLIP based on a multidisciplinary dataset from Patagonia, a comprehensive literature review of southwestern Gondwana, and the results of 2-D thermochemical modeling. We demonstrate that the partial melting of sub­ ducted rocks during a massive slab break-off and the subsequent piecemeal sinking of a previously flattened oceanic lithosphere beneath southwestern Gondwana best reconciles most of the data from this magmatic province. Geophysical, geochronological, geochemical, and isotopic data from Chon Aike SLIP, combined with the understanding of the tectonic regime, ore deposits, Jurassic geological events in southwestern Gondwana and numerical modeling results, support an origin primarily linked to the partial melting of partially eclogitized metabasaltic and metasedimentary rocks, enhanced by a warm ambient mantle associated with supercontinent thermal insulation and the thermal effects of the Karoo mantle plume impingement. The demise of the flat slab through large-scale slab break-off would have led to the partial melting of a mixture largely composed of these extensively underplated components and mantle batches. These melts would have variably interacted with mantle and continental rocks and melts, resulting in the formation of most of the Chon Aike SLIP. The reestablishment of the magmatic arc after the initial stages of slab break-off seems to have only affected the northwestern part of this SLIP.