Reviewing the geochemistry and petrology of the subcordilleran plutonic belt, early Jurassic magmatic arc in northern Patagonia

• Autores: Zaffarana, Claudia Beatriz; Orts, Darío Leandro; Gallastegui, Gloria; Suárez, Rodrigo; Poma, Stella; Pernich, Sebastián; Aramendía, Brenda
• Año de publicación: 2024
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Ciencias Exactas y Naturales; Slab roll-back; Arc magmatism; Mineral fractionation; Ciencias Exactas y Naturales
• Institución: Universidad Nacional de Río Negro

Fil: Zaffarana, Claudia Beatriz. Universidad Nacional de Río Negro, Instituto de Investigación en Paleobiología y Geología, CONICET. Argentina.
Fil: Orts, Darío Leandro. Universidad Nacional de Río Negro, Instituto de Investigación en Paleobiología y Geología, CONICET. Argentina.
Fil: Gallastegui, Gloria. Instituto Geológico y Minero de España (IGME-CSIC). España
Fil: Suárez, Rodrigo. Universidad Nacional de Río Negro, Instituto de Investigación en Paleobiología y Geología, CONICET. Argentina.
Fil: Poma, Stella. Instituto de Geociencias Basicas, Aplicadas y Ambientales de Buenos Aires (IGEBA, CONICET-UBA). Argentina.
Fil: Pernich, Sebastián. Universidad Nacional de Río Negro, Instituto de Investigación en Paleobiología y Geología, CONICET. Argentina.
Fil: Aramendía, Brenda. Universidad Nacional de Río Negro, Instituto de Investigación en Paleobiología y Geología, CONICET. Argentina.
The Subcordilleran Plutonic Belt, formed in Early Jurassic times, is a short-lived batholith that developed during Gondwana dismembering. In our study, we analyzed both well-known and potential new localities of the belt of plutonic rocks, considering new whole-rock geochemical data as well as data from the literature. Additionally, new geochemical data from five samples and one U-Pb zircon date are presented from the diorites and granodiorites from the Cerro Catedral, at Bariloche (41◦S). The obtained U-Pb age in zircon is Early Jurassic (192 ± 1.5 Ma). The granitoids of the Subcordilleran Plutonic Belt are calc-alkaline, of medium to high potassium. They exhibit similar alkali content than the granitoids of the Middle Jurassic-Cretaceous Patagonian Batholith, and lower alkalis than the volcanic and plutonic rocks of the Jurassic Chon Aike Silicic Large Igneous Province. These findings suggest that the Subcordilleran Plutonic Belt represents, in the region comprised within 39◦ and 45◦ S, an early stage of the Andean arc. Our observations indicate that while some granitoids in potential localities, such as Cerro Catedral, can now belong to the Subcordilleran Plutonic Belt, other sites, like Pilcaniyeu and Pilahue, may be associated with the plutonic facies of the Chon Aike Province. The Subcordilleran Plutonic Belt is an example of arc magmatism that developed during a period of major plate reorganization, along with the subduction of mature sea floor beneath the Gondwana margin, and the latter promoted slab roll-back processes and a subduction with extension tectonic regime.
The Subcordilleran Plutonic Belt, formed in Early Jurassic times, is a short-lived batholith that developed during Gondwana dismembering. In our study, we analyzed both well-known and potential new localities of the belt of plutonic rocks, considering new whole-rock geochemical data as well as data from the literature. Additionally, new geochemical data from five samples and one U-Pb zircon date are presented from the diorites and granodiorites from the Cerro Catedral, at Bariloche (41◦S). The obtained U-Pb age in zircon is Early Jurassic (192 ± 1.5 Ma). The granitoids of the Subcordilleran Plutonic Belt are calc-alkaline, of medium to high potassium. They exhibit similar alkali content than the granitoids of the Middle Jurassic-Cretaceous Patagonian Batholith, and lower alkalis than the volcanic and plutonic rocks of the Jurassic Chon Aike Silicic Large Igneous Province. These findings suggest that the Subcordilleran Plutonic Belt represents, in the region comprised within 39◦ and 45◦ S, an early stage of the Andean arc. Our observations indicate that while some granitoids in potential localities, such as Cerro Catedral, can now belong to the Subcordilleran Plutonic Belt, other sites, like Pilcaniyeu and Pilahue, may be associated with the plutonic facies of the Chon Aike Province. The Subcordilleran Plutonic Belt is an example of arc magmatism that developed during a period of major plate reorganization, along with the subduction of mature sea floor beneath the Gondwana margin, and the latter promoted slab roll-back processes and a subduction with extension tectonic regime.