Revista de la Asociación Geológica Argentina, 2010
... a diferentes escalas del borde occidental de la Precordillera de San Juan a lo ... El trabajo... more ... a diferentes escalas del borde occidental de la Precordillera de San Juan a lo ... El trabajo de Sellés-Martínez y Azcurra marca una transición entre las contribuciones de los ... Deseamos expresar nuestro reconocimiento a los árbitros: Carlos Cingolani, José María Cortés, Ernesto ...
Regional-scale transpression and transtension are considered to be important in the lower Paleozo... more Regional-scale transpression and transtension are considered to be important in the lower Paleozoic tectono-magmatic evolution of metamorphic and granitoid basement rocks of the southern central Andes. In order to test whether such kinematic changes affected Paleozoic basement rocks on the local scale, i.e. in the Eastern Cordillera of NW-Argentina, we performed a detailed field-based structural analysis of the 456 Ma granitoid Cerro Durazno pluton (CDP). The results of our analysis point to the following stages in the geodynamic evolution of this area: (1) Metamorphism and deformation of Neoproterozoic-Paleozoic basement rocks occurred at high T and low to medium P prior to emplacement of the CDP. This lead to the formation of schists and migmatites characterized by pervasive planar and linear mineral shape fabrics and the growth of andalusite, cordierite and fibrolite. (2) Magmatic foliation in the CDP is defined by the shape-preferred orientation of euhedral feldspar phenocrysts ...
The Tastil batholith composed of gray granodiorite, red granite and dacite porphiry, intrudes int... more The Tastil batholith composed of gray granodiorite, red granite and dacite porphiry, intrudes into weakly metamorphosed turbidites (usually included in the Puncoviscana Formation) and into Cambrian shelf sandstones belonging to the Lower-Middle Cambrian Mesón Group deposited in an intracontinental extensional basin. Tremadocian fossiliferous conglomerates overlying the sandstones of the Mesón Group incorporate red granite pebbles in the Angosto de la
Los granitoides de Brealito y La Paya son plutones de formas elípticas alargadas en dirección N-S... more Los granitoides de Brealito y La Paya son plutones de formas elípticas alargadas en dirección N-S emplazados respectivamente en las Formaciones Puncoviscana y La Paya. El estudio de la estructura interna de los plutones se ha abordado aplicando la anisotropía de la susceptibilidad magnética (ASM). El plutón de La Paya presenta un carácter paramagnético (K entre 1,9 y 6,7 x10-
Se postula un modelo por el cual las diferencias en la evolución del volcanismo de la Puna septen... more Se postula un modelo por el cual las diferencias en la evolución del volcanismo de la Puna septentrional y austral son consecuencias de cambios sustanciales en los estilos estructurales que, de norte a sur, presenta el frente orogénico andino en el antepaís. Los frentes orogénicos que representan las Sierras Subandinas al norte, el Sistema de Santa Bárbara en el centro
Normal faults are often observed in many compressional Cenozoic mountain belts and paleotectonic ... more Normal faults are often observed in many compressional Cenozoic mountain belts and paleotectonic settings and have been associated with a late-stage development in orogen evolution. Often, such normal faults are found in high-elevation sectors in the orogen interior and may form graben, closely spaced arrays or they are kinematically linked with strike-slip faults. In contrast, at lower elevations and in
The geologi e process es that concemed the Andean uplift and related basins in the northwest of A... more The geologi e process es that concemed the Andean uplift and related basins in the northwest of Argentina from middle Miocene to Recent are quite weil known. Before this period, the manner in which the Palaeogene postrift basin evolved to the foreland basin and mainly, in which moment this transformation took place, are still uncertain . In this contribution new
The southern portion of the Cobres Range is studied with an interdisciplinary, petrological–geoch... more The southern portion of the Cobres Range is studied with an interdisciplinary, petrological–geochemical and structural-cartographic approach. The Cobres Plutonic Complex (CPC) consists of two main plutons, a granodiorite and a monzogranite, as well as small bodies of gabbros, acidic dikes, and episyenite bands. Their mineralogy and geochemistry suggest a comagmatic character for both plutons, which are strongly peraluminous and define a typical calc–alkaline trend. Harker diagrams indicate a fractionated crystallization trend. The REEs have similar patterns for enclaves, granodiorites, monzogranites, aplites, and acidic dikes, also similar to those from the upper crust rocks. Gabbros included in the CPC show geochemical signatures compatible with the mantle. The CPC is syntectonic, though the granodioritic and monzogranitic plutons represent different stages in the tectomagmatic history of the region. The geology of the CPC and its regional framework show characteristics—thermal anomalies, alternation of contractional and extensional deformational events, magmatic rocks with crustal and mantle affiliations, and contemporaneous extensional basins—that indicate intrusion of the CPC in an extensional accretionary orogen.
Revista de la Asociación Geológica Argentina, 2010
... a diferentes escalas del borde occidental de la Precordillera de San Juan a lo ... El trabajo... more ... a diferentes escalas del borde occidental de la Precordillera de San Juan a lo ... El trabajo de Sellés-Martínez y Azcurra marca una transición entre las contribuciones de los ... Deseamos expresar nuestro reconocimiento a los árbitros: Carlos Cingolani, José María Cortés, Ernesto ...
Regional-scale transpression and transtension are considered to be important in the lower Paleozo... more Regional-scale transpression and transtension are considered to be important in the lower Paleozoic tectono-magmatic evolution of metamorphic and granitoid basement rocks of the southern central Andes. In order to test whether such kinematic changes affected Paleozoic basement rocks on the local scale, i.e. in the Eastern Cordillera of NW-Argentina, we performed a detailed field-based structural analysis of the 456 Ma granitoid Cerro Durazno pluton (CDP). The results of our analysis point to the following stages in the geodynamic evolution of this area: (1) Metamorphism and deformation of Neoproterozoic-Paleozoic basement rocks occurred at high T and low to medium P prior to emplacement of the CDP. This lead to the formation of schists and migmatites characterized by pervasive planar and linear mineral shape fabrics and the growth of andalusite, cordierite and fibrolite. (2) Magmatic foliation in the CDP is defined by the shape-preferred orientation of euhedral feldspar phenocrysts ...
The Tastil batholith composed of gray granodiorite, red granite and dacite porphiry, intrudes int... more The Tastil batholith composed of gray granodiorite, red granite and dacite porphiry, intrudes into weakly metamorphosed turbidites (usually included in the Puncoviscana Formation) and into Cambrian shelf sandstones belonging to the Lower-Middle Cambrian Mesón Group deposited in an intracontinental extensional basin. Tremadocian fossiliferous conglomerates overlying the sandstones of the Mesón Group incorporate red granite pebbles in the Angosto de la
Los granitoides de Brealito y La Paya son plutones de formas elípticas alargadas en dirección N-S... more Los granitoides de Brealito y La Paya son plutones de formas elípticas alargadas en dirección N-S emplazados respectivamente en las Formaciones Puncoviscana y La Paya. El estudio de la estructura interna de los plutones se ha abordado aplicando la anisotropía de la susceptibilidad magnética (ASM). El plutón de La Paya presenta un carácter paramagnético (K entre 1,9 y 6,7 x10-
Se postula un modelo por el cual las diferencias en la evolución del volcanismo de la Puna septen... more Se postula un modelo por el cual las diferencias en la evolución del volcanismo de la Puna septentrional y austral son consecuencias de cambios sustanciales en los estilos estructurales que, de norte a sur, presenta el frente orogénico andino en el antepaís. Los frentes orogénicos que representan las Sierras Subandinas al norte, el Sistema de Santa Bárbara en el centro
Normal faults are often observed in many compressional Cenozoic mountain belts and paleotectonic ... more Normal faults are often observed in many compressional Cenozoic mountain belts and paleotectonic settings and have been associated with a late-stage development in orogen evolution. Often, such normal faults are found in high-elevation sectors in the orogen interior and may form graben, closely spaced arrays or they are kinematically linked with strike-slip faults. In contrast, at lower elevations and in
The geologi e process es that concemed the Andean uplift and related basins in the northwest of A... more The geologi e process es that concemed the Andean uplift and related basins in the northwest of Argentina from middle Miocene to Recent are quite weil known. Before this period, the manner in which the Palaeogene postrift basin evolved to the foreland basin and mainly, in which moment this transformation took place, are still uncertain . In this contribution new
The southern portion of the Cobres Range is studied with an interdisciplinary, petrological–geoch... more The southern portion of the Cobres Range is studied with an interdisciplinary, petrological–geochemical and structural-cartographic approach. The Cobres Plutonic Complex (CPC) consists of two main plutons, a granodiorite and a monzogranite, as well as small bodies of gabbros, acidic dikes, and episyenite bands. Their mineralogy and geochemistry suggest a comagmatic character for both plutons, which are strongly peraluminous and define a typical calc–alkaline trend. Harker diagrams indicate a fractionated crystallization trend. The REEs have similar patterns for enclaves, granodiorites, monzogranites, aplites, and acidic dikes, also similar to those from the upper crust rocks. Gabbros included in the CPC show geochemical signatures compatible with the mantle. The CPC is syntectonic, though the granodioritic and monzogranitic plutons represent different stages in the tectomagmatic history of the region. The geology of the CPC and its regional framework show characteristics—thermal anomalies, alternation of contractional and extensional deformational events, magmatic rocks with crustal and mantle affiliations, and contemporaneous extensional basins—that indicate intrusion of the CPC in an extensional accretionary orogen.
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