The Cordon del Portillo Permian magmatism, Mendoza, Argentina, plutonic and volcanic sequences at the western margin of Gondwana

Gregori, Daniel Alfredo; Benedini, Leonardo

doi:10.1016/j.jsames.2012.07.010

Cited by 20 publications

(10 citation statements)

References 16 publications

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“…With the idea of refining Hoke et al . 43 ’s previous results, two granite-granodiorite plutons of Permo-Triassic age (Cerro Punta Negra and Punta Blanca 50,51 ) were specifically sampled within the core of the Frontal Cordillera (Argentina) at ~33.5°S (Fig. 1c).…”

Section: Methodology and Sampling Strategysupporting

confidence: 60%

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Early exhumation of the Frontal Cordillera (Southern Central Andes) and implications for Andean mountain-building at ~33.5°S

Riesner

Simões

Carrizo³

et al. 2019

Sci Rep

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The Andes are the modern active example of a Cordilleran-type orogen, with mountain-building and crustal thickening within the upper plate of a subduction zone. Despite numerous studies of this emblematic mountain range, several primary traits of this orogeny remain unresolved or poorly documented. The onset of uplift and deformation of the Frontal Cordillera basement culmination of the Southern Central Andes is such an example, even though this structural unit appears as a first-order topographic and geological feature. To solve for this, new (U-Th)/He ages on apatite and zircon from granitoids of the Frontal Cordillera at ~33.5°S are provided here. These data, interpreted as an age-elevation thermochronological profile, imply continuous exhumation initiating well before ~12–14 Ma, and at most by ~22 Ma when considering the youngest zircon grain from the lowermost sample. The age of exhumation onset is then refined to ~20 Ma by combining these results with data on sedimentary provenance from the nearby basins. Such continuous exhumation since ~20 Ma needs to have been sustained by tectonic uplift on an underlying crustal-scale thrust ramp. Such early exhumation and associated uplift of the Frontal Cordillera invalidate the classically proposed east-vergent models of the Andes at this latitude. Additionally, they provide further support to recent views on Andean mountain-building proposing that the Andes at ~33.5°S grew firstly over west-vergent basement structures.

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Section: Methodology and Sampling Strategysupporting

confidence: 60%

“…All the data from this study are provided in detail in Tables S1 to S3 (Supplementary Materials). The pluton crystallization age is taken from published maps and data 50,51 . ( b ) Detail of the age-elevation profile for the 0–25 Ma time frame using the data obtained in this study.…”

Section: Introductionmentioning

confidence: 99%

Early exhumation of the Frontal Cordillera (Southern Central Andes) and implications for Andean mountain-building at ~33.5°S

Riesner

Simões

Carrizo³

et al. 2019

Sci Rep

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show abstract

“…All the data from this study are provided in detail in Tables S1 to S3 (Supplementary Materials). The pluton crystallization age is taken from published maps and data 50,51 . www.nature.com/scientificreports www.nature.com/scientificreports/ age of exhumation initiation is discussed below, by testing its consistency with AHe exhumation ages and published data on nearby syntectonic basins.…”

Section: Thermochronology Resultsmentioning

confidence: 99%

Early exhumation of the Frontal Cordillera (Southern Central Andes) and implications for Andean mountain-building at ~33.5°S

Riesner¹,

Simões²,

Carrizo³

et al. 2019

Preprint

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The Andes are the modern active example of a Cordilleran-type orogen, with mountain-building and crustal thickening within the upper plate of a subduction zone. Despite numerous studies of this emblematic mountain range, several primary traits of this orogeny remain unresolved or poorly documented. The onset of uplift and deformation of the Frontal Cordillera basement culmination of the Southern Central Andes is such an example, even though this structural unit appears as a first-order topographic and geological feature. To solve for this, new (U-Th)/He ages on apatite and zircon from granitoids of the Frontal Cordillera at ~33.5°S are provided here. These data, interpreted as an age-elevation thermochronological profile, imply continuous exhumation initiating well before ~12-14 Ma, and at most by ~22 Ma when considering the youngest zircon grain from the lowermost sample. The age of exhumation onset is then refined to ~20 Ma by combining these results with data on sedimentary provenance from the nearby basins. Such continuous exhumation since ~20 Ma needs to have been sustained by tectonic uplift on an underlying crustal-scale thrust ramp. Such early exhumation and associated uplift of the Frontal Cordillera invalidate the classically proposed east-vergent models of the Andes at this latitude. Additionally, they provide further support to recent views on Andean mountain-building proposing that the Andes at ~33.5°S grew firstly over west-vergent basement structures.

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“…Ignimbrites and rhyolitic tuffs are also present in the uppermost part of the sequence (Tobares et al 2015). In this context, the lowermost part of the Choiyoi Group would represent an intermediate to mafic subductionrelated magmatism (Gregori and Benedini, 2013) whilst, the breccias could be the end product of the fracturing and opening of vents at the initial stages of the volcanic eruption. Based on field relationships and lithological similarities, the mafic facies has been correlated to the Portezuelo del Cenizo Fm., outcropping in region of Quebrada del Tigre, north of the study area (Folguera et al 2001).…”

Section: Lithological Faciesmentioning

confidence: 99%

“…As the backbone of the Andes of southern South America and being one of the most important geological units of Argentina, the Choiyoi has been extensively studied over the years (e.g. Gonzalez Diaz, 1957;Stipanicic et al 1968;Ramos et al 1988;Gregori and Benedini, 2013;Sato et al 2015;Spalletti and Limarino, 2017;and many others.). Despite the large amount of work that has been done, the large geographical extent, lithological diversity and complex structural setting, means that a clear understanding of the origin and evolution of the Choiyoi is still elusive.…”

Section: Introductionmentioning

confidence: 99%

The Choiyoi Group in the Cordón del Plata range, western Argentina: structure, petrography and geochemistry

et al. 2020

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The Choiyoi Group from the Permo-Triassic, is one of the most conspicuous volcano-sedimentary suites of southern South America, considered critical to understand the geological evolution of the western margins of Gondwana. In this regard, petrography, geochemistry, and structural data were examined to better elucidate the physical character and emplacement conditions of the unit in the Cordon del Plata range, within the Frontal Cordillera of Mendoza, Argentina. The site is representative of the magmatism and deformation through different Andean cycles. Results of the study indicate three lithological facies of increasing acidity upwards. Mafic units consist of basalts, andesite and andesitic breccias at the base of the sequence. Felsic rocks such as rhyodacites, granites and welded tuffs are predominant above. The fault zone of La Polcura – La Manga is the most prominent structural feature in the region, which presumably controlled the emplacement of breccias and ignimbrites within the middle and upper members. These compositional variations suggest a magma evolution from subduction to a rifting environment after the San Rafael orogeny in the Late Palaeozoic. In this line, the Lower Choiyoi was observed to overlie the San Rafael structures indicating thus, that compression ceased before the volcanic extrusion. Geochemistry data indicate that mafic rocks are mostly high-potassium, calc-alkaline volcanics derived from the mantle wedge above the subduction zone. In contrast, the felsic rocks range from high-potassium rhyolites to shoshonites, typically depleted in Eu. This indicate partial melting of a lithospheric mantle in an average to thin crust.

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The Cordon del Portillo Permian magmatism, Mendoza, Argentina, plutonic and volcanic sequences at the western margin of Gondwana

Cited by 20 publications

References 16 publications

Early exhumation of the Frontal Cordillera (Southern Central Andes) and implications for Andean mountain-building at ~33.5°S

Early exhumation of the Frontal Cordillera (Southern Central Andes) and implications for Andean mountain-building at ~33.5°S

Early exhumation of the Frontal Cordillera (Southern Central Andes) and implications for Andean mountain-building at ~33.5°S

The Choiyoi Group in the Cordón del Plata range, western Argentina: structure, petrography and geochemistry

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