Magmatic evolution of the Austral Patagonian Andes

Ramos, Víctor A.; Niemeyer, Hans; Skarmeta, Jorge; ̃oz, J. Mun

doi:10.1016/0012-8252(82)90047-2

Cited by 87 publications

(72 citation statements)

References 27 publications

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“…This fold-and-thrust belt is associated along its eastern margin with a foreland basin (Austral Foreland Basin). This compression process extended from the Upper Cretaceous to the Neogene (Ramos et al, 1982;Biddle et al, 1986;Wilson, 1991;Spalletti and Franzese, 2007;Fosdick et al, 2011).…”

Section: Foreland Stagementioning

confidence: 99%

“…It has not been possible to determine the exact timing of obduction, but the compression associated with the early stages of the orogeny caused the development of a retroarc fold-and-thrust belt along the Patagonian-Fuegian Andes (Ramos et al, 1982;Biddle et al, 1986;Wilson, 1991;Fildani et al, 2003;Fildani and Hessler, 2005). This fold-and-thrust belt is associated along its eastern margin with a foreland basin (Austral Foreland Basin).…”

Section: Foreland Stagementioning

confidence: 99%

“…Between the middle Cenomanian and the lower Coniacian (96-84 Ma), a deformation event occurred which could be related to the closure of the Rocas Verdes Marginal Basin (Ramos et al, 1982;Biddle et al, 1986). The onset of the compressional phase in the middle sector of the Austral Basin is characterized by the west to east progradation of the fluvial-estuarine facies of the Mata Amarilla Formation (Varela, 2009(Varela, , 2011.…”

Section: Foreland Stagementioning

confidence: 99%

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U-Pb zircon constraints on the age of the Cretaceous Mata Amarilla Formation, Southern Patagonia, Argentina: its relationship with the evolution of the Austral Basin

Varela

Poiré

Martin

et al. 2012

andgeo

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ABSTRACT. Despite the abundant fossil content of the Mata Amarilla Formation (Southern Patagonia, Santa Cruz Province, Argentina), its age has always generated a considerable number of questions and debates. The chronological data provided by invertebrates, dinosaurs, fish, turtles, plesiosaurs and fossil flora are contradictory. In this work, twenty U-Pb spot analyses by laser ablation were carried out on the outer parts of the zoned zircon crystals from a tuff layer of the middle section of the Mata Amarilla Formation, yielding a U-Pb concordia age of 96.23±0.71 Ma, which corresponds to the middle Cenomanian. The deposition of the lower section of the Mata Amarilla Formation marks the onset of the foreland stage of the Austral Basin (also known as Magallanes Basin); this transition is characterized by the west-east shift of the depositional systems, which is consistent with the progradation of the Cretaceous fold-and-thrust belt. Thus, the onset of the foreland stage could have occurred between the upper Albian and lower Cenomanian, as the underlying Piedra Clavada Formation is lower Albian in age. On comparing the data obtained with information from the Última Esperanza Province in Chile, it can be suggested that the initiation of the closure of the Rocas Verdes Marginal Basin occurred simultaneously. RESUMEN. Edades U-Pb en circones de la FormaciónMata Amarilla (Cretácico), Patagonia Austral, Argentina: su relación con la evolución de la Cuenca Austral. A pesar del abundante contenido fosilífero de la Formación Mata Amarilla (Patagonia Austral, Provincia de Santa Cruz, Argentina), siempre se generaron abundantes dudas y debates acerca de cuál es la edad de esta formación. Los datos cronológicos aportados por los invertebrados, los dinosaurios, peces, tortugas, plesiosaurios y flora fósil son dispares. En el presente trabajo se obtuvo una edad U-Pb concordia por la metodología de ablación láser aplicada a 20 puntos de la parte externa de circones zonados provenientes de un nivel tobáceo hallado en la sección media de la Formación Mata Amarilla, lo cual arrojó una edad de 96,23±0,71 Ma, que corresponde al Cenomaniano medio. La depositación de la sección inferior de la Formación Mata Amarilla marca el inicio del estadio de antepaís de la Cuenca Austral (también conocida como Cuenca de Magallanes); este pasaje está signado por el cambio oeste-este de los sistemas depositacionales, los cuales se encuentran en concordancia con la progradación de la faja plegada y corrida cretácica. Así, el comienzo del estadio de antepaís quedaría comprendido entre el Albiano superior y el Cenomaniano inferior, debido a que la subyacente Formación Piedra Clavada posee una edad Albiano inferior. Al comparar estos resultados con los datos de la Provincia de Última Esperanza en Chile, se sugiere que el comienzo del cierre de la cuenca marginal de Rocas Verdes se produjo en forma simultánea.

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Section: Foreland Stagementioning

confidence: 99%

Section: Foreland Stagementioning

confidence: 99%

Section: Foreland Stagementioning

confidence: 99%

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U-Pb zircon constraints on the age of the Cretaceous Mata Amarilla Formation, Southern Patagonia, Argentina: its relationship with the evolution of the Austral Basin

Varela

Poiré

Martin

et al. 2012

andgeo

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“…Eruptive centers are aligned following old lines of structural weakness reactivated by the Andean orogeny (Ramos et al, 1982). Lava flows, characterized as olivine and alkaline basalts, belong to intraplate volcanism (Massaferro et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Paleomagnetism of the late Cenozoic basalts from northern Patagonia

et al. 2006

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Late Cenozoic volcanic rocks outcrop in the northern Patagonia Extrandina. Lava flows, characterized as olivine and alkaline basalts, belong to intraplate volcanism. We report paleomagnetic and rock-magnetic studies carried out on Late Cenozoic basalts belonging to the Cráter, Mojón and Moreniyeu Formations. The paleomagnetic sampling comprised 75 sites in lava flows and dikes from the Cráter Formation, three sites in a lava flow from the Mojón Formation and three sites in a lava flow from the Moreniyeu Formation. Alternating field (AF) and thermal detailed demagnetization techniques were used. Most of the samples have a viscous component. The AF procedure was more effective than thermal demagnetization in destroying viscous components and in defining the characteristic remanent magnetizations. Demagnetization curves and rock-magnetic studies suggest that the main remanence carrier is Ti-poor magnetite. Radiometric K-Ar ages were performed on these basalts. The radiometric ages are 0.8±0

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“…Ramos et al (1982) mencionan pequedos stocks, de edad miocena, que afloran a lo largo del borde este del Batolito Patagbnico, de composicibn calco-alcalina a alcalina, entre ellos el del Fitz Roy y otros como el San Lorenzo y el Paine; estos cuerpos estarian desconectados superficialmente del Batolito Patag6nico.…”

unclassified

Fitz Roy granite characterization Province of Santa Cruz, Argentina

Kosmal¹,

Spikermann²

2002

MACN

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Characterization o f the Fitz Roy granite, province o f Santa Cruz, Argentina. The Miocene aged Fitz Roy granite is located at 73" 4' W and 49" 16' S in the province of Santa Cruz, Argentina. It is a 45 kin2 stock of ovoidal section, being its major axes of approximately 16 km EW and 9 km NS direction. Its character is epizonal, and zonal in its transversal sense facies. A marginal dark microdioritic facies and a main graniticgranodioritic facies are clearly seen. The box is made up of leptomorphytes of the Paleozoic Formation Bahia de la Lancha, vulcanogenic Jurassic rocks of the Complejo el Queinado and Cretaceous sedimentites of the Rio Mayer Formation. Both facies are chalcoalkalines of medium to high potassic alkalinity. The dioritic facies is alumina infrasaturated, whereas the granitic main facies presents meta and peraluminous saturation terms.Key words: Fitz Roy pluton, geochemistry, Patagonia, Argentina. Ramos et al. (1982) mencionan pequedos stocks, de edad miocena, que afloran a lo largo del borde este del Batolito Patagbnico, de composicibn calco-alcalina a alcalina, entre ellos el del Fitz Roy y otros como el San Lorenzo y el Paine; estos cuerpos estarian desconectados superficialmente del Batolito Patag6nico.El Batolito Patag6nico esta expuesto desde 10s 39" hasta 10s 56" de latitud sur, siendo el tipo de roca dominante la tonalita (Wells, 1979, in Ramos et al., 1982. Se&n una transecta a 10s 45" de latitud S, este se puede dividir en tres grupos: las rocas basicas occidentales, las centrales intermedias y las acidas orientales, que presentan en general una tendencia calcoalcalina (Ramos et al., 1982). El emplazamieto del Batolito Patag6nico se vincula a1 ciclo magmatic0 Patagonidico en el que se reconocen tres fases diastr6ficas: una inicial de caracter tensional que produce un extenso vulcan i s m~, una oroghnica que controla el emplazamiento del Batolito Andino y una p6stuma posiblemente tensional en el Senoniano .A1 este de la Cordillera se encuentran una serie de plateaux de basaltos alcalinos, correspondientes a diferentes pulsos de actividad durante el Eoceno, Mioceno superior, Plioceno y tambihn durante el Cuaternario. Un analisis detallado de estos eventos puede leerse en Ramoset al. (19821, Ramos & Kay (1992) y Kay (2002), entre otros.En la actualidad el magmatismo estk representado por varios aparatos volc~nicos, el mas pr6ximo a la zona objeto de este estudio es el Volcan Lautaro ubicado en el Hielo Patagbnico, en territorio chileno, a la latitud del lago San Martin.En la Patagonia extraandina un importante vulcanismo basico, plateaux basalticos, de asociaci6n alcalina, comenz6 en el Cretacico superior con un mfiximo en el Mioceno superior e inferior. El magma original estaria localizado a grandes profundidades en el inanto, en contraposici6n a 10s basaltos que estan cerca de la cordillera, de una asociacibn tholeitica v alcalina, 10s cuales se habrian originado a profundidades mas someras. Los datos de inclusiones ultramaficas y maficas sugieren que 10s basaltos, aun 10s u...

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Magmatic evolution of the Austral Patagonian Andes

Cited by 87 publications

References 27 publications

U-Pb zircon constraints on the age of the Cretaceous Mata Amarilla Formation, Southern Patagonia, Argentina: its relationship with the evolution of the Austral Basin

U-Pb zircon constraints on the age of the Cretaceous Mata Amarilla Formation, Southern Patagonia, Argentina: its relationship with the evolution of the Austral Basin

Paleomagnetism of the late Cenozoic basalts from northern Patagonia

Fitz Roy granite characterization Province of Santa Cruz, Argentina

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