Geocronologia (49Ar/39Ar, K-Ar y edades He de exposicion) de rocas cenozoicas del norte de Chile (18-22°S): implicancias para el magmatismo y la evolucion tectonica de los Andes centrales.
Geochronology (40Ar/39Ar, K-Ar and He-exposure ages) of Cenozoic magmatic rocks from Northern Chile (18-22°S): implications for magmatism and tectonic evolutionof the central Andes
| dc.contributor | en-US | |
| dc.contributor | es-ES | |
| dc.creator | Wörner, Gerhard | |
| dc.creator | Hammerschmidt, Konrad | |
| dc.creator | Henjes-Kunst, Friedhelm | |
| dc.creator | Lezaun, Judith | |
| dc.creator | Wilke, Hans | |
| dc.date | 2010-06-30 | |
| dc.identifier | http://www.andeangeology.cl/index.php/revista1/article/view/V27n2-a04 | |
| dc.identifier | 10.5027/andgeoV27n2-a04 | |
| dc.description | Las edades K-Ar y Ar/Ar de rocas magmaticas del norte de Chile (18-22°S) describen la duracion y extension de la evolucion magmatica terciaria y cuaternaria, y datan los eventos tectonicos mayores en esta region. Este trabajo resume nuevas edades K-Ar y Ar/Ar en minerales y roca total para intrusivos de la Precordillera, ignimbritas cenozoicas y estratovolcanes andesiticos del Escarpe Andino Occidental a los 18°S, y del frente volcanico. Las rocas intrusivas de la Precordillera (Quebrada Paguana, Quebrada Blanca, Quebrada Choja, Quebrada Guatacondo, Cerro Chandacolla) representan el sistema de arco magmatico cretacico a Eoceno, y dieron edades entre 45 y 35 Ma. Edades menores en rocas intrusivas son invariablemente causadas por alteracion deuterica. Las ignimbritas de las formaciones Putani y Oxaya dieron edades Ar-Ar en sanidina alrededor de 24.2 a 24.8 Ma y 22.8 a 19.4 Ma, respectivamente. Los estratovolcanes andesiticos que sobreyacen directamente a las ignimbritas de Oxaya al norte de la Cordillera Occidental, dieron edades de 20.3Ma (Cordon Quevilque) a 9.0 Ma (Cordon Margarita). Las muestras del Sistema de Arco Mioceno a Pleistoceno en el altiplano chileno que infrayacen a los volcanes del frente volcanico activo, han sido datadas entre 10.5 y ca. 3 Ma. Una ignimbrita de extensa distribucion areal puede ser corelacionada desde la cuenca de Lauca hasta la costa del Pacifico, y hacia el este con ocurencias vecinas a Perez. Dataciones repetidas por el metodo Ar-Ar en sanidina de la ignimbrita Lauca-Perez dieron resultados concordantes de 2.7±0.25 Ma, 2.72±0.01 Ma y 2.73±0.01 Ma. Rocas del arco actual (Cordillera Volcanica) dieron edades mas jovenes que 0. 9 Ma (volcanes, Irruputuncu, Olca, Aucanquilcha, Ollagüe, Porunita). Estos nuevos datos se usan para constrenir la estratigrafia miocena, los movimientos tectonicos y la cronologia de alzamiento y respuesta sedimentaria en el Escarpe Andino Occidental en el marco de la evolucion tectonica de los Andes centrales. | es-ES |
| dc.description | K-Ar and Ar/Ar ages from magmatic rocks of northern Chile (18-22°S) describe duration and extent of the Tertiary and Quaternary magmatic evolution and date major tectonic events in northernmost Chile. This paper summarizes new K-Ar and Ar-Ar mineral and whole rock ages for intrusive rocks from the Precordillera, Tertiary ignimbrites and andesitic stratovolcanoes from the Western Andean Escarpment at 18°S (WARP) and the volcanic front. Intrusive rocks of the Precordillera (Quebrada Paguana, Quebrada Blanca, Quebrada Choja, Quebrada Guatacondo, Cerro Chandacolla) represent the Cretaceous to Eocene magmatic arc system and gave ages between 45 and 35 Ma. Younger ages on intrusive rocks are invariably caused by deuteric alteration. Ignimbrites of the Putani and Oxaya formations gave Ar-Ar sanidine ages around 24.2 to 24.8 Ma and 22.8 to 19.4 Ma, respectively. Andesitic stratovolcanoes, which directly overlie Oxaya ignimbrites east of the Western Cordillera gave ages of 20.3 Ma (Cordon Quevilque) to 9.0 Ma (Cerro Margarita). Samples from the Miocene to Pleistocene arc system on the Chilean Altiplano underlying the volcanoes of the active volcanic front have been dated between 10.5 to ~3 Ma. A widespread ignimbrite can be correlated from the Lauca basin to the Pacific coast and to the east to occurrences of near Pérez. Repeated Ar-Ar sanidine dating of the Lauca-Pérez-ignimbrite resulted in highly concordant ages of 2.71±0.25 Ma, 2.72 Ma±0.01 Ma, and 2.73±0.11 Ma. Rocks from the active chain (Volcanic Cordillera) gave ages younger than 0.9 Ma (Volcán Irruputuncu, Volcán Olca, Volcán Aucanquilcha, Volcán Ollagüe, Volcán Poruñita). These new data are used to constrain Miocene stratigraphy and tectonic movements as well as the timing of uplift and sedimentary response at the Western Andean Escarpment within the framework of the tectonic evolution of the Central Andes. | en-US |
| dc.format | application/pdf | |
| dc.format | text/html | |
| dc.language | eng | |
| dc.publisher | Servicio Nacional de Geología y Minería | en-US |
| dc.relation | http://www.andeangeology.cl/index.php/revista1/article/view/V27n2-a04/707 | |
| dc.relation | http://www.andeangeology.cl/index.php/revista1/article/view/V27n2-a04/html | |
| dc.source | Andean Geology; Vol 27, No 2 (2000); 205-240 | es-ES |
| dc.source | Andean Geology; Vol 27, No 2 (2000); 205-240 | en-US |
| dc.source | 0718-7106 | |
| dc.source | 0718-7092 | |
| dc.title | Geocronologia (49Ar/39Ar, K-Ar y edades He de exposicion) de rocas cenozoicas del norte de Chile (18-22°S): implicancias para el magmatismo y la evolucion tectonica de los Andes centrales. | es-ES |
| dc.title | Geochronology (40Ar/39Ar, K-Ar and He-exposure ages) of Cenozoic magmatic rocks from Northern Chile (18-22°S): implications for magmatism and tectonic evolutionof the central Andes | en-US |
| dc.type | info:eu-repo/semantics/article | |
| dc.type | info:eu-repo/semantics/publishedVersion | |
| dc.type | es-ES | |
| dc.type | en-US |
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Andean Geology
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