Quaternary volcanic activity of Hudson and Lautaro volcanoes, Chilean Patagonia: New constraints from K-Ar ages
Actividad volcanica cuaternaria de los volcanes Hudson y Lautaro, Patagonia chilena: nuevas edades K-Ar.
| dc.contributor | en-US | |
| dc.contributor | es-ES | |
| dc.creator | Orihashi, Yuji | |
| dc.creator | Naranjo, Jose A. | |
| dc.creator | Motoki, Akihisa | |
| dc.creator | Sumino, Hirochika | |
| dc.creator | Hirata, Daiji | |
| dc.creator | Anma, Ryo | |
| dc.creator | Nagao, Keisuke | |
| dc.date | 2010-06-29 | |
| dc.identifier | http://www.andeangeology.cl/index.php/revista1/article/view/V31n2-a02 | |
| dc.identifier | 10.5027/andgeoV31n2-a02 | |
| dc.description | Twenty-nine K-Ar ages for lavas and juvenile ejecta obtained from Hudson volcano in the southern end of the Southern Volcanic Zone and Lautaro volcano in the northern end of the Austral Volcanic Zone, which are separated by a 350 km-long volcanic gap near the Chile ridge subduction zone, were determined using unspiked method that has significant sensitivity for dating young rocks (<0.1 Ma). It is newly revealed that Hudson is a significantly long-lived volcano; its activity started at ca. 1.0 Ma and continues to the Recent. The Hudson volcano has a well-preserved summit caldera complex of approximately 10 km in diameter, previously thought to be formed by a single event during the Holocene, perhaps at 6700 years BP. Our results for the K-Ar dating, however, indicate that the northeastern and southeastern flanks of the volcano formed at different times; formation of NE flank preceded that of SE flank. Aero-photographic observations indicate the presence of two or even three caldera rims. These data suggest that the Hudson volcano had a complex evolution, superimposing or partially nesting calderas rather than a simple caldera. The activity of the Lautaro volcano, began at ca. 0.17 Ma and has continued to the Recent, as it is indicated by our K-Ar first results. Though Lautaro volcano is a relatively large stratovolcano for Chilean Patagonia, the chemical and radiometric results indicate a narrow range in its variability when compared with those of the Hudson volcano. These narrow compositional and geochronological ranges suggest that the Lautaro volcano developed from a homogeneous magma chamber produced by slab melting during the late Quaternary, assuming that the sampled part of this heavily ice-mantled volcano, spans its full lifetime. | en-US |
| dc.description | Mediante el uso del metodo K-Ar 'unspiked', el cual tiene notable sensibilidad para datar rocas jovenes (<0,1 Ma), se obtuvieron 29 edades radiometricas de lavas y piroclastos juveniles de los volcanes Hudson y Lautaro. Separados por un 'gap' volcanico de 350 km, cercano a la zona de subduccion de la dorsal de Chile, estos volcanes se ubican en los extremos sur de los Andes del Sur y norte de los Andes Australes, respectivamente. Estos datos indican que el volcan Hudson ha tenido un tiempo de desarrollo notablemente largo desde hace 1 Ma hasta el presente. Esta formado por una caldera bien conservada de aproximadamente 10 km de diametro, la cual, se pensaba habia sido formada por solo un evento eruptivo, probablemente a los 6700 años AP. Sin embargo, nuestros resultados revelan que los flancos nororiental y suroriental del volcan se originaron durante epocas diferentes, siendo mas antigua la formacion de la estructura norte. Observaciones fotogeologicas indican la presencia de dos o, eventualmente, tres bordes de caldera. Estos antecedentes indican que el volcan Hudson tuvo una evolucion mas bien compleja consistente en la sobreimposicion o anidamiento parcial de estructuras, mas que la formacion de una caldera simple. De acuerdo con los primeros resultados de los presentes autores, en el caso del volcan Lautaro, la actividad que comenzo hace aproximadamente 0,17 Ma continua hasta el presente. Aunque es un volcan relativamente grande comparado con otros de la Patagonia chilena, muestra un intervalo de edad y composicion notablemente menores que el volcan Hudson. Asumiendo que el muestreo es representativo del espectro evolutivo completo del Lautaro, el cual esta casi totalmente cubierto por hielo, estas caracteristicas sugieren que este volcan se ha desarrollado durante un periodo corto en el Cuaternario tardio, a partir de una camara magmatica homogenea alimentada por la fusion de la placa. | es-ES |
| 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/V31n2-a02/603 | |
| dc.relation | http://www.andeangeology.cl/index.php/revista1/article/view/V31n2-a02/html | |
| dc.source | Andean Geology; Vol 31, No 2 (2004); 207-224 | es-ES |
| dc.source | Andean Geology; Vol 31, No 2 (2004); 207-224 | en-US |
| dc.source | 0718-7106 | |
| dc.source | 0718-7092 | |
| dc.title | Quaternary volcanic activity of Hudson and Lautaro volcanoes, Chilean Patagonia: New constraints from K-Ar ages | en-US |
| dc.title | Actividad volcanica cuaternaria de los volcanes Hudson y Lautaro, Patagonia chilena: nuevas edades K-Ar. | es-ES |
| 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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