El Rojo Norte
18°28′S 69°12′W / 18.467°S 69.200°W
El Rojo Norte is a cinder cone in the Andes, constructed on top of volcano debris in the Lauca basin.
The cone is 150 metres (490 ft) high and 300 metres (980 ft) wide at its foot. Its profile has been reduced by erosion; the cone sits on an andesitic mound. A lava flow containing mafic andesite is associated with the cone. Phreatomagmatic deposits are also found.
The cone is formed by reddish scoria. Its rocks are basaltic andesite. It was erupted 3.1 ± 0.2 million years ago on the basis of potassium-argon dating. Other dates are 3.05 ± 0.22, 3.35 ± 0.16 and 2.34 ± 0.16 mya. Which age is correct is unclear, but the cone is partly buried by the 2.72 mya old Lauca-Pérez ignimbrite indicating that it's older than this ignimbrite.
References
- ^ Wigger, edited by Klaus-Joachim Reutter, Ekkehard Scheuber, Peter J. (1994). "Large- and Fine-Scale Geochemical Variations Along the Andean Arc of Northern Chile (17.5°– 22°S)". Tectonics of the Southern Central Andes Structure and Evolution of an Active Continental Margin. Berlin, Heidelberg: Springer Berlin Heidelberg. p. 81. doi:10.1007/978-3-642-77353-2_5. ISBN 978-3-642-77353-2.
{{cite book}}:|first1=has generic name (help)CS1 maint: multiple names: authors list (link) - ^ Charrier, Reynaldo; Chávez, Alvaro N.; Elgueta, Sara; Hérail, Gérard; Flynn, John J.; Croft, Darin A.; Wyss, André R.; Riquelme, Rodrigo; García, Marcelo (May 2005). "Rapid tectonic and paleogeographic evolution associated with the development of the Chucal anticline and the Chucal-Lauca Basin in the Altiplano of Arica, northern Chile". Journal of South American Earth Sciences. 19 (1): 35–54. Bibcode:2005JSAES..19...35C. doi:10.1016/j.jsames.2004.06.008.
- ^ Wörner, Gerhard; Hammerschmidt, Konrad; Henjes-Kunst, Friedhelm; Lezaun, Judith; Wilke, Hans (December 2000). "Geochronology (40Ar/39Ar, K-Ar and He-exposure ages) of Cenozoic magmatic rocks from Northern Chile (18-22°S): implications for magmatism and tectonic evolution of the central Andes". Revista Geológica de Chile. 27 (2): 205–240.
- ^ Kött, A.; Gaupp, R.; Wörner, G. (December 1995). "Miocene to recent history of the western Altiplano in northern Chile revealed by lacustrine sediments of the Lauca basin (18°15'-18°40' S/69°30'-69°05' W)". Geologische Rundschau. 84 (4): 770. Bibcode:1995GeoRu..84..770K. doi:10.1007/BF00240567. S2CID 129479890.
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