El Rojo Norte

Coordinates: 18°28′S 69°12′W / 18.467°S 69.200°W / -18.467; -69.200[1] El Rojo Norte is a cinder cone in the Andes,[2] constructed on top of volcano debris in the Lauca basin.[1]

The cone is 150 metres (490 ft) high[3] and 300 metres (980 ft) wide at its foot. Its profile has been reduced by erosion;[1] the cone sits on an andesitic mound.[4] A lava flow containing mafic andesite is associated with the cone.[3] Phreatomagmatic deposits are also found.[4]

The cone is formed by reddish scoria.[1] Its rocks are basaltic andesite. It was erupted 3.1 ± 0.2 million years ago on the basis of potassium-argon dating.[2] 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.[3]

References

  1. 1 2 3 4 Wigger, edited by Klaus-Joachim Reutter, Ekkehard Scheuber, Peter J. (1994). Tectonics of the Southern Central Andes Structure and Evolution of an Active Continental Margin. Berlin, Heidelberg: Springer Berlin Heidelberg. p. 81. ISBN 978-3-642-77353-2. Retrieved 2 April 2016.
  2. 1 2 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. doi:10.1016/j.jsames.2004.06.008.
  3. 1 2 3 Gerhard Wörner; Konrad Hammerschmidt; Friedhelm Henjes-Kunst; Judith Lezaun; Hans Wilke (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). doi:10.4067/S0716-02082000000200004. ISSN 0716-0208 – via SciELO.
  4. 1 2 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). doi:10.1007/BF00240567.


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