Leon Muerto
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25°57′S 68°28′W / 25.950°S 68.467°W[1] Leon Muerto is a 4,799 metres (15,745 ft) high volcano in Chile.[1]
The Central Chilean Andes have an arid climate since the Miocene. Thus, a number of volcanic centres going back as far as 25 million years are well preserved.[2] Geologically, this area belongs to the Central Volcanic Zone, a volcanic belt in the Andes, whose magmas are heavily influenced by the thick crust of the area.[1]
Leon Muerto is a deeply eroded volcano with a radial symmetric structure on the border between Argentina and Chile. It covers a surface of 80 square kilometres (31 sq mi).[1] It was formed between 25 and 17 million years ago and has a volume of 19 cubic kilometres (4.6 cu mi). The crust beneath Leon Muerto has an average thickness of 60 kilometres (37 mi).[2] Better dates obtained on Leon Muerto by potassium-argon dating indicate an age of 19,900,000 ± 800,000 years ago.[1] It is among the oldest centres in the area[3] and parts of its subvolcanic structure are exposed.[4]
Erosion has exposed much of the structure of Leon Muerto. It includes lava flows 2–3 kilometres (1.2–1.9 mi) long, lapilli and tephra. Most of the rocks are basaltic andesite, dacite is also present in the central parts of the volcano and aluminum-rich basalt has also been found. Some lava flows contain olivine. The magmas that formed the volcano are partially evolved magmas, with their formation influenced by the crust.[1] These lavas are considered to be backarc lavas and resemble these of volcanoes farther south.[3]
A number of ignimbrites are found in the territory, one of them named Leon Muerto is found southwest of the volcano.[5] This ignimbrite is 5 million years old.[6]
References
[edit]- ^ a b c d e f Trumbull, R.B; Wittenbrink, R; Hahne, K; Emmermann, R; Büsch, W; Gerstenberger, H; Siebel, W (March 1999). "Evidence for Late Miocene to Recent contamination of arc andesites by crustal melts in the Chilean Andes (25–26°S) and its geodynamic implications". Journal of South American Earth Sciences. 12 (2): 135–155. doi:10.1016/S0895-9811(99)00011-5.
- ^ a b Villa, Victor; Naranjo, José Antonio (October 2015). "Morfometría de edificios volcánicos del Cenozóico Superior entre los 25º y 26º S, Chile". ResearchGate (in Spanish). La Serena: XIV Congreso Geológico Chileno. Retrieved 13 November 2016.
- ^ a b Kay, Suzanne Mahlburg; Mpodozis, Constantino; Gardeweg, Moyra (2014). "Magma sources and tectonic setting of Central Andean andesites (25.5–28°S) related to crustal thickening, forearc subduction erosion and delamination". Geological Society, London, Special Publications. 385 (1): 303–334. doi:10.1144/SP385.11.
- ^ Grosse, Pablo; Guzmán, Silvina; Petrinovic, I. (2017). Volcanes compuestos cenozoicos del noroeste argentino. Ciencias de la Tierra y Recursos Naturales del NOA (Muruaga, C.; Grosse, P (2017). p. 495 – via ResearchGate.
- ^ Schnurr, W.B.W.; Trumbull, R.B.; Clavero, J.; Hahne, K.; Siebel, W.; Gardeweg, M. (September 2007). "Twenty-five million years of silicic volcanism in the southern central volcanic zone of the Andes: Geochemistry and magma genesis of ignimbrites from 25 to 27 °S, 67 to 72 °W" (PDF). Journal of Volcanology and Geothermal Research. 166 (1): 22. doi:10.1016/j.jvolgeores.2007.06.005.
- ^ Schnurr, W.B.W.; Trumbull, R.B.; Clavero, J.; Hahne, K.; Siebel, W.; Gardeweg, M. (September 2007). "Twenty-five million years of silicic volcanism in the southern central volcanic zone of the Andes: Geochemistry and magma genesis of ignimbrites from 25 to 27 °S, 67 to 72 °W" (PDF). Journal of Volcanology and Geothermal Research. 166 (1): 21. doi:10.1016/j.jvolgeores.2007.06.005.