TulTul, Del Medio and Pocitos
24°10′S 67°03′W / 24.167°S 67.050°W[1] TulTul, Del Medio and Pocitos are three volcanoes in Argentina. Small Inka shrines have been found on their summits.[2]
Since the Jurassic, subduction off the western margin of South America has generated volcanism, which after starting in the Cordillera de la Costa now occurs in the Andes. Since the Oligocene, the Puna has been volcanically active as well. There, some stratovolcanoes including TulTul, Del Medio and Pocitos are aligned on the Calama-Olacapato-El Toro fault which cuts across the plateau in southeast direction.[1]
TulTul, Del Medio and Pocitos are constructed by andesite and dacite and form a 35 kilometres (22 mi) long alignment. Del Medio and Pocitos both feature traces of their southern flank collapsing, and both have a summit caldera 3.5 kilometres (2.2 mi) and 3 kilometres (1.9 mi) wide respectively. Tul Tul had a central vent which formed andesitic lava flows and later above these lava flows dacitic domes.[1]
The volcanoes were active 8 to 6 million years ago, during the Miocene. Lava domes were emplaced on all three volcanoes late in their history.[1] The magmas that constructed these volcanoes appear to have originated in the lower crust from a garnet-bearing precursor.[3] Moraines developed at elevations exceeding 3,900 metres (12,800 ft) elevation on Del Medio and Pocitos, consisting of c. 2 metres (6 ft 7 in) features on the walls of a cirque and two lateral moraines downvalley.[4] These moraines formed before the last glacial maximum, but during wet periods in the Salar de Uyuni.[5]
References
[edit]- ^ a b c d Matteini, M.; Mazzuoli, R.; Omarini, R.; Cas, R.; Maas, R. (February 2002). "The geochemical variations of the upper cenozoic volcanism along the Calama–Olacapato–El Toro transversal fault system in central Andes (~24°S): petrogenetic and geodynamic implications". Tectonophysics. 345 (1–4): 211–227. Bibcode:2002Tectp.345..211M. doi:10.1016/S0040-1951(01)00214-1. ISSN 0040-1951.
- ^ Ceruti, Constanza (18 August 2018). "Inca Mountaintop Shrines and Glaciers". Journal of Glacial Archaeology. 3: 70–71. doi:10.1558/jga.34465. hdl:11336/129777. ISSN 2050-3407. S2CID 134141809.
- ^ Acocella, V.; Gioncada, A.; Omarini, R.; Riller, U.; Mazzuoli, R.; Vezzoli, L. (1 June 2011). "Tectonomagmatic characteristics of the back‐arc portion of the Calama–Olacapato–El Toro Fault Zone, Central Andes". Tectonics. 30 (3): n/a. Bibcode:2011Tecto..30.3005A. doi:10.1029/2010TC002854. hdl:11336/13093. ISSN 1944-9194. S2CID 129273472.
- ^ Luna, Lisa V.; Bookhagen, Bodo; Niedermann, Samuel; Rugel, Georg; Scharf, Andreas; Merchel, Silke (October 2018). "Glacial chronology and production rate cross-calibration of five cosmogenic nuclide and mineral systems from the southern Central Andean Plateau". Earth and Planetary Science Letters. 500: 243. Bibcode:2018E&PSL.500..242L. doi:10.1016/j.epsl.2018.07.034. ISSN 0012-821X. S2CID 134780354.
- ^ Luna, Lisa V.; Bookhagen, Bodo; Niedermann, Samuel; Rugel, Georg; Scharf, Andreas; Merchel, Silke (October 2018). "Glacial chronology and production rate cross-calibration of five cosmogenic nuclide and mineral systems from the southern Central Andean Plateau". Earth and Planetary Science Letters. 500: 249. Bibcode:2018E&PSL.500..242L. doi:10.1016/j.epsl.2018.07.034. ISSN 0012-821X. S2CID 134780354.
External links
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