Coranzulí (caldera)

Coranzuli is a back-arc caldera in the Andes,[2]:241 related to the Altiplano-Puna volcanic complex.[3]

It formed along the Lipez geological lineament about 6.6 million years ago.[4] Volcanic ash samples found in the Coastal Cordillera of Chile may come from this volcano.[5] The Rachaite (23°00′S 66°5′W[1]:85) stratovolcano is located close to the caldera.[2]:240 The formation of this caldera has been influenced by a number of local fault systems,[6]:132 the Coyaguayama and Rachaite lineaments.[7]:1270

Marine sediments of Ordovician age with some later volcanic intrusions form the basement together with Cretaceous-Eocene sediments. Three cycles of volcanic activity preceding the Coranzuli ignimbrite have been identified.[8]:251 The Coranzuli system is part of a Late Miocene volcanic episode that also includes Aguas Calientes, Cerro Panizos and the Toconquis ignimbrite of Galan.[9]

The Morro Grande Formation may have originated by volcanic activity in the area of Cerro Coranzuli.[8]:251 c. 6.8 to 6.4 million years ago, this caldera erupted the Coranzuli ignimbrites. They have a total volume of c. 650 cubic kilometres (160 cu mi).[2]:241 They are named in order from oldest to youngest Abra Grande ignimbrite, Potreros ignimbrite, Las Termas ignimbrites 1 and 2,[1]:85 and a smaller one Corral de Sangre. They are most likely the products of the same eruption.[7]:1270 The Coranzuli Ignimbrite was erupted in three distinct flows, the last one is the largest one and has the highest matrix component. This ignimbrite is of rhyodacitic composition.[8]:258 The Las Termas Ignimbrite contains pumice and is highly welded and crystalline.[6]:131 A 5 kilometres (3.1 mi) wide caldera was left by the eruption that formed this ignimbrite[6]:132 and postcaldera volcanism generated three thick dacitic lava flows within it.[7]:1272 The Cerro Coranzuli lava dome was erupted subsequently.[8]:251 A major seismic velocity anomaly is found beneath Coranzuli volcano.[2]:245

References
  1. Kay, Suzanne Mahlburg; Coira, Beatriz L.; Caffe, Pablo J.; Chen, Chang-Hwa (December 2010). "Regional chemical diversity, crustal and mantle sources and evolution of central Andean Puna plateau ignimbrites". Journal of Volcanology and Geothermal Research. 198 (1–2): 81–111. doi:10.1016/j.jvolgeores.2010.08.013.
  2. Kay, S. M.; Coira, B. L (1 June 2009). Shallowing and steepening subduction zones, continental lithospheric loss, magmatism, and crustal flow under the Central Andean Altiplano-Puna Plateau. Geological Society of America Memoirs. 204. pp. 229–259. doi:10.1130/2009.1204(11). ISBN 9780813712048.
  3. Zandt, G.; Leidig, M.; Chmielowski, J.; Baumont, D.; Yuan, X. (March 2003). "Seismic Detection and Characterization of the Altiplano-Puna Magma Body, Central Andes". Pure and Applied Geophysics. 160 (3): 797. doi:10.1007/PL00012557.
  4. Caffe, P.J.; Soler, M.M.; Coira, B.L.; Onoe, A.T.; Cordani, U.G. (June 2008). "The Granada ignimbrite: A compound pyroclastic unit and its relationship with Upper Miocene caldera volcanism in the northern Puna". Journal of South American Earth Sciences. 25 (4): 482. doi:10.1016/j.jsames.2007.10.004.
  5. Breitkreuz, Christoph; de Silva, Shanaka L.; Wilke, Hans G.; Pfänder, Jörg A.; Renno, Axel D. (January 2014). "Neogene to Quaternary ash deposits in the Coastal Cordillera in northern Chile: Distal ashes from supereruptions in the Central Andes". Journal of Volcanology and Geothermal Research. 269: 79. doi:10.1016/j.jvolgeores.2013.11.001.
  6. Kay, Suzanne Mahlburg; Coira, Beatriz; Mpodozis, Constantino (2008). GSA Field Guide 13: Field Trip Guides to the Backbone of the Americas in the Southern and Central Andes: Ridge Collision, Shallow Subduction, and Plateau Uplift. 13. pp. 117–181. doi:10.1130/2008.0013(05). ISBN 978-0-8137-0013-7 – via https://www.researchgate.net/profile/B_Coira/publication/279723669_Field_trip_guide_Neogene_evolution_of_the_central_Andean_Puna_plateau_and_southern_Central_Volcanic_Zone/links/55f2234508aef559dc49341b/Field-trip-guide-Neogene-evolution-of-the-central-Andean-Puna-plateau-and-southern-Central-Volcanic-Zone.pdf.
  7. Seggiaro, R.; Guzmán, S.; J. Martí, J.; C. Montero, C.; López, E. (2014). Rocha, Rogério; Pais, João; Kullberg, José Carlos; Finney, Stanley (eds.). STRATI 2013 : first International Congress on Stratigraphy At the Cutting Edge of Stratigraphy (Aufl. 2014 ed.). Cham: Springer International Publishing. doi:10.1007/978-3-319-04364-7_243. ISBN 978-3-319-04364-7.
  8. Leroy, Jacques L.; George-Aniel, Brigitte (April 1992). "Volcanism and uranium mineralizations: the concept of source rock and concentration mechanism". Journal of Volcanology and Geothermal Research. 50 (3): 247–272. doi:10.1016/0377-0273(92)90096-V.
  9. Matteini, M; Mazzuoli, R; Omarini, R; Cas, R; Maas, R (November 2002). "Geodynamical evolution of Central Andes at 24°S as inferred by magma composition along the Calama–Olacapato–El Toro transversal volcanic belt". Journal of Volcanology and Geothermal Research. 118 (1–2): 208. doi:10.1016/S0377-0273(02)00257-3.
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