| 词条 | Tumisa |
| 释义 |
|coordinates = {{coord|23|28|S|67|49|W|type:mountain_scale:100000|format=dms|display=inline,title}} |elevation_m = 5658|elevation_ref = [1]|coordinates_ref = [1]|other_name = Cerro Tumisa|last_eruption = 500,000 years ago|age = Pleistocene|volcanic_belt = Central Volcanic Zone|type = Stratovolcano|range = Andes|map_caption = }}Tumisa (also known as {{lang|es|Cerro Tumisa}}) is a Pleistocene stratovolcano in the Andes. Located east of the Salar de Atacama, it is part of the Central Volcanic Zone, which since the Miocene has been subject to extensive andesitic/dacitic effusive activity and ignimbrite eruptions. The basement on which Tumisa is built includes Paleozoic rocks and more recent volcanic products of the Lejia volcano and the Atana and Patao ignimbrites.[3] Block flows, lava flows, lava domes and some ignimbrites of pumiceous composition form this composite volcano. More than six lava domes and two major cones are part of this system and surrounded by a pyroclastic apron,[5] which covers a surface area of {{convert|300|km2}} and is formed from many pyroclastic flows with a total volume of {{convert|21|km3}}. The pyroclastic flows contain pumice and large blocks, some of which show signs of deformation when they were still hot. The lava domes and lavas are grouped in three units. Presumably, the activity of Tumisa started with explosive eruptions that generated the ignimbrite apron, later degassed magma formed the lava domes and lava flows.[3] Dating of the volcano indicates that it becomes younger with higher altitude, a pattern that may be explained either by a shift in the magmatic system or a progressive downslope sliding of the volcano during its history at a speed of {{convert|0.5|-|2|cm/yr}}. This interpretation is supported by the drainage patterns of the volcano, with channels bending outwards and curving towards the west. These channels possibly formed over faults of the slipping volcano.[5] Valleys ({{lang|es|quebradas}}) were excavated less than one million years ago during the glacial stages in Tumisa's northern flank. Moraines are also found.[8] The volcano has erupted dacitic lavas containing andesitic mafic inclusions. These inclusions resemble those from the Soncor flow of neighbouring Lascar to the northeast. Some rocks may have been influenced by the interaction with calcium carbonate in the magma chambers.[9] Hornblende crystals with dimensions of {{convert|5|-|10|mm}} and megacrysts of feldspar with dimensions of up to {{convert|1.5|cm}} are also present.[8] The textures of the products suggest that magma mixing occurred during activity.[11] The dacites have a white porphyritic appearance. The dome complex is dated 2.5-0.5 mya and the associated pyroclastics 1.5-0.5 mya and constructed on Tertiary ignimbrites.[12] One date of 1.2±0.6 million years was obtained from the Las Mulas dome.[3] The complex is of Pleistocene age. Later, hydrothermal alteration occurred.[3] A fault with probably postglacial activity crosses the Laguna Lejia and is associated with Tumisa, connecting Tumisa with a basaltic maar and an isolated lava dome. It runs in northwest-southeast direction and crosses Lejia on its southern margin.[16] Tumisa and its neighbouring mountains Lausa, Chiliques, Ipira and Miniques are identified by the inhabitants of Socaire to be part of a giant human left hand with dimensions of {{convert|40|x|30|km}} on the eastern horizon.[17] References1. ^1 {{cite journal|last1=MATTHEWS|first1=S. J.|last2=JONES|first2=A. P.|last3=GARDEWEG|first3=M. C.|title=Lascar Volcano, Northern Chile; Evidence for Steady-State Disequilibrium|journal=Journal of Petrology|date=1 April 1994|volume=35|issue=2|pages=401–432|doi=10.1093/petrology/35.2.401|url=http://petrology.oxfordjournals.org/content/35/2/401.abstract|accessdate=11 October 2015}} [1][2][3][4][5][6][7][8]2. ^1 {{cite web|last1=Matthews|first1=Steve|last2=Vita-Finzi|first2=Claudio|title=Neotectonics at Laguna Lejia, Atacama Desert, Northern Chile|url=http://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_6/colloques2/38384.pdf|website=Horizon pleins textes|publisher=Institut de recherche pour le développement (IRD)|accessdate=11 October 2015|archiveurl=https://web.archive.org/web/20061126233940/http://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_6/colloques2/38384.pdf|archivedate=26 November 2006|date=23 September 1993}} 3. ^1 {{cite journal|last1=Calder|first1=E.S.|last2=Sparks|first2=R.S.J.|last3=Gardeweg|first3=M.C.|title=Erosion, transport and segregation of pumice and lithic clasts in pyroclastic flows inferred from ignimbrite at Lascar Volcano, Chile|journal=Journal of Volcanology and Geothermal Research|date=December 2000|volume=104|issue=1–4|pages=201–235|doi=10.1016/S0377-0273(00)00207-9}} 4. ^1 2 {{cite journal|last1=Wooller|first1=Luke|last2=van Wyk de Vries|first2=Benjamin|last3=Murray|first3=John B.|last4=Rymer|first4=Hazel|last5=Meyer|first5=Stephanie|title=Volcano spreading controlled by dipping substrata|journal=Geology|date=2004|volume=32|issue=7|pages=573|doi=10.1130/G20472.1}} 5. ^1 2 {{cite journal|last1=GARDEWEG|first1=M. C.|last2=SPARKS|first2=R. S. J.|last3=MATTHEWS|first3=S. J.|title=Evolution of Lascar Volcano, Northern Chile|journal=Journal of the Geological Society|date=1 February 1998|volume=155|issue=1|pages=89–104|doi=10.1144/gsjgs.155.1.0089|url=http://jgs.lyellcollection.org/content/155/1/89.short|accessdate=11 October 2015}} 6. ^1 {{cite journal|last1=MATTHEWS|first1=S. J.|last2=JONES|first2=A. P.|last3=BRISTOW|first3=C. S.|title=A simple magma-mixing model for sulphur behaviour in calc-alkaline volcanic rocks: mineralogical evidence from Mount Pinatubo 1991 eruption|journal=Journal of the Geological Society|date=1 December 1992|volume=149|issue=6|pages=863–866|doi=10.1144/gsjgs.149.6.0863|url=http://jgs.lyellcollection.org/content/149/6/863.abstract|accessdate=11 October 2015}} 7. ^1 {{cite journal|last1=Moyano|first1=Ricardo|last2=Uribe|first2=Carlos|title=EL VOLCÁN CHILIQUES Y EL "MORAR-EN-EL-MUNDO" DE UNA COMUNIDAD ATACAMEÑA DEL NORTE DE CHILE|journal=Estudios atacameños|date=2012|issue=43|pages=187–208|doi=10.4067/S0718-10432012000100010|language=es|issn=0718-1043}} 8. ^1 2 {{cite book|last1=Gonzalez-Ferran|first1=Oscar|title=Volcanes de Chile|date=1994|publisher=Instituto geografico militar|location=Santiago, Chile|isbn=978-9562020541|page=183|edition=1.|url=https://books.google.ch/books?id=m2hdAAAAMAAJ|accessdate=11 October 2015}} 9. ^1 2 3 4 {{cite web|last1=Gardeweg|first1=Moyra P|title=Petrografia y geoquimica del complejo volcánico Tumisa, Altiplano de Antofagasta, Andes del Norte de Chile|url=http://biblioserver.sernageomin.cl/opac/DataFiles/5141ppI183_I208.pdf|website=biblioserver.sernageomin.cl|publisher=SERNAGEOMIN|accessdate=11 October 2015|archiveurl=https://web.archive.org/web/20151011132332/http://biblioserver.sernageomin.cl/opac/DataFiles/5141ppI183_I208.pdf|archivedate=11 October 2015|location=Santiago|language=es|date=1988}} [9]}} External links
2 : Stratovolcanoes of Chile|Pleistocene volcanoes |
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