| 词条 | Crater Basalt volcanic field |
| 释义 |
The field covers a surface area of {{convert|700|km2}} and a width of {{convert|60|km}}.[3] It presents monogenetic volcanoes and several shield volcanoes that have merged to form volcanic plateaus.[4] The tallest of these cones, Antitruz 1, is {{convert|88|m}} high.[3] Major cones in the field are Cerro Contreras, Cerro Fermín, Cerro Negro, Cerro Ventana, Cerro Volcán and Pinchuleu.[6] Of these Cerro Negro is the highest with {{convert|1344|m}} altitude. The field's products include lava and tephra.[8] In total 26 cones and 9 eruptive centres have generated {{convert|2.3|km3}} of eruption products. Volcanic cones are formed from spatter, which was still hot and liquid when falling down and fused together to form erosion-resistant spatter cones.[3] Lava flows in the area are pahoehoe that formed lava tubes, lava tumuli and "whaleback" structures.[10] They are between {{convert|1|-|10|m}} thick.[6] Cerro Fermín alone is the origin of six lava flows. Being {{convert|300|km}} east of the main arc,[3] it is part of the back-arc of the Andean Southern Volcanic Zone.[8] The Southern Volcanic Zone is formed by the subduction of the Nazca Plate beneath the South America plate at a pace of {{convert|9|cm/yr}} in the Peru-Chile Trench, {{convert|400|km}} west of Crater Basalt.[6] It developed within the {{convert|30|km}} wide Gastre graben that also contains salt pans.[3] This graben is part of a major fault system that extends from the Atlantic Ocean to the Pacific. Northeast of the field lies the Somuncura basaltic field of Oligocene-Miocene age and uncertain origin.[6] It was active between 600 and 340 ka.[8] Three stages of activity have been identified, one 1 mya, the second 0.6 mya and the third 0.3 mya.[3] Activity has migrated eastward during time.[6] Other estimates indicate Holocene activity,[1] supported by stratigraphic relationships of Cerro Ventana and Cerro Contreras lava flows with nearby river sediments.[6] The Holocene Tagua ash (<2712–2360 BP) may originate from the Crater Basalt volcanic field but there are geographical and petrological problems with this theory.[24] The shield volcanoes have formed basalt as eruption products.[4] Crater Basalt basalts include basanite and trachybasalts.[6] Incompatible elements and rare-earth elements are enriched in these lavas.[10] The volcanic rocks are derived from decompression melting of the asthenosphere, with garnet and lherzolite as precursors.[8] Dunite xenoliths are found within the erupted basalts.[4] References1. ^1 2 3 4 5 6 7 {{cite journal|last1=Massaferro|first1=Gabriela I.|last2=Haller|first2=Miguel J.|last3=D'Orazio|first3=Massimo|last4=Alric|first4=Viviana I.|title=Sub-recent volcanism in Northern Patagonia: A tectonomagmatic approach|journal=Journal of Volcanology and Geothermal Research|date=July 2006|volume=155|issue=3–4|pages=227–243|doi=10.1016/j.jvolgeores.2006.02.002}} [1][2][3][4][5][6][7]2. ^1 2 {{cite web|last1=Haller|first1=Miguel J.|title=Preliminary K - Ar g eochronolog y of Neogene back arc volcanism in Northern Patagonia, Argentina|url=https://www.researchgate.net/publication/281068196|website=researchgate.net|publisher=IA VCEI – CVS – IAS 3IMC Conference|accessdate=27 February 2016|location=Malargüe|date=2009}} 3. ^1 {{cite journal|last1=Németh|first1=K.|last2=Haller|first2=M. J.|last3=Martin|first3=U.|last4=Risso|first4=C.|last5=Massaferro|first5=G.|title=Morphology of lava tumuli from Mendoza (Argentina), Patagonia (Argentina), and Al-Haruj (Libya)|journal=Zeitschrift für Geomorphologie|date=1 June 2008|volume=52|issue=2|pages=181–194|doi=10.1127/0372-8854/2008/0052-0181}} 4. ^1 {{cite journal|last1=Watt|first1=Sebastian F.L.|last2=Pyle|first2=David M.|last3=Naranjo|first3=José A.|last4=Rosqvist|first4=Gunhild|last5=Mella|first5=Mauricio|last6=Mather|first6=Tamsin A.|last7=Moreno|first7=Hugo|author-link7=Hugo Moreno Roa|title=Holocene tephrochronology of the Hualaihue region (Andean southern volcanic zone, ∼42° S), southern Chile|journal=Quaternary International|date=December 2011|volume=246|issue=1–2|pages=324–343|doi=10.1016/j.quaint.2011.05.029}} 5. ^1 2 3 4 5 6 {{cite web|last1=Haller|first1=Miguel J.|last2=Meister|first2=Carlos M.|last3=Risso|first3=Corina|last4=Inbar|first4=Moshe|title=MORFOMETRÍA DEL CAMPO VOLCÁNICO DEL BASALTO CRÁTER, CHUBUT|url=http://www.gaea.org.ar/contribuciones/Contribuciones2013/Haller_Meister_Risso_Inbar_2013.pdf|website=gaea.org.ar|publisher=Sociedad Argentina de Estudios Geográficos|accessdate=27 February 2016|language=es}} 6. ^1 2 {{cite journal|last1=Fontijn|first1=Karen|last2=Lachowycz|first2=Stefan M.|last3=Rawson|first3=Harriet|last4=Pyle|first4=David M.|last5=Mather|first5=Tamsin A.|last6=Naranjo|first6=José A.|last7=Moreno-Roa|first7=Hugo|author-link7=Hugo Moreno Roa|title=Late Quaternary tephrostratigraphy of southern Chile and Argentina|journal=Quaternary Science Reviews|date=April 2014|volume=89|pages=70–84|doi=10.1016/j.quascirev.2014.02.007}} 7. ^1 2 3 4 {{cite journal|last1=Jacques|first1=G.|last2=Hoernle|first2=K.|last3=Gill|first3=J.|last4=Wehrmann|first4=H.|last5=Bindeman|first5=I.|last6=Lara|first6=Luis E.|title=Geochemical variations in the Central Southern Volcanic Zone, Chile (38–43°S): The role of fluids in generating arc magmas|journal=Chemical Geology|date=April 2014|volume=371|pages=27–45|doi=10.1016/j.chemgeo.2014.01.015}} 8. ^1 2 3 {{cite journal|last1=Massaferro|first1=Gabriela I.|last2=Haller|first2=Miguel J.|last3=Dostal|first3=Jarda|last4=Pécskay|first4=Zoltán|last5=Prez|first5=Horacio|last6=Meister|first6=Carlos|last7=Alric|first7=Viviana|title=Possible sources for monogenetic Pliocene–Quaternary basaltic volcanism in northern Patagonia|journal=Journal of South American Earth Sciences|date=November 2014|volume=55|pages=29–42|doi=10.1016/j.jsames.2014.07.001}} [8]}} 3 : Volcanoes of Chubut Province|Holocene volcanism|Volcanic fields |
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