Eruptive history of Chimborazo volcano (Ecuador) : a large, ice-capped and hazardous compound volcano in the Northern Andes
New fieldwork, radiometric and whole-rock chemical data permit the reconstruction of the main eruptive stages of the Chimborazo compound volcano, the highest summit of the Northern Andes. Chimborazo is composed of three successive edifices. The Basal Edifice (CH-I) was active from similar to 120 to...
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ftird:oai:ird.fr:fdi:010055831 2023-05-15T16:38:24+02:00 Eruptive history of Chimborazo volcano (Ecuador) : a large, ice-capped and hazardous compound volcano in the Northern Andes Samaniego, Pablo Barba, D. Robin, Claude Fornari, Michel Bernard, Benjamin 2012 http://www.documentation.ird.fr/hor/fdi:010055831 EN eng http://www.documentation.ird.fr/hor/fdi:010055831 oai:ird.fr:fdi:010055831 Samaniego Pablo, Barba D., Robin Claude, Fornari Michel, Bernard Benjamin. Eruptive history of Chimborazo volcano (Ecuador) : a large, ice-capped and hazardous compound volcano in the Northern Andes. Journal of Volcanology and Geothermal Research, 2012, 221, p. 33-51. Chimborazo Andean volcanism Late Pleistocene Eruptive rates Volcanic hazards Ar-40-Ar-39 geochronology text 2012 ftird 2020-08-21T06:55:27Z New fieldwork, radiometric and whole-rock chemical data permit the reconstruction of the main eruptive stages of the Chimborazo compound volcano, the highest summit of the Northern Andes. Chimborazo is composed of three successive edifices. The Basal Edifice (CH-I) was active from similar to 120 to 60 ka and resulted in a large, mostly effusive edifice which was built up during two stages of cone-building, terminating with the formation of a dome complex. This edifice was affected by a huge sector collapse around 65-60 ka which produced a major debris avalanche that spread out into the Riobamba basin, covering about 280 km(2) with an average thickness of 40 m and a total volume of similar to 10-12 km(3). After the emplacement of the Riobamba debris avalanche, eruptive activity resumed at the eastern outlet of the avalanche scar and was responsible for the construction of a less voluminous, Intermediary Edifice (CH-II), whose current remnants are the Politecnica and Martinez peaks. This edifice developed from 60 to 35 ka. Lastly, eruptive activity shifted to the west, leading to the construction of the morphologically well-preserved Young Cone (CH-Ill) which currently forms the highest summit (Whymper). The average eruptive rate of Chimborazo volcano is 0.5-0.7 km(3)/ka. However, looking at the three successive edifices individually, we estimate that there has been a progressive decrease in magma output rate from the Basal Edifice (0.7-1.0 km(3)/ka), through the Intermediary Edifice (0.4-0.7 km(3)/ka) to the Young Cone (similar to 0.1 km(3)/ka). However, during the main cone-building stages, the peak eruption rates are markedly higher, indicating significant variations in the magma output rate during the lifespan of this arc volcano. During the Holocene, the Chimborazo eruptive activity consisted of small-volume explosive events that occurred at quite regular intervals, between about 8000 and 1000 yr ago. Since the last eruption occurred between the early part of the 5th century and the end of the 7th century, and the average time interval between the events is about 1000 yr. Chimborazo must be considered as a potentially active volcano. The presence of a thick ice cap covering the summit, its steep flanks and its position above the populated lowland area of Riobamba and Ambato, are factors that result in a high potential risk.(C) 2012 Elsevier B.V. All rights reserved. Text Ice cap IRD (Institute de recherche pour le développement): Horizon |
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IRD (Institute de recherche pour le développement): Horizon |
op_collection_id |
ftird |
language |
English |
topic |
Chimborazo Andean volcanism Late Pleistocene Eruptive rates Volcanic hazards Ar-40-Ar-39 geochronology |
spellingShingle |
Chimborazo Andean volcanism Late Pleistocene Eruptive rates Volcanic hazards Ar-40-Ar-39 geochronology Samaniego, Pablo Barba, D. Robin, Claude Fornari, Michel Bernard, Benjamin Eruptive history of Chimborazo volcano (Ecuador) : a large, ice-capped and hazardous compound volcano in the Northern Andes |
topic_facet |
Chimborazo Andean volcanism Late Pleistocene Eruptive rates Volcanic hazards Ar-40-Ar-39 geochronology |
description |
New fieldwork, radiometric and whole-rock chemical data permit the reconstruction of the main eruptive stages of the Chimborazo compound volcano, the highest summit of the Northern Andes. Chimborazo is composed of three successive edifices. The Basal Edifice (CH-I) was active from similar to 120 to 60 ka and resulted in a large, mostly effusive edifice which was built up during two stages of cone-building, terminating with the formation of a dome complex. This edifice was affected by a huge sector collapse around 65-60 ka which produced a major debris avalanche that spread out into the Riobamba basin, covering about 280 km(2) with an average thickness of 40 m and a total volume of similar to 10-12 km(3). After the emplacement of the Riobamba debris avalanche, eruptive activity resumed at the eastern outlet of the avalanche scar and was responsible for the construction of a less voluminous, Intermediary Edifice (CH-II), whose current remnants are the Politecnica and Martinez peaks. This edifice developed from 60 to 35 ka. Lastly, eruptive activity shifted to the west, leading to the construction of the morphologically well-preserved Young Cone (CH-Ill) which currently forms the highest summit (Whymper). The average eruptive rate of Chimborazo volcano is 0.5-0.7 km(3)/ka. However, looking at the three successive edifices individually, we estimate that there has been a progressive decrease in magma output rate from the Basal Edifice (0.7-1.0 km(3)/ka), through the Intermediary Edifice (0.4-0.7 km(3)/ka) to the Young Cone (similar to 0.1 km(3)/ka). However, during the main cone-building stages, the peak eruption rates are markedly higher, indicating significant variations in the magma output rate during the lifespan of this arc volcano. During the Holocene, the Chimborazo eruptive activity consisted of small-volume explosive events that occurred at quite regular intervals, between about 8000 and 1000 yr ago. Since the last eruption occurred between the early part of the 5th century and the end of the 7th century, and the average time interval between the events is about 1000 yr. Chimborazo must be considered as a potentially active volcano. The presence of a thick ice cap covering the summit, its steep flanks and its position above the populated lowland area of Riobamba and Ambato, are factors that result in a high potential risk.(C) 2012 Elsevier B.V. All rights reserved. |
format |
Text |
author |
Samaniego, Pablo Barba, D. Robin, Claude Fornari, Michel Bernard, Benjamin |
author_facet |
Samaniego, Pablo Barba, D. Robin, Claude Fornari, Michel Bernard, Benjamin |
author_sort |
Samaniego, Pablo |
title |
Eruptive history of Chimborazo volcano (Ecuador) : a large, ice-capped and hazardous compound volcano in the Northern Andes |
title_short |
Eruptive history of Chimborazo volcano (Ecuador) : a large, ice-capped and hazardous compound volcano in the Northern Andes |
title_full |
Eruptive history of Chimborazo volcano (Ecuador) : a large, ice-capped and hazardous compound volcano in the Northern Andes |
title_fullStr |
Eruptive history of Chimborazo volcano (Ecuador) : a large, ice-capped and hazardous compound volcano in the Northern Andes |
title_full_unstemmed |
Eruptive history of Chimborazo volcano (Ecuador) : a large, ice-capped and hazardous compound volcano in the Northern Andes |
title_sort |
eruptive history of chimborazo volcano (ecuador) : a large, ice-capped and hazardous compound volcano in the northern andes |
publishDate |
2012 |
url |
http://www.documentation.ird.fr/hor/fdi:010055831 |
genre |
Ice cap |
genre_facet |
Ice cap |
op_relation |
http://www.documentation.ird.fr/hor/fdi:010055831 oai:ird.fr:fdi:010055831 Samaniego Pablo, Barba D., Robin Claude, Fornari Michel, Bernard Benjamin. Eruptive history of Chimborazo volcano (Ecuador) : a large, ice-capped and hazardous compound volcano in the Northern Andes. Journal of Volcanology and Geothermal Research, 2012, 221, p. 33-51. |
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