Picos Volcanic Fissural System: Difference between revisions
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{{Geobox|Range |
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{{Orphan|date=April 2012}} |
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<!-- *** Heading *** --> |
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| name = Picos Volcanic Fissural System |
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{{Infobox mountain |
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| native_name = Sistema Vulcânico Fissural dos Picos |
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| name = Picos Volcanic System |
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| other_name = |
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| photo = |
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| category = [[Fissure vent]] |
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| photo_size = |
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| native_category = Eurpção fissural |
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| photo_caption = |
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<!-- *** Names **** --> |
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| elevation_m = 350 |
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| etymology = ''picos'', [[Portuguese language|Portuguese]] for ''peaks'' |
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| elevation_ref = |
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| official_name = Sistema Vulcânico Fissural dos Picos |
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| location = {{flagicon|Azores}} [[Azores]], [[São Miguel Island]]. {{flagicon|Portugal}} [[Portugal]] |
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| nickname = |
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| type = [[Pyroclastic cones]] |
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<!-- *** Image *** --> |
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| last_eruption = October 1652 |
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| image = |
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| image_caption = |
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| image_size = 235 |
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<!-- *** Country *** --> |
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| country = {{flag|Portugal}} |
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| state_type = Autonomous Region |
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| state = {{flag|Azores|name=Azores}} |
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| region_type = Islands |
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| region = Eastern Group |
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<!-- *** Family *** --> |
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| parent_type = Location |
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| parent = Azores Platform |
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| parent1_type = Location |
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| parent1 = Mid-Atlantic Ridge |
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| parent2_type = Location |
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| parent2 = Atlantic Ocean |
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| range = Azores |
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| range_type = Archipelago |
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| border = |
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| part_type = Municipalities |
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| part = Lagoa |
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| part1 = Ponta Delgada |
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| part2 = Ribeira Grande |
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| landmark = |
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| river = |
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<!-- *** Locations *** --> |
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| highest = Pico das Éguas |
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| highest_location = Serra Gorda |
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| highest_region = [[Ponta Delgada]] |
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| highest_country = [[São Miguel Island|São Miguel]] |
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| highest_elevation = 874 |
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| highest_lat_d = 37 |
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| highest_lat_m = 47 |
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| highest_lat_s = 11 |
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| highest_lat_NS = N |
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| highest_long_d = 25 |
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| highest_long_m = 28 |
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| highest_long_s = 23 |
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| highest_long_EW = W |
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| lowest = Sea level |
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| lowest_location = Atlantic Ocean |
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| lowest_region = |
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| lowest_country = |
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| lowest_elevation = 0 |
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| lowest_lat_d = |
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| lowest_lat_m = |
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| lowest_lat_s = |
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| lowest_lat_NS = |
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| lowest_long_d = |
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| lowest_long_m = |
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| lowest_long_s = |
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| lowest_long_EW = |
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<!-- *** Dimensions *** --> |
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| length = |
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| length_orientation = West-East |
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| width = |
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| width_orientation = North-South |
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| area = 200 |
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<!-- *** Features *** --> |
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| geology = Alkali basalt |
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| geology1 = Tephra |
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| geology2 = Trachyte |
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| geology3 = Trachybasalt |
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| orogeny = Volcanism |
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| period = Pleistocene |
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| biome = Temperate |
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| biome1 = [[Mediterranean climate|Mediterranean]] |
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| plant = |
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| animal = |
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<!-- *** Free fields *** --> |
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| free_type = |
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| free = |
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<!-- *** Maps *** --> |
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| map = |
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| map_size = 235 |
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| map_caption = Location of the Picos Fissural Zone on the island of São Miguel |
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| map_background = |
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| map_location = |
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| map_locator = |
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<!-- *** Website *** --> |
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| commons = |
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| website = |
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<!-- *** Footnotes *** --> |
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| footnotes = |
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}} |
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The '''Picos Volcanic System''' is a system of scoria |
The '''Picos Volcanic Fissural System''' ({{lang-pt|Sistema Vulcânico Fissural dos Picos}}) is a system of [[scoria cone]]s that build up the central region of the island of [[Sao Miguel Island|São Miguel]] (between Sete Cidades and Água de Pau volcanoes). This volcano is very young with most of it only 5000 years old. The only recorded eruption was in 1652, but seven other eruptions have taken place in the cinder cone group in the last 10,000 years. |
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__NOTOC__ |
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== |
==History== |
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This volcanic system is the most recently formed on the island of São Miguel, with its eruptive history dominated by [[Hawaiian eruption|Hawaiian]], basaltic and [[Strombolian eruption|Stromboli]] phases.<ref name="CVARG">{{cite web |url=http://www.cvarg.azores.gov.pt/vulcoes-activos/Paginas/svfpicos.aspx |title= Sistema Vulcânico Fissural dos Picos |language=Portuguese |publisher=entro de Vulcanologia e Avaliação de Riscos Geológicos da Universidade dos Açores/Centro de Informação e Vigilância Sismovulcânica dos Açores |language=Portuguese |location=Ponta Delgada (Azores), Portugal}}</ref> |
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The group is Monogenetic, and is aligned on fissures. The field contains around 200 cones. The group is Tephrite Basanite-Trachyte in composition, although more recent eruptions have been mainly basaltic. |
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In the last 5000 years, there have been approximately 30 eruptions, with the most recent events occurring with recorded human history.<ref name=CVARG/> |
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The first, in 1563, succeeded a [[Phreatic eruption|Phreato]][[Plinian eruption|plinian eruption]] centring on the volcano of Água de Pau.<ref name=CVARG/> During this 1563 eruption, known as the Pico do Sapateiro or Queimado, basalt lava flows reached as far as Ribeira Seca, in the north coast. The second eruption, which started on 19 October 1652, resulted in the formation of three Trachyte domes and involved explosive phases of [[Vulcanian eruption]]s, by the time the eruptions end on 26 October 1652.<ref name=CVARG/> This, more recent eruption, was a markedly eruptive/explosive event, composed of evolved magma that generally does not characterize the Picos region. |
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==Geography== |
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The Picos fissural system is located in the central-western part of the island of São Miguel, delimited in the south-east by the caldera/massif of Sete Cidades and on the east by the Água de Pau massif, running approximately {{convert|23|km|mi}} and extending to north and southern coasts.<ref name=CVARG/> The landscape is dominated by the presence of approximately 300 monogenic cones, composed of scoria and lava flows.<ref name=CVARG/> Similarly, the area is punctuated by [[maar]]s, [[pumice]] cones and [[lava dome]]s, in particular in the transitional zones between the adjacent central volcanoes.<ref name=CVARG/> |
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The volcanostratigraphy of magmas/lava flows of the region include deposits between 2200 and 2800 years B.C., while radiometric deposits from the principal areas of population (Ponta Delgada) are from 12300 B.C.<ref name=CVARG/> |
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==Eruptions== |
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===1652 Eruption=== |
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An eruption took place on the 19 October 1652, in the eastern part of the group, southwest of the Fogo 1 cone. The eruption was an VEI 2 explosive eruption that produced lava flows, the eruption ended on the 26 October 1652. |
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==References== |
==References== |
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;Notes |
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* Global Volcanism Program |
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{{Reflist|30em}} |
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* Volcanoes of The World 3rd ed. |
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;Sources |
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* {{citation |last=Booth |first=B. |first2=R. |last2=Croasdale |first3=G. |last3=Walkert |year=1978 |title=A quantitative study of five thousand years of volcanism on S. Miguel, Azores. |publisher= Royal Society of London |issue=228 |pages=271-319}} |
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* {{citation |last=Moore |first=R |last2=Rubin |first2=M |year=1991 |contribution=Radiocarbon dates for lava flows and piroclastic deposits on São Miguel, Azores |title=Radiocarbon |issue=33:1 |pages=151-164}} |
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* {{citation |last=Ferreira |first=Teresa |year=2000 |title=Caracterização da actividade vulcânica da ilha de S. Miguel (Açores): vulcanismo basáltico recente e zonas de desgaseificação. Avaliação de riscos. Tese de Doutoramento no ramo de Geologia, especialidade de Vulcanologia |publisher=University of the Azores/Departamento de Geociências |pages=248 |language=Portuguese}} |
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[[Category:Geology of the Azores]] |
[[Category:Geology of the Azores]] |
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Revision as of 16:20, 25 December 2014
Template:Geobox The Picos Volcanic Fissural System (Template:Lang-pt) is a system of scoria cones that build up the central region of the island of São Miguel (between Sete Cidades and Água de Pau volcanoes). This volcano is very young with most of it only 5000 years old. The only recorded eruption was in 1652, but seven other eruptions have taken place in the cinder cone group in the last 10,000 years.
History
This volcanic system is the most recently formed on the island of São Miguel, with its eruptive history dominated by Hawaiian, basaltic and Stromboli phases.[1]
In the last 5000 years, there have been approximately 30 eruptions, with the most recent events occurring with recorded human history.[1]
The first, in 1563, succeeded a Phreatoplinian eruption centring on the volcano of Água de Pau.[1] During this 1563 eruption, known as the Pico do Sapateiro or Queimado, basalt lava flows reached as far as Ribeira Seca, in the north coast. The second eruption, which started on 19 October 1652, resulted in the formation of three Trachyte domes and involved explosive phases of Vulcanian eruptions, by the time the eruptions end on 26 October 1652.[1] This, more recent eruption, was a markedly eruptive/explosive event, composed of evolved magma that generally does not characterize the Picos region.
Geography
The Picos fissural system is located in the central-western part of the island of São Miguel, delimited in the south-east by the caldera/massif of Sete Cidades and on the east by the Água de Pau massif, running approximately 23 kilometres (14 mi) and extending to north and southern coasts.[1] The landscape is dominated by the presence of approximately 300 monogenic cones, composed of scoria and lava flows.[1] Similarly, the area is punctuated by maars, pumice cones and lava domes, in particular in the transitional zones between the adjacent central volcanoes.[1]
The volcanostratigraphy of magmas/lava flows of the region include deposits between 2200 and 2800 years B.C., while radiometric deposits from the principal areas of population (Ponta Delgada) are from 12300 B.C.[1]
References
- Notes
- Sources
- Booth, B.; Croasdale, R.; Walkert, G. (1978), A quantitative study of five thousand years of volcanism on S. Miguel, Azores., Royal Society of London, pp. 271–319
- Moore, R; Rubin, M (1991), "Radiocarbon dates for lava flows and piroclastic deposits on São Miguel, Azores", Radiocarbon, pp. 151–164
- Ferreira, Teresa (2000), Caracterização da actividade vulcânica da ilha de S. Miguel (Açores): vulcanismo basáltico recente e zonas de desgaseificação. Avaliação de riscos. Tese de Doutoramento no ramo de Geologia, especialidade de Vulcanologia (in Portuguese), University of the Azores/Departamento de Geociências, p. 248