Change of eruptive style during Pliocene deglaciation: from scoria cones to lava shields in southern extra-Andean Patagonia, Argentina
Slab window basalt cycles in extra-Andean Patagonia formed in a main-plateau and a post-plateau stage, during glacial and interglacial events. Here, we provide field, geochemical and geochronological data of Pliocene basalts and volcanoes from the north of Viedma lake (49° 20′–49° 30′ S). These basa...
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ftconicet:oai:ri.conicet.gov.ar:11336/142683 2023-10-09T21:47:20+02:00 Change of eruptive style during Pliocene deglaciation: from scoria cones to lava shields in southern extra-Andean Patagonia, Argentina Gonzalez Guillot, Mauricio Alberto Ponce, Juan Federico application/pdf http://hdl.handle.net/11336/142683 eng eng Springer info:eu-repo/semantics/altIdentifier/url/https://link.springer.com/10.1007/s00445-021-01466-z info:eu-repo/semantics/altIdentifier/doi/10.1007/s00445-021-01466-z http://hdl.handle.net/11336/142683 Gonzalez Guillot, Mauricio Alberto; Ponce, Juan Federico; Change of eruptive style during Pliocene deglaciation: from scoria cones to lava shields in southern extra-Andean Patagonia, Argentina; Springer; Bulletin Of Volcanology; 83; 7; 6-2021; 1-19 0258-8900 CONICET Digital CONICET info:eu-repo/semantics/restrictedAccess https://creativecommons.org/licenses/by-nc-sa/2.5/ar/ BASALT DEGLACIATION LAVA SHIELD PATAGONIA PLIOCENE SLAB WINDOW https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion ftconicet https://doi.org/10.1007/s00445-021-01466-z 2023-09-24T18:44:05Z Slab window basalt cycles in extra-Andean Patagonia formed in a main-plateau and a post-plateau stage, during glacial and interglacial events. Here, we provide field, geochemical and geochronological data of Pliocene basalts and volcanoes from the north of Viedma lake (49° 20′–49° 30′ S). These basalts share the alkaline composition and enrichment in incompatible elements of post-plateau lavas, in agreement with their radiometric ages. While most post-plateau basalts were erupted through scoria cones, we found that some effusions to the west built lava shields of scutulum type. Field evidence indicates that shields formed during or soon after deglaciation, whereas scoria cones formed before ice retreat or at interglacial stages. We obtained an Ar/Ar age of 3.59 ± 0.07 Ma for a pre-shield basalt, extruded immediately before or concomitant with till deposition. Lava shield formation occurred soon after this age. The lava shield basalts are enriched in incompatible elements. Their petrogenesis involved low degree (~ 2.5%) partial melting of a garnet lherzolite source at the waning of the post-plateau stage, followed by stagnation and high pressure fractionation. Subsequent low pressure fractionation also occurred during ascent. Pre-shield basalts evolved by slightly greater degree of partial melting (~ 3–3.5%) and lesser fractionation. We propose that during glaciation, glacial loading favoured magma ponding, probably at the base of the crust, and that during/after deglaciation lithospheric relaxation facilitated tapping of stored, more evolved magmas. Stagnation favoured outgassing, so that low ascent and eruption rates of outgassed magma triggered a change to an effusive style. Fil: Gonzalez Guillot, Mauricio Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur. Instituto de Ciencias Polares, Ambientales y Recursos Naturales; Argentina Fil: Ponce, Juan ... Article in Journal/Newspaper Antártida Tierra del Fuego CONICET Digital (Consejo Nacional de Investigaciones Científicas y Técnicas) Austral Patagonia Argentina Gonzalez ENVELOPE(-58.250,-58.250,-63.917,-63.917) Bulletin of Volcanology 83 7 |
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Open Polar |
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CONICET Digital (Consejo Nacional de Investigaciones Científicas y Técnicas) |
op_collection_id |
ftconicet |
language |
English |
topic |
BASALT DEGLACIATION LAVA SHIELD PATAGONIA PLIOCENE SLAB WINDOW https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 |
spellingShingle |
BASALT DEGLACIATION LAVA SHIELD PATAGONIA PLIOCENE SLAB WINDOW https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 Gonzalez Guillot, Mauricio Alberto Ponce, Juan Federico Change of eruptive style during Pliocene deglaciation: from scoria cones to lava shields in southern extra-Andean Patagonia, Argentina |
topic_facet |
BASALT DEGLACIATION LAVA SHIELD PATAGONIA PLIOCENE SLAB WINDOW https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 |
description |
Slab window basalt cycles in extra-Andean Patagonia formed in a main-plateau and a post-plateau stage, during glacial and interglacial events. Here, we provide field, geochemical and geochronological data of Pliocene basalts and volcanoes from the north of Viedma lake (49° 20′–49° 30′ S). These basalts share the alkaline composition and enrichment in incompatible elements of post-plateau lavas, in agreement with their radiometric ages. While most post-plateau basalts were erupted through scoria cones, we found that some effusions to the west built lava shields of scutulum type. Field evidence indicates that shields formed during or soon after deglaciation, whereas scoria cones formed before ice retreat or at interglacial stages. We obtained an Ar/Ar age of 3.59 ± 0.07 Ma for a pre-shield basalt, extruded immediately before or concomitant with till deposition. Lava shield formation occurred soon after this age. The lava shield basalts are enriched in incompatible elements. Their petrogenesis involved low degree (~ 2.5%) partial melting of a garnet lherzolite source at the waning of the post-plateau stage, followed by stagnation and high pressure fractionation. Subsequent low pressure fractionation also occurred during ascent. Pre-shield basalts evolved by slightly greater degree of partial melting (~ 3–3.5%) and lesser fractionation. We propose that during glaciation, glacial loading favoured magma ponding, probably at the base of the crust, and that during/after deglaciation lithospheric relaxation facilitated tapping of stored, more evolved magmas. Stagnation favoured outgassing, so that low ascent and eruption rates of outgassed magma triggered a change to an effusive style. Fil: Gonzalez Guillot, Mauricio Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur. Instituto de Ciencias Polares, Ambientales y Recursos Naturales; Argentina Fil: Ponce, Juan ... |
format |
Article in Journal/Newspaper |
author |
Gonzalez Guillot, Mauricio Alberto Ponce, Juan Federico |
author_facet |
Gonzalez Guillot, Mauricio Alberto Ponce, Juan Federico |
author_sort |
Gonzalez Guillot, Mauricio Alberto |
title |
Change of eruptive style during Pliocene deglaciation: from scoria cones to lava shields in southern extra-Andean Patagonia, Argentina |
title_short |
Change of eruptive style during Pliocene deglaciation: from scoria cones to lava shields in southern extra-Andean Patagonia, Argentina |
title_full |
Change of eruptive style during Pliocene deglaciation: from scoria cones to lava shields in southern extra-Andean Patagonia, Argentina |
title_fullStr |
Change of eruptive style during Pliocene deglaciation: from scoria cones to lava shields in southern extra-Andean Patagonia, Argentina |
title_full_unstemmed |
Change of eruptive style during Pliocene deglaciation: from scoria cones to lava shields in southern extra-Andean Patagonia, Argentina |
title_sort |
change of eruptive style during pliocene deglaciation: from scoria cones to lava shields in southern extra-andean patagonia, argentina |
publisher |
Springer |
url |
http://hdl.handle.net/11336/142683 |
long_lat |
ENVELOPE(-58.250,-58.250,-63.917,-63.917) |
geographic |
Austral Patagonia Argentina Gonzalez |
geographic_facet |
Austral Patagonia Argentina Gonzalez |
genre |
Antártida Tierra del Fuego |
genre_facet |
Antártida Tierra del Fuego |
op_relation |
info:eu-repo/semantics/altIdentifier/url/https://link.springer.com/10.1007/s00445-021-01466-z info:eu-repo/semantics/altIdentifier/doi/10.1007/s00445-021-01466-z http://hdl.handle.net/11336/142683 Gonzalez Guillot, Mauricio Alberto; Ponce, Juan Federico; Change of eruptive style during Pliocene deglaciation: from scoria cones to lava shields in southern extra-Andean Patagonia, Argentina; Springer; Bulletin Of Volcanology; 83; 7; 6-2021; 1-19 0258-8900 CONICET Digital CONICET |
op_rights |
info:eu-repo/semantics/restrictedAccess https://creativecommons.org/licenses/by-nc-sa/2.5/ar/ |
op_doi |
https://doi.org/10.1007/s00445-021-01466-z |
container_title |
Bulletin of Volcanology |
container_volume |
83 |
container_issue |
7 |
_version_ |
1779310419770343424 |