Mantle derived crystal-poor rhyolitic ignimbrites: Eruptive mechanism from geochemical and geochronological data of the Piedra Parada caldera, Southern Argentina
Trace elements, isotopic modeling and U-Th-Pb SHRIMP zircon age constraints are used to reconstruct the eruption history and magmatic processes of the Piedra Parada Caldera. In the early Eocene, the crystal-poor Barda Colorada ignimbrite (BCI), having >>15% micro-porphyritic crystals with resp...
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| Format: | Article |
| Language: | English |
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Elsevier
2018-09-01
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| Series: | Geoscience Frontiers |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674987117301603 |
| _version_ | 1797707213038419968 |
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| author | Eugenio Aragon Antonio Castro Juan Diaz-Alvarado Lucio Pinotti Fernando D′eramo Manuel Demartis Jorge Coniglio Irene Hernando Carmen Rodriguez |
| author_facet | Eugenio Aragon Antonio Castro Juan Diaz-Alvarado Lucio Pinotti Fernando D′eramo Manuel Demartis Jorge Coniglio Irene Hernando Carmen Rodriguez |
| author_sort | Eugenio Aragon |
| collection | DOAJ |
| description | Trace elements, isotopic modeling and U-Th-Pb SHRIMP zircon age constraints are used to reconstruct the eruption history and magmatic processes of the Piedra Parada Caldera. In the early Eocene, the crystal-poor Barda Colorada ignimbrite (BCI), having >>15% micro-porphyritic crystals with respect to magmatic components, erupted a volume estimated in more than 300 km3. The Piedra Parada caldera is located in the Patagonian Andes foreland, at the southern end of the calderas field of the Pilcaniyeu Volcanic Belt (PVB). This belt is related to an extensional tectonic setting as a result of the collision of the Farallon-Aluk ridge with South America, which enabled the development of a transform ocean/continental plate margin followed by the detachment of the Aluk plate and the opening of a slab window. The BCI extra-caldera Plateau is a >100 m thick deposit, having a lower unit with high silica (SiO2 > 76 wt.%), potassium poor rhyolitic composition (trondhjemitic like magma), and an upper unit with normal to high potassium rhyolitic composition (granitic like magma). A trace elements modeling of the BCI units shows that the BCI lower and upper units did not evolve from fractionation or immiscibility in the shallow magma reservoir. The BCI also have a primitive isotopic signature (initial 87Sr/86Sr = 0.7031–0.7049 and εNd = +3.4 to +3.65). Thus, tectonic, compositional and isotopic constraints suggest the fast ascent of high silica magmas to a shallow reservoir, and point to an upper mantle origin for these rhyolitic magmas in a transitional (Orogenic-Anorogenic) tectono-magmatic setting. U-Th-Pb SHRIMP zircon crystallization ages of the Syn-caldera stage BCI units (56–51.5 Ma) show a protracted life of 5 Ma for this caldera reservoir. The age of 52.9 ± 0.3 Ma is considered the best fit for the possible maximum age for the caldera collapse. The Late-caldera magmatism has trachyandesitic and rhyolitic compositions. The trace element modeling suggests that these rhyolites evolve from the trachyandesites and do not evolve from the BCI residual magma. The trachyandesites have U-Th-Pb SHRIMP zircon crystallization ages of 52 ± 1 Ma, suggesting that the caldera eruption was triggered by the arrival of the trachyandesitic magma. Keywords: Mantle derived rhyolite, Crystal-poor ignimbrite, Bimodal volcanism, Slab window volcanism, K poor-rhyolite |
| first_indexed | 2024-03-12T06:04:01Z |
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| issn | 1674-9871 |
| language | English |
| last_indexed | 2024-03-12T06:04:01Z |
| publishDate | 2018-09-01 |
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| spelling | doaj.art-aa7e46bd970e485db4f46e3a954e11422023-09-03T03:53:19ZengElsevierGeoscience Frontiers1674-98712018-09-019515291553Mantle derived crystal-poor rhyolitic ignimbrites: Eruptive mechanism from geochemical and geochronological data of the Piedra Parada caldera, Southern ArgentinaEugenio Aragon0Antonio Castro1Juan Diaz-Alvarado2Lucio Pinotti3Fernando D′eramo4Manuel Demartis5Jorge Coniglio6Irene Hernando7Carmen Rodriguez8Centro de Investigaciones Geológicas (UNLP-CONICET), 1 No 644, (1900) La Plata, Buenos Aires, Argentina; Corresponding author.Departamento de Geología, Universidad de Huelva, 21071 Huelva, SpainDepartamento de Geología, Universidad de Atacama, Copayapu 485, Copiapó, ChileDepartamento de Geología, Universidad Nacional de Río Cuarto, (UNRC-CONICET), Ruta 36 km 601, Río Cuarto, Córdoba, ArgentinaDepartamento de Geología, Universidad Nacional de Río Cuarto, (UNRC-CONICET), Ruta 36 km 601, Río Cuarto, Córdoba, ArgentinaDepartamento de Geología, Universidad Nacional de Río Cuarto, (UNRC-CONICET), Ruta 36 km 601, Río Cuarto, Córdoba, ArgentinaDepartamento de Geología, Universidad Nacional de Río Cuarto, (UNRC-CONICET), Ruta 36 km 601, Río Cuarto, Córdoba, ArgentinaCentro de Investigaciones Geológicas (UNLP-CONICET), 1 No 644, (1900) La Plata, Buenos Aires, ArgentinaDepartamento de Geología, Universidad de Huelva, 21071 Huelva, SpainTrace elements, isotopic modeling and U-Th-Pb SHRIMP zircon age constraints are used to reconstruct the eruption history and magmatic processes of the Piedra Parada Caldera. In the early Eocene, the crystal-poor Barda Colorada ignimbrite (BCI), having >>15% micro-porphyritic crystals with respect to magmatic components, erupted a volume estimated in more than 300 km3. The Piedra Parada caldera is located in the Patagonian Andes foreland, at the southern end of the calderas field of the Pilcaniyeu Volcanic Belt (PVB). This belt is related to an extensional tectonic setting as a result of the collision of the Farallon-Aluk ridge with South America, which enabled the development of a transform ocean/continental plate margin followed by the detachment of the Aluk plate and the opening of a slab window. The BCI extra-caldera Plateau is a >100 m thick deposit, having a lower unit with high silica (SiO2 > 76 wt.%), potassium poor rhyolitic composition (trondhjemitic like magma), and an upper unit with normal to high potassium rhyolitic composition (granitic like magma). A trace elements modeling of the BCI units shows that the BCI lower and upper units did not evolve from fractionation or immiscibility in the shallow magma reservoir. The BCI also have a primitive isotopic signature (initial 87Sr/86Sr = 0.7031–0.7049 and εNd = +3.4 to +3.65). Thus, tectonic, compositional and isotopic constraints suggest the fast ascent of high silica magmas to a shallow reservoir, and point to an upper mantle origin for these rhyolitic magmas in a transitional (Orogenic-Anorogenic) tectono-magmatic setting. U-Th-Pb SHRIMP zircon crystallization ages of the Syn-caldera stage BCI units (56–51.5 Ma) show a protracted life of 5 Ma for this caldera reservoir. The age of 52.9 ± 0.3 Ma is considered the best fit for the possible maximum age for the caldera collapse. The Late-caldera magmatism has trachyandesitic and rhyolitic compositions. The trace element modeling suggests that these rhyolites evolve from the trachyandesites and do not evolve from the BCI residual magma. The trachyandesites have U-Th-Pb SHRIMP zircon crystallization ages of 52 ± 1 Ma, suggesting that the caldera eruption was triggered by the arrival of the trachyandesitic magma. Keywords: Mantle derived rhyolite, Crystal-poor ignimbrite, Bimodal volcanism, Slab window volcanism, K poor-rhyolitehttp://www.sciencedirect.com/science/article/pii/S1674987117301603 |
| spellingShingle | Eugenio Aragon Antonio Castro Juan Diaz-Alvarado Lucio Pinotti Fernando D′eramo Manuel Demartis Jorge Coniglio Irene Hernando Carmen Rodriguez Mantle derived crystal-poor rhyolitic ignimbrites: Eruptive mechanism from geochemical and geochronological data of the Piedra Parada caldera, Southern Argentina Geoscience Frontiers |
| title | Mantle derived crystal-poor rhyolitic ignimbrites: Eruptive mechanism from geochemical and geochronological data of the Piedra Parada caldera, Southern Argentina |
| title_full | Mantle derived crystal-poor rhyolitic ignimbrites: Eruptive mechanism from geochemical and geochronological data of the Piedra Parada caldera, Southern Argentina |
| title_fullStr | Mantle derived crystal-poor rhyolitic ignimbrites: Eruptive mechanism from geochemical and geochronological data of the Piedra Parada caldera, Southern Argentina |
| title_full_unstemmed | Mantle derived crystal-poor rhyolitic ignimbrites: Eruptive mechanism from geochemical and geochronological data of the Piedra Parada caldera, Southern Argentina |
| title_short | Mantle derived crystal-poor rhyolitic ignimbrites: Eruptive mechanism from geochemical and geochronological data of the Piedra Parada caldera, Southern Argentina |
| title_sort | mantle derived crystal poor rhyolitic ignimbrites eruptive mechanism from geochemical and geochronological data of the piedra parada caldera southern argentina |
| url | http://www.sciencedirect.com/science/article/pii/S1674987117301603 |
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