Paleogene and Neogene magmatism in the Valle del Cura region: New perspective on the evolution of the Pampean flat slab, San Juan province, Argentina
The Valle del Cura region is characterized by a thick volcanic and volcaniclastic sequence that records the Tertiary arc and backarc magmatic evolution of the Argentine Main Cordillera over the modern Pampean flatslab at 29.5-30°S. During the Eocene, a retroarc basin developed, represented by the Va...
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2007
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v24_n2-4_p117_Litvak http://hdl.handle.net/20.500.12110/paper_08959811_v24_n2-4_p117_Litvak |
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paper:paper_08959811_v24_n2-4_p117_Litvak2023-06-08T15:48:20Z Paleogene and Neogene magmatism in the Valle del Cura region: New perspective on the evolution of the Pampean flat slab, San Juan province, Argentina Litvak, Vanesa Dafne Poma, Stella Maris Geochemistry Geoquímica Neogene Neogeno Paleogene Paleogeno Valle del Cura Volcanism Volcanismo basin evolution chemical property igneous geochemistry magma magmatism Neogene Paleogene subduction zone volcanic rock volcanism Argentina San Juan [Argentina] Sierras Pampeanas South America Valle del Cura Cura The Valle del Cura region is characterized by a thick volcanic and volcaniclastic sequence that records the Tertiary arc and backarc magmatic evolution of the Argentine Main Cordillera over the modern Pampean flatslab at 29.5-30°S. During the Eocene, a retroarc basin developed, represented by the Valle del Cura Formation synorogenic volcanosedimentary sequence, which includes rhyolites and dacitic tuffs. These silicic volcanic rocks have weak arc chemical signatures and high lithophile element concentrations and are isotopically enriched relative to the late Oligocene-early Miocene volcanic rocks that followed them. Their chemical characteristics fit with eruption through a thin crust. The Valle de Cura Formation was followed by the Oligocene-early Miocene Doña Ana Group volcanic sequence, which erupted at and near the arc front west of the border with Chile. The Doña Ana Group volcanic rocks have calc-alkaline chemical characteristics consistent with parental magmas forming in a mantle wedge and erupting through a normal thickness crust (35 km). Subsequent shallowing of the downgoing Nazca plate caused the volcanic front to migrate eastward. The volcanic sequences of the middle Miocene Cerro de las Tórtolas Formation erupted at this new arc front, essentially at the Argentine border. Two stages are recognized: an older one (16-14 Ma) in which magmas appear to have erupted through a normal thickness crust (30-35 km) and a younger one (13-10 Ma) in which the steeper REE pattern suggests the magmas last equilibrated with higher pressure residual mineral assemblages in a thicker crust. Isotopic ratios in the younger group are consistent with an increase in original crustal components and crust introduced into the mantle source by forearc subduction erosion. A peak in forearc subduction erosion near 12-10 Ma is consistent with when the main part of the Juan Fernandez Ridge began to subduct beneath the region. In addition to late Miocene Tambo Formation dacitic ignimbrites, the younger Cerro de las Tórtolas Formation volcanic rocks erupted at the height of contractional deformation in the Valle del Cura and to the east. The last important volcanic sequence to erupt in the Valle del Cura is the late Miocene Vacas Heladas Ignimbrite, the most isotopically enriched Tertiary magmas in the Valle del Cura that contain the highest proportion of crustal components. Subsequently volcanism ceased in the region in response to shallowing of the subduction zone. © 2007 Elsevier Ltd. All rights reserved. Fil:Litvak, V.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Poma, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2007 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v24_n2-4_p117_Litvak http://hdl.handle.net/20.500.12110/paper_08959811_v24_n2-4_p117_Litvak |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Geochemistry Geoquímica Neogene Neogeno Paleogene Paleogeno Valle del Cura Volcanism Volcanismo basin evolution chemical property igneous geochemistry magma magmatism Neogene Paleogene subduction zone volcanic rock volcanism Argentina San Juan [Argentina] Sierras Pampeanas South America Valle del Cura Cura |
| spellingShingle |
Geochemistry Geoquímica Neogene Neogeno Paleogene Paleogeno Valle del Cura Volcanism Volcanismo basin evolution chemical property igneous geochemistry magma magmatism Neogene Paleogene subduction zone volcanic rock volcanism Argentina San Juan [Argentina] Sierras Pampeanas South America Valle del Cura Cura Litvak, Vanesa Dafne Poma, Stella Maris Paleogene and Neogene magmatism in the Valle del Cura region: New perspective on the evolution of the Pampean flat slab, San Juan province, Argentina |
| topic_facet |
Geochemistry Geoquímica Neogene Neogeno Paleogene Paleogeno Valle del Cura Volcanism Volcanismo basin evolution chemical property igneous geochemistry magma magmatism Neogene Paleogene subduction zone volcanic rock volcanism Argentina San Juan [Argentina] Sierras Pampeanas South America Valle del Cura Cura |
| description |
The Valle del Cura region is characterized by a thick volcanic and volcaniclastic sequence that records the Tertiary arc and backarc magmatic evolution of the Argentine Main Cordillera over the modern Pampean flatslab at 29.5-30°S. During the Eocene, a retroarc basin developed, represented by the Valle del Cura Formation synorogenic volcanosedimentary sequence, which includes rhyolites and dacitic tuffs. These silicic volcanic rocks have weak arc chemical signatures and high lithophile element concentrations and are isotopically enriched relative to the late Oligocene-early Miocene volcanic rocks that followed them. Their chemical characteristics fit with eruption through a thin crust. The Valle de Cura Formation was followed by the Oligocene-early Miocene Doña Ana Group volcanic sequence, which erupted at and near the arc front west of the border with Chile. The Doña Ana Group volcanic rocks have calc-alkaline chemical characteristics consistent with parental magmas forming in a mantle wedge and erupting through a normal thickness crust (35 km). Subsequent shallowing of the downgoing Nazca plate caused the volcanic front to migrate eastward. The volcanic sequences of the middle Miocene Cerro de las Tórtolas Formation erupted at this new arc front, essentially at the Argentine border. Two stages are recognized: an older one (16-14 Ma) in which magmas appear to have erupted through a normal thickness crust (30-35 km) and a younger one (13-10 Ma) in which the steeper REE pattern suggests the magmas last equilibrated with higher pressure residual mineral assemblages in a thicker crust. Isotopic ratios in the younger group are consistent with an increase in original crustal components and crust introduced into the mantle source by forearc subduction erosion. A peak in forearc subduction erosion near 12-10 Ma is consistent with when the main part of the Juan Fernandez Ridge began to subduct beneath the region. In addition to late Miocene Tambo Formation dacitic ignimbrites, the younger Cerro de las Tórtolas Formation volcanic rocks erupted at the height of contractional deformation in the Valle del Cura and to the east. The last important volcanic sequence to erupt in the Valle del Cura is the late Miocene Vacas Heladas Ignimbrite, the most isotopically enriched Tertiary magmas in the Valle del Cura that contain the highest proportion of crustal components. Subsequently volcanism ceased in the region in response to shallowing of the subduction zone. © 2007 Elsevier Ltd. All rights reserved. |
| author |
Litvak, Vanesa Dafne Poma, Stella Maris |
| author_facet |
Litvak, Vanesa Dafne Poma, Stella Maris |
| author_sort |
Litvak, Vanesa Dafne |
| title |
Paleogene and Neogene magmatism in the Valle del Cura region: New perspective on the evolution of the Pampean flat slab, San Juan province, Argentina |
| title_short |
Paleogene and Neogene magmatism in the Valle del Cura region: New perspective on the evolution of the Pampean flat slab, San Juan province, Argentina |
| title_full |
Paleogene and Neogene magmatism in the Valle del Cura region: New perspective on the evolution of the Pampean flat slab, San Juan province, Argentina |
| title_fullStr |
Paleogene and Neogene magmatism in the Valle del Cura region: New perspective on the evolution of the Pampean flat slab, San Juan province, Argentina |
| title_full_unstemmed |
Paleogene and Neogene magmatism in the Valle del Cura region: New perspective on the evolution of the Pampean flat slab, San Juan province, Argentina |
| title_sort |
paleogene and neogene magmatism in the valle del cura region: new perspective on the evolution of the pampean flat slab, san juan province, argentina |
| publishDate |
2007 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v24_n2-4_p117_Litvak http://hdl.handle.net/20.500.12110/paper_08959811_v24_n2-4_p117_Litvak |
| work_keys_str_mv |
AT litvakvanesadafne paleogeneandneogenemagmatisminthevalledelcuraregionnewperspectiveontheevolutionofthepampeanflatslabsanjuanprovinceargentina AT pomastellamaris paleogeneandneogenemagmatisminthevalledelcuraregionnewperspectiveontheevolutionofthepampeanflatslabsanjuanprovinceargentina |
| _version_ |
1768545098920886272 |