Evolution of Eocene to Oligocene arc-related volcanism in the North Patagonian Andes (39–41°S), prior to the break-up of the Farallon plate
Voluminous Paleogene magmatic rocks (44 to 29 Ma) are found in a retroarc position in the Northern Patagonian to Southern Central Andes (~ 39–42°S), whose origin remains controversial. Geochemical data in these Eocene to Oligocene volcanic associations are herein used to unravel their origin and und...
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2017
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00401951_v696-697_n_p70_Iannelli http://hdl.handle.net/20.500.12110/paper_00401951_v696-697_n_p70_Iannelli |
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paper:paper_00401951_v696-697_n_p70_Iannelli2023-06-08T15:04:02Z Evolution of Eocene to Oligocene arc-related volcanism in the North Patagonian Andes (39–41°S), prior to the break-up of the Farallon plate Arc volcanism Eocene-Oligocene Geochemistry Patagonian Andean margin Tectonic evolution Geochemistry Geodynamics Arc volcanism Compositional variation Geochemical data Geochemical signatures Oligocene Patagonian Andean margin Plate configuration Tectonic evolution Tectonics Eocene geochemistry magmatism Oligocene subduction zone tectonic evolution tectonic plate volcanism Andes Patagonia Voluminous Paleogene magmatic rocks (44 to 29 Ma) are found in a retroarc position in the Northern Patagonian to Southern Central Andes (~ 39–42°S), whose origin remains controversial. Geochemical data in these Eocene to Oligocene volcanic associations are herein used to unravel their origin and understand changes in subduction parameters. Geochemical signatures indicate arc-related associations and reflect changing geodynamic boundary conditions of the Andean margin through time. In particular, Eocene magmatism (~ 44 Ma; Pilcaniyeu Belt) shows an alkaline-like signature and limited slab influence. Reported contemporaneous within-plate magmatism (~ 47–43 Ma) in an easternmost position reflects a more typical enriched source. Oligocene arc-like volcanism (~ 29 Ma; El Maitén Belt), which developed in an extensional retroarc setting, shows a higher contribution from slab-derived fluids and a calc-alkaline source. A comparison with younger arc-related magmas from the region (~ 26–20 Ma), emplaced in an intra- to retroarc position (Cura Mallín and Abanico basins), indicates a progressive increase in slab-signature, associated with a tholeiitic magma source. We propose that these compositional variations could be directly related to changes in plate configuration before and after the Farallon plate break-up and the initiation of a more orthogonal convergence typical of the present Andean-type subduction zone. © 2016 Elsevier B.V. 2017 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00401951_v696-697_n_p70_Iannelli http://hdl.handle.net/20.500.12110/paper_00401951_v696-697_n_p70_Iannelli |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Arc volcanism Eocene-Oligocene Geochemistry Patagonian Andean margin Tectonic evolution Geochemistry Geodynamics Arc volcanism Compositional variation Geochemical data Geochemical signatures Oligocene Patagonian Andean margin Plate configuration Tectonic evolution Tectonics Eocene geochemistry magmatism Oligocene subduction zone tectonic evolution tectonic plate volcanism Andes Patagonia |
| spellingShingle |
Arc volcanism Eocene-Oligocene Geochemistry Patagonian Andean margin Tectonic evolution Geochemistry Geodynamics Arc volcanism Compositional variation Geochemical data Geochemical signatures Oligocene Patagonian Andean margin Plate configuration Tectonic evolution Tectonics Eocene geochemistry magmatism Oligocene subduction zone tectonic evolution tectonic plate volcanism Andes Patagonia Evolution of Eocene to Oligocene arc-related volcanism in the North Patagonian Andes (39–41°S), prior to the break-up of the Farallon plate |
| topic_facet |
Arc volcanism Eocene-Oligocene Geochemistry Patagonian Andean margin Tectonic evolution Geochemistry Geodynamics Arc volcanism Compositional variation Geochemical data Geochemical signatures Oligocene Patagonian Andean margin Plate configuration Tectonic evolution Tectonics Eocene geochemistry magmatism Oligocene subduction zone tectonic evolution tectonic plate volcanism Andes Patagonia |
| description |
Voluminous Paleogene magmatic rocks (44 to 29 Ma) are found in a retroarc position in the Northern Patagonian to Southern Central Andes (~ 39–42°S), whose origin remains controversial. Geochemical data in these Eocene to Oligocene volcanic associations are herein used to unravel their origin and understand changes in subduction parameters. Geochemical signatures indicate arc-related associations and reflect changing geodynamic boundary conditions of the Andean margin through time. In particular, Eocene magmatism (~ 44 Ma; Pilcaniyeu Belt) shows an alkaline-like signature and limited slab influence. Reported contemporaneous within-plate magmatism (~ 47–43 Ma) in an easternmost position reflects a more typical enriched source. Oligocene arc-like volcanism (~ 29 Ma; El Maitén Belt), which developed in an extensional retroarc setting, shows a higher contribution from slab-derived fluids and a calc-alkaline source. A comparison with younger arc-related magmas from the region (~ 26–20 Ma), emplaced in an intra- to retroarc position (Cura Mallín and Abanico basins), indicates a progressive increase in slab-signature, associated with a tholeiitic magma source. We propose that these compositional variations could be directly related to changes in plate configuration before and after the Farallon plate break-up and the initiation of a more orthogonal convergence typical of the present Andean-type subduction zone. © 2016 Elsevier B.V. |
| title |
Evolution of Eocene to Oligocene arc-related volcanism in the North Patagonian Andes (39–41°S), prior to the break-up of the Farallon plate |
| title_short |
Evolution of Eocene to Oligocene arc-related volcanism in the North Patagonian Andes (39–41°S), prior to the break-up of the Farallon plate |
| title_full |
Evolution of Eocene to Oligocene arc-related volcanism in the North Patagonian Andes (39–41°S), prior to the break-up of the Farallon plate |
| title_fullStr |
Evolution of Eocene to Oligocene arc-related volcanism in the North Patagonian Andes (39–41°S), prior to the break-up of the Farallon plate |
| title_full_unstemmed |
Evolution of Eocene to Oligocene arc-related volcanism in the North Patagonian Andes (39–41°S), prior to the break-up of the Farallon plate |
| title_sort |
evolution of eocene to oligocene arc-related volcanism in the north patagonian andes (39–41°s), prior to the break-up of the farallon plate |
| publishDate |
2017 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00401951_v696-697_n_p70_Iannelli http://hdl.handle.net/20.500.12110/paper_00401951_v696-697_n_p70_Iannelli |
| _version_ |
1768544631658643456 |