Early andean tectonomagmatic stages in North Patagonia: Insights from field and geochemical data
The Andes in northern Patagonia are mainly formed by Mesozoic magmatic units: the mostly Jurassic-Cretaceous North Patagonian Batholith and volcanism of the Jurassic Lago La Plata (Ibáñez) Formation as well as the mid-Cretaceous Divisadero Group. These rocks represent the development of a magmatic b...
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paper:paper_00167649_v174_n3_p405_Echaurren2023-06-08T14:38:54Z Early andean tectonomagmatic stages in North Patagonia: Insights from field and geochemical data Folguera, Andrés Geochemistry Lead Neodymium Strontium Tectonics Volcanic rocks Volcanoes Angular unconformity Crustal thickenings Fold-thrust belts Geochemical data Lower Cretaceous Northern patagonia Plate compressions Structural relationship Sedimentary rocks Andean orogeny arc-arc collision batholith compression Cretaceous crustal structure extensional tectonics isotopic ratio magmatism tectonic evolution tectonic setting volcanism Andes Patagonia The Andes in northern Patagonia are mainly formed by Mesozoic magmatic units: the mostly Jurassic-Cretaceous North Patagonian Batholith and volcanism of the Jurassic Lago La Plata (Ibáñez) Formation as well as the mid-Cretaceous Divisadero Group. These rocks represent the development of a magmatic belt through Jurassic-mid-Cretaceous time, during a switch of the tectonic regime from extension to compression. To study arc evolution during this transition, we carried out fieldwork and geochemical sampling at c. 43°S, clarifying structural relationships and characterizing the magmatic sources. Multi-element diagrams for both volcanic units suggest a slab-derived signature, whereas isotopic ratios (Sr-Nd-Pb) indicate parental melts sourced from the subduction-modified asthenospheric mantle interacting with crustal sources during their emplacement. An angular unconformity is identified between the synextensional Jurassic volcanic rocks and Lower Cretaceous sedimentary rocks beneath the mid-Cretaceous sequences. Although this deformational event was simultaneous with generalized overriding plate compression, geochemical ratios indicate an immature Aptian-Albian arc with no associated crustal thickening. Late Jurassic to mid-Cretaceous arc settlement after a trenchward retraction of magmatism from the foreland between c. 41 and 45°S, with an associated increase in slab dip angle, may have provoked crustal softening facilitating the subsequent initial fold-thrust belt growth. © 2017 The Author(s). Published by The Geological Society of London. All rights reserved. Fil:Folguera, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2017 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00167649_v174_n3_p405_Echaurren http://hdl.handle.net/20.500.12110/paper_00167649_v174_n3_p405_Echaurren |
| 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 Lead Neodymium Strontium Tectonics Volcanic rocks Volcanoes Angular unconformity Crustal thickenings Fold-thrust belts Geochemical data Lower Cretaceous Northern patagonia Plate compressions Structural relationship Sedimentary rocks Andean orogeny arc-arc collision batholith compression Cretaceous crustal structure extensional tectonics isotopic ratio magmatism tectonic evolution tectonic setting volcanism Andes Patagonia |
| spellingShingle |
Geochemistry Lead Neodymium Strontium Tectonics Volcanic rocks Volcanoes Angular unconformity Crustal thickenings Fold-thrust belts Geochemical data Lower Cretaceous Northern patagonia Plate compressions Structural relationship Sedimentary rocks Andean orogeny arc-arc collision batholith compression Cretaceous crustal structure extensional tectonics isotopic ratio magmatism tectonic evolution tectonic setting volcanism Andes Patagonia Folguera, Andrés Early andean tectonomagmatic stages in North Patagonia: Insights from field and geochemical data |
| topic_facet |
Geochemistry Lead Neodymium Strontium Tectonics Volcanic rocks Volcanoes Angular unconformity Crustal thickenings Fold-thrust belts Geochemical data Lower Cretaceous Northern patagonia Plate compressions Structural relationship Sedimentary rocks Andean orogeny arc-arc collision batholith compression Cretaceous crustal structure extensional tectonics isotopic ratio magmatism tectonic evolution tectonic setting volcanism Andes Patagonia |
| description |
The Andes in northern Patagonia are mainly formed by Mesozoic magmatic units: the mostly Jurassic-Cretaceous North Patagonian Batholith and volcanism of the Jurassic Lago La Plata (Ibáñez) Formation as well as the mid-Cretaceous Divisadero Group. These rocks represent the development of a magmatic belt through Jurassic-mid-Cretaceous time, during a switch of the tectonic regime from extension to compression. To study arc evolution during this transition, we carried out fieldwork and geochemical sampling at c. 43°S, clarifying structural relationships and characterizing the magmatic sources. Multi-element diagrams for both volcanic units suggest a slab-derived signature, whereas isotopic ratios (Sr-Nd-Pb) indicate parental melts sourced from the subduction-modified asthenospheric mantle interacting with crustal sources during their emplacement. An angular unconformity is identified between the synextensional Jurassic volcanic rocks and Lower Cretaceous sedimentary rocks beneath the mid-Cretaceous sequences. Although this deformational event was simultaneous with generalized overriding plate compression, geochemical ratios indicate an immature Aptian-Albian arc with no associated crustal thickening. Late Jurassic to mid-Cretaceous arc settlement after a trenchward retraction of magmatism from the foreland between c. 41 and 45°S, with an associated increase in slab dip angle, may have provoked crustal softening facilitating the subsequent initial fold-thrust belt growth. © 2017 The Author(s). Published by The Geological Society of London. All rights reserved. |
| author |
Folguera, Andrés |
| author_facet |
Folguera, Andrés |
| author_sort |
Folguera, Andrés |
| title |
Early andean tectonomagmatic stages in North Patagonia: Insights from field and geochemical data |
| title_short |
Early andean tectonomagmatic stages in North Patagonia: Insights from field and geochemical data |
| title_full |
Early andean tectonomagmatic stages in North Patagonia: Insights from field and geochemical data |
| title_fullStr |
Early andean tectonomagmatic stages in North Patagonia: Insights from field and geochemical data |
| title_full_unstemmed |
Early andean tectonomagmatic stages in North Patagonia: Insights from field and geochemical data |
| title_sort |
early andean tectonomagmatic stages in north patagonia: insights from field and geochemical data |
| publishDate |
2017 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00167649_v174_n3_p405_Echaurren http://hdl.handle.net/20.500.12110/paper_00167649_v174_n3_p405_Echaurren |
| work_keys_str_mv |
AT folgueraandres earlyandeantectonomagmaticstagesinnorthpatagoniainsightsfromfieldandgeochemicaldata |
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1768541547423334400 |