Repeated eastward shifts of arc magmatism in the Southern Andes: A revision to the long-term pattern of Andean uplift and magmatism
The Southern Andes have been built through the stacking of crustal sheets in discrete periods during the last 100 My. The first important shortening took place in Late Cretaceous at the time of eastward arc expansions potentially linked to two areas of subducted slab shallowings of 200 and 800 km wi...
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2011
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v32_n4_p531_Folguera http://hdl.handle.net/20.500.12110/paper_08959811_v32_n4_p531_Folguera |
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paper:paper_08959811_v32_n4_p531_Folguera2023-06-08T15:48:36Z Repeated eastward shifts of arc magmatism in the Southern Andes: A revision to the long-term pattern of Andean uplift and magmatism Arc magmatism Mountain uplift Slab shallowing Synorogenic sequences asthenosphere Cretaceous crustal shortening crustal structure emplacement Eocene foreland basin magmatism mountain region oceanic lithosphere stacking subduction zone uplift Andes Argentina Chubut The Southern Andes have been built through the stacking of crustal sheets in discrete periods during the last 100 My. The first important shortening took place in Late Cretaceous at the time of eastward arc expansions potentially linked to two areas of subducted slab shallowings of 200 and 800 km wide respectively. These shallowings have progressed to two smaller flat slabs in Eocene times, where rather anhydrous subducted slabs generated a discontinuous arc emplaced in the foreland area at the time of mountain building. Discrete segments of the former Late Cretaceous slab shallowings would have fallen down at this time producing early slab steepening settings where within-plate products and extensional basins developed such as in the southern Chubut Province. Then Late Oligocene times coincide with the final steepening of the broad Late Cretaceous to Eocene shallow subduction zone with the emplacement of voluminous volcanic plateaux in central Patagonia and extensional basins in the hinterland zone. Lately a long quiescence period was interrupted by the development of three Miocene shallow subduction settings more than 400 km long each, evidenced by arc expansions and associated with Andean construction. Most of these areas were extensionally reactivated in the last 5 My at the time of retraction and steepening of formerly shallow subduction zones, being associated with voluminous mantle derived materials and shallow asthenospheric injection. While some of these shallow subduction configurations could be explained by subduction of highly buoyant oceanic lithosphere related to seismic ridges, in particular those of the Aluk/Farallones and Chilean ridges, other mechanisms remain more speculative. The alternation of shallow subduction zones and their steepening in the last 100 My in the Southern Andes explain location and timing of main magmatic fluxes in the arc and retroarc areas, as well as the presence of coeval foreland mountain systems east of the Main Andes. © 2011 Elsevier Ltd. 2011 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v32_n4_p531_Folguera http://hdl.handle.net/20.500.12110/paper_08959811_v32_n4_p531_Folguera |
| 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 magmatism Mountain uplift Slab shallowing Synorogenic sequences asthenosphere Cretaceous crustal shortening crustal structure emplacement Eocene foreland basin magmatism mountain region oceanic lithosphere stacking subduction zone uplift Andes Argentina Chubut |
| spellingShingle |
Arc magmatism Mountain uplift Slab shallowing Synorogenic sequences asthenosphere Cretaceous crustal shortening crustal structure emplacement Eocene foreland basin magmatism mountain region oceanic lithosphere stacking subduction zone uplift Andes Argentina Chubut Repeated eastward shifts of arc magmatism in the Southern Andes: A revision to the long-term pattern of Andean uplift and magmatism |
| topic_facet |
Arc magmatism Mountain uplift Slab shallowing Synorogenic sequences asthenosphere Cretaceous crustal shortening crustal structure emplacement Eocene foreland basin magmatism mountain region oceanic lithosphere stacking subduction zone uplift Andes Argentina Chubut |
| description |
The Southern Andes have been built through the stacking of crustal sheets in discrete periods during the last 100 My. The first important shortening took place in Late Cretaceous at the time of eastward arc expansions potentially linked to two areas of subducted slab shallowings of 200 and 800 km wide respectively. These shallowings have progressed to two smaller flat slabs in Eocene times, where rather anhydrous subducted slabs generated a discontinuous arc emplaced in the foreland area at the time of mountain building. Discrete segments of the former Late Cretaceous slab shallowings would have fallen down at this time producing early slab steepening settings where within-plate products and extensional basins developed such as in the southern Chubut Province. Then Late Oligocene times coincide with the final steepening of the broad Late Cretaceous to Eocene shallow subduction zone with the emplacement of voluminous volcanic plateaux in central Patagonia and extensional basins in the hinterland zone. Lately a long quiescence period was interrupted by the development of three Miocene shallow subduction settings more than 400 km long each, evidenced by arc expansions and associated with Andean construction. Most of these areas were extensionally reactivated in the last 5 My at the time of retraction and steepening of formerly shallow subduction zones, being associated with voluminous mantle derived materials and shallow asthenospheric injection. While some of these shallow subduction configurations could be explained by subduction of highly buoyant oceanic lithosphere related to seismic ridges, in particular those of the Aluk/Farallones and Chilean ridges, other mechanisms remain more speculative. The alternation of shallow subduction zones and their steepening in the last 100 My in the Southern Andes explain location and timing of main magmatic fluxes in the arc and retroarc areas, as well as the presence of coeval foreland mountain systems east of the Main Andes. © 2011 Elsevier Ltd. |
| title |
Repeated eastward shifts of arc magmatism in the Southern Andes: A revision to the long-term pattern of Andean uplift and magmatism |
| title_short |
Repeated eastward shifts of arc magmatism in the Southern Andes: A revision to the long-term pattern of Andean uplift and magmatism |
| title_full |
Repeated eastward shifts of arc magmatism in the Southern Andes: A revision to the long-term pattern of Andean uplift and magmatism |
| title_fullStr |
Repeated eastward shifts of arc magmatism in the Southern Andes: A revision to the long-term pattern of Andean uplift and magmatism |
| title_full_unstemmed |
Repeated eastward shifts of arc magmatism in the Southern Andes: A revision to the long-term pattern of Andean uplift and magmatism |
| title_sort |
repeated eastward shifts of arc magmatism in the southern andes: a revision to the long-term pattern of andean uplift and magmatism |
| publishDate |
2011 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_08959811_v32_n4_p531_Folguera http://hdl.handle.net/20.500.12110/paper_08959811_v32_n4_p531_Folguera |
| _version_ |
1768545469940629504 |