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dc.contributor.author
Mazzuoli, R.  
dc.contributor.author
Vezzoli, L.  
dc.contributor.author
Omarini, Ricardo Hector  
dc.contributor.author
Acocella, V.  
dc.contributor.author
Gioncada, A.  
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Matteini, Massimo  
dc.contributor.author
Dini, A.  
dc.contributor.author
Guillou, H.  
dc.contributor.author
Hauser, Natalia  
dc.contributor.author
Uttini, A.  
dc.contributor.author
Scaillet, S.  
dc.date.available
2019-02-20T20:37:07Z  
dc.date.issued
2008-12  
dc.identifier.citation
Mazzuoli, R.; Vezzoli, L.; Omarini, Ricardo Hector; Acocella, V.; Gioncada, A.; et al.; Miocene magmatism and tectonics of the easternmost sector of the Calama-Olacapato-El Toro fault system in Central Andes at ∼24°S: Insights into the evolution of the Eastern Cordillera; Geological Society of America; Geological Society of America Bulletin; 120; 11-12; 12-2008; 1493-1517  
dc.identifier.issn
0016-7606  
dc.identifier.uri
http://hdl.handle.net/11336/70564  
dc.description.abstract
The Miocene Las Burras - Almagro - El Toro magmatic complex lies ∼300 km to the east of the Central Andes volcanic arc, in the easternmost sector of the transverse Calama - Olacapato - El Toro fault zone. The magmatic rocks of the Las Burras - Almagro - El Toro complex comprise a monzogabbro to monzogranite laccolith like intrusion and basaltic andesite to dacite volcanic rocks that include sevenlithostratigraphic members. New Rb-Sr dates indicate that the intrusive rocks are ca. 14 Ma, and K-Ar dates suggest emplacement ages of ca. 12.8-6.4 Ma for the volcanic rocks. The emplacement of the intrusion was controlled by N-S - striking strike-slip faults in a context of oblique convergence; the volcanism, which occurred along WNW-ESE - and N-S - striking extensional faults, relates to the Calama - Olacapato - El Toro fault zone. Two magmatic phases were recognized. Intrusive and volcanic rocks of the older magmatic phase (ca. 14-13 Ma) are characterized by Ba/Nb (7-14), La/Ta (11-18), and isotopic ratios (87Sr/86Sr: 0.704339-0.705281, 143Nd/144Nd: 0.512713-0.512598), which are intraplate characteristics. The source of the older magmas was isotopically depleted lithospheric mantle rich in K, Rb, and Th. Energy constrained-assimilation and fractional crystallization (EC-AFC) modeling indicates that fractional crystallization and crustal assimilation moderately modified magma composition during its residence in the crust. The products of the younger magmatic phase (ca. 11-6 Ma) have higher Ba/Nb (24-42) and La/Ta (24-30) and 87Sr/86Sr (0.706738-0.708729) and lower 143Nd/144Nd (0.512433-0.512360). The results of EC-AFC modeling exclude a significant role for the upper crust in the generation of the most primitive magmas of this phase. Their compositions can be explained by (1) contamination of the primary magmas having originated in a depleted mantle with a mafic crust, or (2) the contribution of isotopically enriched mantle zones. Shallow differentiation and moderate contamination by continental crust can explain the composition of the intermediate and evolved products of the younger phase. The variation of the magma source characteristics at 11 Ma is discussed in the frame of the complex geo-dynamical setting in this region.  
dc.format
application/pdf  
dc.language.iso
eng  
dc.publisher
Geological Society of America  
dc.rights
info:eu-repo/semantics/openAccess  
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/  
dc.subject
Backarc Magmatism  
dc.subject
Central Andes  
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Eastern Cordillera  
dc.subject
Geochronology  
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Structural Geology  
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Volcanic Stratigraphy  
dc.subject.classification
Geología  
dc.subject.classification
Ciencias de la Tierra y relacionadas con el Medio Ambiente  
dc.subject.classification
CIENCIAS NATURALES Y EXACTAS  
dc.title
Miocene magmatism and tectonics of the easternmost sector of the Calama-Olacapato-El Toro fault system in Central Andes at ∼24°S: Insights into the evolution of the Eastern Cordillera  
dc.type
info:eu-repo/semantics/article  
dc.type
info:ar-repo/semantics/artículo  
dc.type
info:eu-repo/semantics/publishedVersion  
dc.date.updated
2019-02-12T17:09:41Z  
dc.journal.volume
120  
dc.journal.number
11-12  
dc.journal.pagination
1493-1517  
dc.journal.pais
Estados Unidos  
dc.journal.ciudad
Boulder  
dc.description.fil
Fil: Mazzuoli, R.. Università degli Studi di Pisa; Italia  
dc.description.fil
Fil: Vezzoli, L.. Università Degli Studi Dell'insubria; Italia  
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Fil: Omarini, Ricardo Hector. Universidad Nacional de Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina  
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Fil: Acocella, V.. Università Degli Studi Roma Tre; Italia  
dc.description.fil
Fil: Gioncada, A.. Università degli Studi di Pisa; Italia  
dc.description.fil
Fil: Matteini, Massimo. Universidade do Brasília; Brasil  
dc.description.fil
Fil: Dini, A.. Istituto Di Geoscienze E Georisorse, Sezione Di Pisa; Italia  
dc.description.fil
Fil: Guillou, H.. Centre National de la Recherche Scientifique. Laboratoire des Sciences du Climat et de l'Environnement ; Francia  
dc.description.fil
Fil: Hauser, Natalia. Universidad Nacional de Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina  
dc.description.fil
Fil: Uttini, A.. Università Degli Studi Dell'insubria; Italia  
dc.description.fil
Fil: Scaillet, S.. Centre National de la Recherche Scientifique. Laboratoire des Sciences du Climat et de l'Environnement ; Francia  
dc.journal.title
Geological Society of America Bulletin  
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1130/B26109.1  
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/https://pubs.geoscienceworld.org/gsa/gsabulletin/article/120/11-12/1493-1517/2247