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dc.contributor.author
Bertotto, Gustavo Walter  
dc.contributor.author
Mazzucchelli, Maurizio  
dc.contributor.author
Zanetti, Alberto  
dc.contributor.author
Vannucci, Riccardo  
dc.date.available
2017-07-05T17:36:00Z  
dc.date.issued
2013-04  
dc.identifier.citation
Bertotto, Gustavo Walter; Mazzucchelli, Maurizio; Zanetti, Alberto; Vannucci, Riccardo; Petrology and geochemistry of the back-arc lithospheric mantle beneath eastern Payunia (La Pampa, Argentina): evidence from Agua Poca peridotite xenoliths; Geochemical Society of Japan; Geochemical Journal; 47; 2; 4-2013; 219-234  
dc.identifier.issn
0016-7002  
dc.identifier.uri
http://hdl.handle.net/11336/19603  
dc.description.abstract
This paper presents the results of new petrochemical studies carried out on mantle xenoliths hosted in Pleistocene basaltic rocks from the Agua Poca volcano in central-western Argentina. Mantle xenoliths studied are shown to be mainly anhydrous spinel lherzolites with minor amounts of harzburgite and banded pyroxenite, showing highly variable equilibrium temperatures ranging from 820°C to 1030°C at 1.0 to 2.0 GPa. This constitutes evidence that the mantle xenoliths are representative of a large portion of the lithospheric mantle column and that the geothermal gradient is not very elevated as reported in some other Patagonian provinces. Geochemical characteristics of clinopyroxene in the mantle xenoliths allow classification into two groups; Groups 1 and 2. Group 1 contains most of the lherzolites and has light-REE depletion, with slightly positive anomalies of Eu in some samples and extreme Nb and Ta depletion. Group 2 consists of two harzburgitic samples, has flat REE patterns with lower Sm to Lu concentrations, with enriched Sr and negative HFSE anomalies. Based on mineral and residua compositions estimated assuming equilibrium with clinopyroxenes, Group 1 can be considered to be refractory residua after up to 7%, non-modal, near-fractional melting of a spinel-facies Primitive Mantle. Group 2 can be considered to be after ca. 13% of partial melting. It is inferred that partial melting events in the lithospheric mantle beneath the Agua Poca occurred in different ages since the Proterozoic, but compared with Group 1, the metasomatic overprint is dominant in Group 2 mantle xenoliths. The calculated melt compositions from Group 2 are interpreted to be transient liquid compositions developed during melt-peridotite interaction, and are different from the host alkaline basalts. The HFSE-depleted composition estimated for the rising melt suggests the presence of a slab-derived component, although the possibility cannot be disregarded (on the basis of present data) that such a geochemical feature is due to segregation of HFSE-bearing minerals during the interaction with the peridotite. Thus, we attribute the metasomatic agent to a basaltic melt and to a minor amount of slab-derived fluids.  
dc.format
application/pdf  
dc.language.iso
eng  
dc.publisher
Geochemical Society of Japan  
dc.rights
info:eu-repo/semantics/openAccess  
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/  
dc.subject
Mantle Xenoliths  
dc.subject
Fractional Melting  
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Mantle Metasomatism  
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Depleted Mantle Reservoir  
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Argentina  
dc.subject.classification
Geología  
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Ciencias de la Tierra y relacionadas con el Medio Ambiente  
dc.subject.classification
CIENCIAS NATURALES Y EXACTAS  
dc.title
Petrology and geochemistry of the back-arc lithospheric mantle beneath eastern Payunia (La Pampa, Argentina): evidence from Agua Poca peridotite xenoliths  
dc.type
info:eu-repo/semantics/article  
dc.type
info:ar-repo/semantics/artículo  
dc.type
info:eu-repo/semantics/publishedVersion  
dc.date.updated
2017-06-29T13:57:39Z  
dc.identifier.eissn
1880-5973  
dc.journal.volume
47  
dc.journal.number
2  
dc.journal.pagination
219-234  
dc.journal.pais
Japón  
dc.journal.ciudad
Tokio  
dc.description.fil
Fil: Bertotto, Gustavo Walter. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina  
dc.description.fil
Fil: Mazzucchelli, Maurizio. Università di Modena e Reggio Emilia. Dipartimento di Scienze Chimiche e Geologiche; Italia  
dc.description.fil
Fil: Zanetti, Alberto. Università di Pavia. Istituto di Geoscienze e Georisorse; Italia. Consiglio Nazionale delle Ricerche; Italia  
dc.description.fil
Fil: Vannucci, Riccardo. Università di Pavia. Dipartamento di Scienze della Terra; Italia  
dc.journal.title
Geochemical Journal  
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/http://www.terrapub.co.jp/journals/GJ/abstract/4702/47020219.html