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dc.contributor.author
Maro, Guadalupe  
dc.contributor.author
Caffe, Pablo Jorge  
dc.contributor.author
Romer, Rolf L  
dc.contributor.author
Trumbull, Robert B  
dc.date.available
2018-05-31T21:10:23Z  
dc.date.issued
2017-08  
dc.identifier.citation
Maro, Guadalupe; Caffe, Pablo Jorge; Romer, Rolf L; Trumbull, Robert B; Neogene Mafic Magmatism in the Northern Puna Plateau, Argentina: Generation and Evolution of a Back-arc Volcanic Suite; Oxford University Press; Journal Of Petrology; 58; 8; 8-2017; 1591-1617  
dc.identifier.issn
0022-3530  
dc.identifier.uri
http://hdl.handle.net/11336/46929  
dc.description.abstract
Neogene back-arc mafic volcanism in the northern Puna Plateau produced a suite of mainly high-Mg, calc-alkaline, basaltic andesites to andesites that form small scoria cones and lava fields. We present the first comprehensive geochemical study of the mafic suite in the northern Puna that complements work on similar rocks from the southern Puna Plateau. The emphasis is on magma genesis and evolution in both areas, and on a combined interpretation of the two regional datasets in the geodynamic context of back-arc magmatism in the central Andes. The results from the northern Puna suite (bulk-rock and mineral compositions, thermobarometry and radiogenic isotope ratios) are consistent with a predominantly asthenospheric source for the mafic magmas, with variable but locally significant contamination by crustal material. Quantifying the crustal and mantle input fails in most cases because the data display contradictory features, such as high compatible element contents (Mg, Ni, Cr) paired with moderate contents of silica and incompatible lithophile elements that defy classical models of magma mixing, fractionation and assimilation. We suggest that magma evolution involved selective assimilation during turbulent flow, probably at more than one level in the crust. Comparison with the southern Puna mafic suite reveals many features in common (high magma temperatures, textural evidence of rapid magma ascent and cooling, assimilation of crust at different depths). However, the volume of erupted magma is greater in the south than in the north and the volcanism in the south is slightly younger. There is much compositional overlap between the two regions, but the southern Puna suite extends to more primitive compositions. These differences suggest a stronger crustal influence in the northern Puna andesites, which we suggest is due to the presence of an extended upper-crustal melt zone associated with the Altiplano?Puna ignimbrite province. Radiogenic Sr and Nd isotope data from both suites define two diverging trends of variation with MgO that can be explained with a crustal component common to both trends, similar to the silicic ignimbrites, and two contrasting mantle components. The more common and regionally more widespread of the two mantle components (also seen in the frontal arc magmas) has <sup>87</sup>Sr/<sup>86</sup>Sr and <sup>143</sup>Nd/<sup>144</sup>Nd values of 0·705 and 0·5126, respectively, which we attribute to an asthenospheric source enriched by subduction erosion. The less common of the two has Sr and Nd initial ratios (0·708 and 0·51235) that we attribute to melting or assimilation of enriched lithosphere. This component has been found only in the northern Puna and it may have an origin in delaminated lithosphere.  
dc.format
application/pdf  
dc.language.iso
eng  
dc.publisher
Oxford University Press  
dc.rights
info:eu-repo/semantics/restrictedAccess  
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/  
dc.subject
High-Mg Andesite  
dc.subject
Puna Plateau  
dc.subject
Central Andes  
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Monogenetic Volcanism  
dc.subject
Mafic Volcanism  
dc.subject.classification
Meteorología y Ciencias Atmosféricas  
dc.subject.classification
Ciencias de la Tierra y relacionadas con el Medio Ambiente  
dc.subject.classification
CIENCIAS NATURALES Y EXACTAS  
dc.title
Neogene Mafic Magmatism in the Northern Puna Plateau, Argentina: Generation and Evolution of a Back-arc Volcanic Suite  
dc.type
info:eu-repo/semantics/article  
dc.type
info:ar-repo/semantics/artículo  
dc.type
info:eu-repo/semantics/publishedVersion  
dc.date.updated
2018-04-24T15:16:27Z  
dc.journal.volume
58  
dc.journal.number
8  
dc.journal.pagination
1591-1617  
dc.journal.pais
Reino Unido  
dc.journal.ciudad
Oxford  
dc.description.fil
Fil: Maro, Guadalupe. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina  
dc.description.fil
Fil: Caffe, Pablo Jorge. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina  
dc.description.fil
Fil: Romer, Rolf L. German Research Centre for Geosciences; Alemania  
dc.description.fil
Fil: Trumbull, Robert B. German Research Centre for Geosciences; Alemania  
dc.journal.title
Journal Of Petrology  
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/http://academic.oup.com/petrology/article/58/8/1591/4460104  
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1093/petrology/egx066