Boron isotope variations in a single monogenetic cone: La Poruña (21°53′S, 68°30′W), Central Andes, Chile

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datacite.creatorGodoy, Benigno
datacite.creatorDeegan, Frances
datacite.creatorGonzález-Maurel, Osvaldo
datacite.creatorle-Roux, Petrus
datacite.creatorGarbe-Schönberg, Dieter
datacite.creatorRodríguez, Inés
datacite.creatorGuzmán-Marusic, Gabriela
datacite.creatorMarín, Carolina
datacite.date2023-01-13
datacite.rightsAcceso Abierto
datacite.subject.englishBoron isotopes
datacite.subject.englishCentral Andes
datacite.subject.englishCrustal assimilation
datacite.subject.englishLa Poruña
datacite.titleBoron isotope variations in a single monogenetic cone: La Poruña (21°53′S, 68°30′W), Central Andes, Chile
dc.date.accessioned2025-01-30T14:59:34Z
dc.date.available2025-01-30T14:59:34Z
dc.descriptionBenigno Godoy informa que recibió apoyo financiero del Fondo Nacional de Desarrollo Científico, Tecnológico y de Innovación Tecnológica (National Fund For Scientific Technological and Technological Innovation Development) y de los Fondos de la Comisión Nacional de Investigación Científica y Tecnológica (National Commission for Scientific and Technological Research Funds) para Centros de Investigación en Áreas Prioritarias. Frances M. Deegan informa que recibió apoyo financiero del Consejo Sueco de Investigación (Swedish Research Council) y la Universidad de Uppsala (Uppsala University). Petrus le Roux informa que recibió apoyo financiero de la Fundación Nacional de Investigación de Sudáfrica (National Research Foundation of South Africa).
dc.description.abstractenLa Poruña is a monogenetic volcano located within the Altiplano-Puna Volcanic Complex (21°-24°S) in the Central Andean subduction zone. Since crustal contamination of Andean magmas is ubiquitous, and because extensive geochemical data exist for La Poruña, we employ this volcano as a case study to examine the behavior of boron isotopes during crustal assimilation. We present whole-rock boron concentration and 11B/10B ratios (as δ11B values) for La Poruña lava samples that were prepared as nano-particulate pressed pellets. La Poruña B contents range from 14 to 20 μg/g and δ11B values range from −1.39 ± 0.54 ‰ (2σ) to +0.94 ± 0.30 ‰ (2σ), which overlap with the range of available whole-rock data for Central Andean lavas. Moreover, La Poruña δ11B values correlate negatively with 87Sr/86Sr ratios from the same samples. Since 87Sr/86Sr is a proxy for crustal contamination at La Poruña, the data lead us to suggest that La Poruña magmas assimilated a low-δ11B, high 87Sr/86Sr component such as Andean continental crust. Mixing models based on B and Sr isotopes support a broadly two-step magma evolution for La Poruña. In step 1, mantle-derived primary melts interacted with boron-rich slab-derived fluids with high δ11B values, which yielded subduction-modified parental magmas with ca. 3 μg/g B and relatively high δ11B values. In step 2, the high δ11B parental magmas ascended through the crust where they assimilated up to 20% crustal material, which further modified their δ11B values and 87Sr/86Sr ratios. In comparison to available regional values for B and δ11B, it appears that La Poruña and nearby volcanic centers shared a similar source and magmatic history, whereas volcanoes south of 23°S differ. We stress, however, that deconvolving the roles of various subduction and crustal inputs in the Central Andes would require further studies on individual volcanoes along the arc.
dc.identifier.doi10.1016/j.lithos.2023.107030
dc.identifier.urihttps://repositoriodigital.uct.cl/handle/10925/6168
dc.language.isoen
dc.publisherElsevier
dc.rightsObra bajo licencia Creative Commons 4.0
dc.sourceLithos
oaire.citationTitleArtículo
oaire.citationVolume440-441
oaire.fundingReferenceAgencia InterNacional de Investigación y Desarrollo (ANID)
oaire.fundingReferenceNational Research Foundation South Africa
oaire.resourceTypeArtículo
uct.catalogadormlj
uct.departamentoDepartamento de Obras Civiles y Geología
uct.facultadFacultad de Ingeniería
uct.indizacionSCOPUS
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