Artículo
A combined zircon Hf isotope and whole-rock Nd and Sr isotopes study of Carboniferous A-type granites, Sierras Pampeanas of Argentina
Dahlquist, Juan Andrés
; Galindo Francisco, Carmen; Morales Camera, Matías Martín
; Moreno Moreno, Juan Antonio
; Alasino, Pablo Horacio
; Stipp Basei, Miguel Angelo; Macchioli Grande, Marcos Simón
Fecha de publicación:
06/2020
Editorial:
Pergamon-Elsevier Science Ltd
Revista:
Journal of South American Earth Sciences
ISSN:
0895-9811
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
We report new whole-rock Nd and Sr isotope data for two strongly peraluminous and one slightly peraluminous Carboniferous A-type granitic plutons in the eastern Sierras Pampeanas of Argentina. Our study also integrates previous petrological and geochemical information with in situ U–Pb and Hf isotope data from magmatic and inherited zircon. Strongly peraluminous samples have pronounced negative εNdt values (−7.6 and −7.0) and very high (87Sr/86Sr)t values (0.728778 and 0.747092). These are similar to isotope compositions reported for the Puncoviscan Series, a metasedimentary sequence metamorphosed during the Lower Cambrian and intruded by these granites. Nd and Sr isotope data for the slightly peraluminous sample (εNdt = −3.5 and 87Sr/86Srt = 0.708074), together with previously reported petrological and geochemical data, indicate that the basement of the Sierras de Córdoba participated in the generation of the parental magma. The new data are not easily reconciled with the positive zircon εHft values previously reported for these samples, which suggest dominantly juvenile material in the source. We propose that Hf was transferred from inherited zircon toward the magmatic rim, without complete isotopic homogenization with the magma, as has been hypothesized in previous works. Our results reveal that the indiscriminate use of Hf databases can lead to false inference of crustal growth by mantle addition through time and misleading comparisons between granitic rocks worldwide.
Palabras clave:
ZIRCON HF ISOTOPES
,
ND AND SR ISOTOPES
,
A-TYPE GRANITES
,
SIERRAS PAMPEANAS
Archivos asociados
Licencia
Identificadores
Colecciones
Articulos(CICTERRA)
Articulos de CENTRO DE INVEST.EN CS.DE LA TIERRA
Articulos de CENTRO DE INVEST.EN CS.DE LA TIERRA
Articulos(CRILAR)
Articulos de CENTRO REGIONAL DE INV. CIENTIFICAS Y TRANSFERENCIA TECNOLOGICA DE ANILLACO
Articulos de CENTRO REGIONAL DE INV. CIENTIFICAS Y TRANSFERENCIA TECNOLOGICA DE ANILLACO
Citación
Dahlquist, Juan Andrés; Galindo Francisco, Carmen; Morales Camera, Matías Martín; Moreno Moreno, Juan Antonio; Alasino, Pablo Horacio; et al.; A combined zircon Hf isotope and whole-rock Nd and Sr isotopes study of Carboniferous A-type granites, Sierras Pampeanas of Argentina; Pergamon-Elsevier Science Ltd; Journal of South American Earth Sciences; 100; 6-2020; 1-12
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