Equivocal carbonatite markers in the mantle xenoliths of the Patagonia backarc: the Gobernador Gregores case (Santa Cruz Province, Argentina)

Amphibole ± phlogopite ± apatite-bearing mantle xenoliths at Gobernador Gregores display modal, bulk-rock and phase geochemical characteristics held as indicators of carbonatitic metasomatism. However, part of these xenoliths has high TiO₂/Al₂O3 and those displaying the most pronounced carbonatitic...

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Detalles Bibliográficos
Autores principales: Rivalenti, Giorgio, Zanetti, Alberto, Mazzucchelli, Maurizio, Vannucci, Riccardo, Cingolani, Carlos Alberto
Formato: Articulo
Lenguaje:Inglés
Publicado: 2004
Materias:
Ciencias Naturales
High Field Strength Element
Geochemical Variation
Light Rare Earth Element
Metasomatic Agent
Modal Trend
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/134912
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-134912
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Naturales
High Field Strength Element
Geochemical Variation
Light Rare Earth Element
Metasomatic Agent
Modal Trend
spellingShingle Ciencias Naturales
High Field Strength Element
Geochemical Variation
Light Rare Earth Element
Metasomatic Agent
Modal Trend
Rivalenti, Giorgio
Zanetti, Alberto
Mazzucchelli, Maurizio
Vannucci, Riccardo
Cingolani, Carlos Alberto
Equivocal carbonatite markers in the mantle xenoliths of the Patagonia backarc: the Gobernador Gregores case (Santa Cruz Province, Argentina)
topic_facet Ciencias Naturales
High Field Strength Element
Geochemical Variation
Light Rare Earth Element
Metasomatic Agent
Modal Trend
description Amphibole ± phlogopite ± apatite-bearing mantle xenoliths at Gobernador Gregores display modal, bulk-rock and phase geochemical characteristics held as indicators of carbonatitic metasomatism. However, part of these xenoliths has high TiO₂/Al₂O3 and those displaying the most pronounced carbonatitic geochemical markers modally trend towards harzburgite. Bulk-rock, clinopyroxene and amphibole show Zr, Hf and Ti negative anomalies, which increase at decreasing Na₂O and high field strength elements (HFSE) concentrations. Steady variation trends between xenoliths which have and do not have carbonatitic characteristics suggest a control by reactive porous flow of only one agent, inferred to be initially a ne-normative hydrous basalt (because of the presence of wehrlites) evolving towards silica saturation. Variation trends exhibit cusps when amphibole appears in the mode. Appearance of amphibole may explain the Ti anomaly variations, but not those of Zr and Hf. Numerical modelling [Plate Model (Vernieres et al. in J Geophys Res 102:24771–24784, 1997)] gives results consistent with the observed geochemical features by assuming the presence of loveringite. Modest HFSE anomalies in the infiltrating melt may be acquired during percolation in the garnet-facies.
format Articulo
Articulo
author Rivalenti, Giorgio
Zanetti, Alberto
Mazzucchelli, Maurizio
Vannucci, Riccardo
Cingolani, Carlos Alberto
author_facet Rivalenti, Giorgio
Zanetti, Alberto
Mazzucchelli, Maurizio
Vannucci, Riccardo
Cingolani, Carlos Alberto
author_sort Rivalenti, Giorgio
title Equivocal carbonatite markers in the mantle xenoliths of the Patagonia backarc: the Gobernador Gregores case (Santa Cruz Province, Argentina)
title_short Equivocal carbonatite markers in the mantle xenoliths of the Patagonia backarc: the Gobernador Gregores case (Santa Cruz Province, Argentina)
title_full Equivocal carbonatite markers in the mantle xenoliths of the Patagonia backarc: the Gobernador Gregores case (Santa Cruz Province, Argentina)
title_fullStr Equivocal carbonatite markers in the mantle xenoliths of the Patagonia backarc: the Gobernador Gregores case (Santa Cruz Province, Argentina)
title_full_unstemmed Equivocal carbonatite markers in the mantle xenoliths of the Patagonia backarc: the Gobernador Gregores case (Santa Cruz Province, Argentina)
title_sort equivocal carbonatite markers in the mantle xenoliths of the patagonia backarc: the gobernador gregores case (santa cruz province, argentina)
publishDate 2004
url http://sedici.unlp.edu.ar/handle/10915/134912
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