Geochemistry, U-Pb SHRIMP zircon dating and Hf isotopes of the Gondwanan magmatism in NW Argentina: petrogenesis and geodynamic implications

We have carried out zircon U-Pb SHRIMP dating and Hf isotope determinations as well as geochemical analyses on three plutonic units of Gondwanan magmatism that crop out in NW Argentina. Two episodes of different age and genesis have been identified. The older one includes gabbros and diorites (Río G...

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Autores principales:	Poma,Stella, Zappettini,Eduardo O, Quenardelle,Sonia, Santos,João O, Koukharsky,Magdalena, Belousova,Elena, McNaughton,Neil
Lenguaje:	English
Publicado:	Servicio Nacional de Geología y Minería (SERNAGEOMIN) 2014
Materias:	Gondwanan magmatism Geochemistry U-Pb SHRIMP dating Lu-Hf isotope NW Argentina
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-71062014000200001
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spelling	oai:scielo:S0718-710620140002000012015-10-30Geochemistry, U-Pb SHRIMP zircon dating and Hf isotopes of the Gondwanan magmatism in NW Argentina: petrogenesis and geodynamic implicationsPoma,StellaZappettini,Eduardo OQuenardelle,SoniaSantos,João OKoukharsky,MagdalenaBelousova,ElenaMcNaughton,Neil Gondwanan magmatism Geochemistry U-Pb SHRIMP dating Lu-Hf isotope NW Argentina We have carried out zircon U-Pb SHRIMP dating and Hf isotope determinations as well as geochemical analyses on three plutonic units of Gondwanan magmatism that crop out in NW Argentina. Two episodes of different age and genesis have been identified. The older one includes gabbros and diorites (Río Grande Unit) of 267±3 Ma and granitoids (belonging to the Llullaillaco Unit) of 263±1 Ma (late Permian, Guadalupian); the parent magmas were generated in an intraplate environment and derived from an enriched mantle but were subsequently contaminated by crustal components. The younger rocks are granodiorites with arc signature (Chuculaqui Unit) and an age of 247±2 Ma (middle Triassic-Anisian). Hf isotope signature of the units indicates mantle sources as well as crustal components. Hf model ages obtained are consistent with the presence of crustal Mesoproterozoic (mainly Ectasian to Calymnian (T DM(c)=1.24 to 1.44 Ga-negative εHf m) and juvenile Cryogenian sources (T DM=0.65 to 0.79 Ga-positive eHf (T)), supporting the idea of a continuous, mostly Mesoproterozoic, basement under the Central Andes, as an extension of the Arequipa-Antofalla massif. The tectonic setting and age of the Gondwanan magmatism in NW Argentina allow to differentiate: a. Permian intra-plate magmatism developed under similar conditions to the upper section of the Choiyoi magmatism exposed in the Frontal Cordillera and San Rafael Block, Argentina; b. Triassic magmatism belonging to a poorly known subduction-related magmatic arc segment of mostly NS trend with evidence of porphyry type mineralization in Chile, allowing to extend this metallotect into Argentina.info:eu-repo/semantics/openAccessServicio Nacional de Geología y Minería (SERNAGEOMIN)Andean geology v.41 n.2 20142014-05-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-71062014000200001en10.5027/andgeoV41n2-a01
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Gondwanan magmatism Geochemistry U-Pb SHRIMP dating Lu-Hf isotope NW Argentina
spellingShingle	Gondwanan magmatism Geochemistry U-Pb SHRIMP dating Lu-Hf isotope NW Argentina Poma,Stella Zappettini,Eduardo O Quenardelle,Sonia Santos,João O Koukharsky,Magdalena Belousova,Elena McNaughton,Neil Geochemistry, U-Pb SHRIMP zircon dating and Hf isotopes of the Gondwanan magmatism in NW Argentina: petrogenesis and geodynamic implications
description	We have carried out zircon U-Pb SHRIMP dating and Hf isotope determinations as well as geochemical analyses on three plutonic units of Gondwanan magmatism that crop out in NW Argentina. Two episodes of different age and genesis have been identified. The older one includes gabbros and diorites (Río Grande Unit) of 267±3 Ma and granitoids (belonging to the Llullaillaco Unit) of 263±1 Ma (late Permian, Guadalupian); the parent magmas were generated in an intraplate environment and derived from an enriched mantle but were subsequently contaminated by crustal components. The younger rocks are granodiorites with arc signature (Chuculaqui Unit) and an age of 247±2 Ma (middle Triassic-Anisian). Hf isotope signature of the units indicates mantle sources as well as crustal components. Hf model ages obtained are consistent with the presence of crustal Mesoproterozoic (mainly Ectasian to Calymnian (T DM(c)=1.24 to 1.44 Ga-negative εHf m) and juvenile Cryogenian sources (T DM=0.65 to 0.79 Ga-positive eHf (T)), supporting the idea of a continuous, mostly Mesoproterozoic, basement under the Central Andes, as an extension of the Arequipa-Antofalla massif. The tectonic setting and age of the Gondwanan magmatism in NW Argentina allow to differentiate: a. Permian intra-plate magmatism developed under similar conditions to the upper section of the Choiyoi magmatism exposed in the Frontal Cordillera and San Rafael Block, Argentina; b. Triassic magmatism belonging to a poorly known subduction-related magmatic arc segment of mostly NS trend with evidence of porphyry type mineralization in Chile, allowing to extend this metallotect into Argentina.
author	Poma,Stella Zappettini,Eduardo O Quenardelle,Sonia Santos,João O Koukharsky,Magdalena Belousova,Elena McNaughton,Neil
author_facet	Poma,Stella Zappettini,Eduardo O Quenardelle,Sonia Santos,João O Koukharsky,Magdalena Belousova,Elena McNaughton,Neil
author_sort	Poma,Stella
title	Geochemistry, U-Pb SHRIMP zircon dating and Hf isotopes of the Gondwanan magmatism in NW Argentina: petrogenesis and geodynamic implications
title_short	Geochemistry, U-Pb SHRIMP zircon dating and Hf isotopes of the Gondwanan magmatism in NW Argentina: petrogenesis and geodynamic implications
title_full	Geochemistry, U-Pb SHRIMP zircon dating and Hf isotopes of the Gondwanan magmatism in NW Argentina: petrogenesis and geodynamic implications
title_fullStr	Geochemistry, U-Pb SHRIMP zircon dating and Hf isotopes of the Gondwanan magmatism in NW Argentina: petrogenesis and geodynamic implications
title_full_unstemmed	Geochemistry, U-Pb SHRIMP zircon dating and Hf isotopes of the Gondwanan magmatism in NW Argentina: petrogenesis and geodynamic implications
title_sort	geochemistry, u-pb shrimp zircon dating and hf isotopes of the gondwanan magmatism in nw argentina: petrogenesis and geodynamic implications
publisher	Servicio Nacional de Geología y Minería (SERNAGEOMIN)
publishDate	2014
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-71062014000200001
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Geochemistry, U-Pb SHRIMP zircon dating and Hf isotopes of the Gondwanan magmatism in NW Argentina: petrogenesis and geodynamic implications

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