Early Cambrian U-Pb zircon age and Hf-isotope data from the Guasayán pluton, Sierras Pampeanas, Argentina: implications for the northwestern boundary of the Pampean arc
An Early Cambrian pluton, known as the Guasayan pluton, has been identified in the central area of Sierra de Guasayan, northwestern Argentina. A U-Pb zircon Concordia age of 533±4 Ma was obtained by LA-MC-ICP-MS and represents the first report of robustly dated Early Cambrian magmatism for the north...
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Servicio Nacional de Geología y Minería (SERNAGEOMIN)
2016
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oai:scielo:S0718-710620160001000082016-07-29Early Cambrian U-Pb zircon age and Hf-isotope data from the Guasayán pluton, Sierras Pampeanas, Argentina: implications for the northwestern boundary of the Pampean arcDahlquist,Juan AVerdecchia,Sebastián OBaldo,Edgardo GBasei,Miguel A.SAlasino,Pablo HUrán,Gimena ARapela,Carlos WNeto,Mario da Costa CamposZandomeni,Priscila S U-Pb Geochronology Hf isotopes Pampean granites Sierra de Guasayan An Early Cambrian pluton, known as the Guasayan pluton, has been identified in the central area of Sierra de Guasayan, northwestern Argentina. A U-Pb zircon Concordia age of 533±4 Ma was obtained by LA-MC-ICP-MS and represents the first report of robustly dated Early Cambrian magmatism for the northwestern Sierras Pampeanas. The pluton was emplaced in low-grade metasedimentary rocks and its magmatic assemblage consists of K-feldspar (phenocrysts)+plagioclase+quartz+biotite, with zircon, apatite, ilmenite, magnetite and monazite as accessory minerals. Geochemically, the granitic rock is a metaluminous subalkaline felsic granodiorite with SiO2=69.24%, Na2O+K2O=7.08%, CaO=2.45%, Na2O/ K2O=0.71 and FeO/MgO=3.58%. Rare earth element patterns show moderate slope (LaN/YbN=8.05) with a slightly negative Eu anomalies (Eu/Eu*=0.76). We report the first in situ Hf isotopes data (εHft=-0.12 to -4.76) from crystallized zircons in the Early Cambrian granites of the Sierras Pampeanas, helping to constrain the magma source and enabling comparison with other Pampean granites. The Guasayan pluton might provide a link between Early Cambrian magmatism of the central Sierras Pampeanas and that of the Eastern Cordillera, contributing to define the western boundary of the Pampean paleo-arc.info:eu-repo/semantics/openAccessServicio Nacional de Geología y Minería (SERNAGEOMIN)Andean geology v.43 n.1 20162016-01-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-71062016000100008en10.5027/andgeoV43n1-a08 |
| institution |
Scielo Chile |
| collection |
Scielo Chile |
| language |
English |
| topic |
U-Pb Geochronology Hf isotopes Pampean granites Sierra de Guasayan |
| spellingShingle |
U-Pb Geochronology Hf isotopes Pampean granites Sierra de Guasayan Dahlquist,Juan A Verdecchia,Sebastián O Baldo,Edgardo G Basei,Miguel A.S Alasino,Pablo H Urán,Gimena A Rapela,Carlos W Neto,Mario da Costa Campos Zandomeni,Priscila S Early Cambrian U-Pb zircon age and Hf-isotope data from the Guasayán pluton, Sierras Pampeanas, Argentina: implications for the northwestern boundary of the Pampean arc |
| description |
An Early Cambrian pluton, known as the Guasayan pluton, has been identified in the central area of Sierra de Guasayan, northwestern Argentina. A U-Pb zircon Concordia age of 533±4 Ma was obtained by LA-MC-ICP-MS and represents the first report of robustly dated Early Cambrian magmatism for the northwestern Sierras Pampeanas. The pluton was emplaced in low-grade metasedimentary rocks and its magmatic assemblage consists of K-feldspar (phenocrysts)+plagioclase+quartz+biotite, with zircon, apatite, ilmenite, magnetite and monazite as accessory minerals. Geochemically, the granitic rock is a metaluminous subalkaline felsic granodiorite with SiO2=69.24%, Na2O+K2O=7.08%, CaO=2.45%, Na2O/ K2O=0.71 and FeO/MgO=3.58%. Rare earth element patterns show moderate slope (LaN/YbN=8.05) with a slightly negative Eu anomalies (Eu/Eu*=0.76). We report the first in situ Hf isotopes data (εHft=-0.12 to -4.76) from crystallized zircons in the Early Cambrian granites of the Sierras Pampeanas, helping to constrain the magma source and enabling comparison with other Pampean granites. The Guasayan pluton might provide a link between Early Cambrian magmatism of the central Sierras Pampeanas and that of the Eastern Cordillera, contributing to define the western boundary of the Pampean paleo-arc. |
| author |
Dahlquist,Juan A Verdecchia,Sebastián O Baldo,Edgardo G Basei,Miguel A.S Alasino,Pablo H Urán,Gimena A Rapela,Carlos W Neto,Mario da Costa Campos Zandomeni,Priscila S |
| author_facet |
Dahlquist,Juan A Verdecchia,Sebastián O Baldo,Edgardo G Basei,Miguel A.S Alasino,Pablo H Urán,Gimena A Rapela,Carlos W Neto,Mario da Costa Campos Zandomeni,Priscila S |
| author_sort |
Dahlquist,Juan A |
| title |
Early Cambrian U-Pb zircon age and Hf-isotope data from the Guasayán pluton, Sierras Pampeanas, Argentina: implications for the northwestern boundary of the Pampean arc |
| title_short |
Early Cambrian U-Pb zircon age and Hf-isotope data from the Guasayán pluton, Sierras Pampeanas, Argentina: implications for the northwestern boundary of the Pampean arc |
| title_full |
Early Cambrian U-Pb zircon age and Hf-isotope data from the Guasayán pluton, Sierras Pampeanas, Argentina: implications for the northwestern boundary of the Pampean arc |
| title_fullStr |
Early Cambrian U-Pb zircon age and Hf-isotope data from the Guasayán pluton, Sierras Pampeanas, Argentina: implications for the northwestern boundary of the Pampean arc |
| title_full_unstemmed |
Early Cambrian U-Pb zircon age and Hf-isotope data from the Guasayán pluton, Sierras Pampeanas, Argentina: implications for the northwestern boundary of the Pampean arc |
| title_sort |
early cambrian u-pb zircon age and hf-isotope data from the guasayán pluton, sierras pampeanas, argentina: implications for the northwestern boundary of the pampean arc |
| publisher |
Servicio Nacional de Geología y Minería (SERNAGEOMIN) |
| publishDate |
2016 |
| url |
http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-71062016000100008 |
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