A deformed alkaline igneous rock-carbonatite complex from the Western Sierras Pampeanas, Argentina: Evidence for late Neoproterozoic opening of the Clymene Ocean?

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dc.contributor.authorCasquet, Cesar
dc.contributor.authorPankhurst, Robert J
dc.contributor.authorGalindo, Carmen
dc.contributor.authorRapela, Carlos W
dc.contributor.authorFanning, Christopher
dc.contributor.authorBaldo, Edgardo
dc.contributor.authorDahlquist, Juan A.
dc.contributor.authorGonzalez-Casado, Jose M
dc.contributor.authorColombo, Fernando
dc.date.accessioned2015-12-08T22:40:02Z
dc.date.issued2008
dc.date.updated2015-12-08T10:20:13Z
dc.description.abstractA deformed ca. 570 Ma syenite-carbonatite body is reported from a Grenville-age (1.0-1.2 Ga) terrane in the Sierra de Maz, one of the Western Sierras Pampeanas of Argentina. This is the first recognition of such a rock assemblage in the basement of the Central Andes. The two main lithologies are coarse-grained syenite (often nepheline-bearing) and enclave-rich fine-grained foliated biotite-calcite carbonatite. Samples of carbonatite and syenite yield an imprecise whole rock Rb-Sr isochron age of 582 ± 60 Ma (MSWD = 1.8; Sri = 0.7029); SHRIMP U-Pb spot analysis of syenite zircons shows a total range of 206Pb-238U ages between 433 and 612 Ma, with a prominent peak at 560-580 Ma defined by homogeneous zircon areas. Textural interpretation of the zircon data, combined with the constraint of the Rb-Sr data suggest that the carbonatite complex formed at ca. 570 Ma. Further disturbance of the U-Pb system took place at 525 ± 7 Ma (Pampean orogeny) and at ca. 430-440 Ma (Famatinian orogeny) and it is concluded that the Western Sierras Pampeanas basement was joined to Gondwana during both events. Highly unradiogenic 87Sr/86Sr values in calcites (0.70275-0.70305) provide a close estimate for the initial Sr isotope composition of the carbonatite magma. Sm-Nd data yield εNd570 values of +3.3 to +4.8. The complex was probably formed during early opening of the Clymene Ocean from depleted mantle with a component from Meso/Neo-proterozoic lower continental crust.
dc.identifier.issn0301-9268
dc.identifier.urihttp://hdl.handle.net/1885/36327
dc.publisherElsevier
dc.sourcePrecambrian Research
dc.subjectKeywords: calcite; carbonatite; deformation; Gondwana; Grenvillian orogeny; igneous rock; isotope; lithology; mantle; Proterozoic; syenite; uranium-lead dating; zircon; Argentina; Sierras Pampeanas; South America DARCs; Gondwana; Rodinia; Syenite; U-Pb SHRIMP zircon dating
dc.titleA deformed alkaline igneous rock-carbonatite complex from the Western Sierras Pampeanas, Argentina: Evidence for late Neoproterozoic opening of the Clymene Ocean?
dc.typeJournal article
local.bibliographicCitation.lastpage220
local.bibliographicCitation.startpage205
local.contributor.affiliationCasquet, Cesar, Universidad Complutense de Madrid
local.contributor.affiliationPankhurst, Robert J, British Geological Survey
local.contributor.affiliationGalindo, Carmen, Universidad Complutense de Madrid
local.contributor.affiliationRapela, Carlos W, Universidad Nacional de La Plata
local.contributor.affiliationFanning, Christopher, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationBaldo, Edgardo, Universidad Nacional de Cordoba
local.contributor.affiliationDahlquist, Juan A., CRILAR-CONICET
local.contributor.affiliationGonzalez-Casado, Jose M, Universidad Autonoma de Madrid
local.contributor.affiliationColombo, Fernando, Universidad Nacional de Cordoba
local.contributor.authoremailu4029993@anu.edu.au
local.contributor.authoruidFanning, Christopher, u4029993
local.description.embargo2037-12-31
local.description.notesImported from ARIES
local.identifier.absfor040304 - Igneous and Metamorphic Petrology
local.identifier.absfor040313 - Tectonics
local.identifier.absfor040203 - Isotope Geochemistry
local.identifier.ariespublicationu4027924xPUB135
local.identifier.citationvolume165
local.identifier.doi10.1016/j.precamres.2008.06.011
local.identifier.scopusID2-s2.0-51449119851
local.identifier.thomsonID000259794500006
local.identifier.uidSubmittedByu4027924
local.type.statusPublished Version

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