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dc.contributor.authorRocha-Júnior, Eduardo R.V.-
dc.contributor.authorMarques, Leila S.-
dc.contributor.authorBabinski, Marly-
dc.contributor.authorNardy, Antônio J.R.-
dc.contributor.authorFigueiredo, Ana M.G.-
dc.contributor.authorMachado, Fábio B.-
dc.identifier.citationJournal of South American Earth Sciences, v. 46, p. 9-25.-
dc.description.abstractThere has been little research on geochemistry and isotopic compositions in tholeiites of the Northern region from the Paraná Continental Flood Basalts (PCFB), one of the largest continental provinces of the world. In order to examine the mantle sources involved in the high-Ti (Pitanga and Paranapanema) basalt genesis, we studied Sr, Nd, and Pb isotopic systematics, and major, minor and incompatible trace element abundances. The REE patterns of the investigated samples (Pitanga and Paranapanema magma type) are similar (parallel to) to those of Island Arc Basalts' REE patterns. The high-Ti basalts investigated in this study have initial (133Ma) 87Sr/86Sr ratios of 0.70538-0.70642, 143Nd/144Nd of 0.51233-0.51218, 206Pb/204Pb of 17.74-18.25, 207Pb/204Pb of 15.51-15.57, and 208Pb/204Pb of 38.18-38.45. These isotopic compositions do not display any correlation with Nb/Th, Nb/La or P2O5/K2O ratios, which also reflect that these rocks were not significantly affected by low-pressure crustal contamination. The incompatible trace element ratios and Sr-Nd-Pb isotopic compositions of the PCFB tholeiites are different to those found in Tristan da Cunha ocean island rocks, showing that this plume did not play a substantial role in the PCFB genesis. This interpretation is corroborated by previously published osmium isotopic data (initial γOs values range from+1.0 to+2.0 for high-Ti basalts), which also preclude basalt generation by melting of ancient subcontinental lithospheric mantle. The geochemical composition of the northern PCFB may be explained through the involvement of fluids and/or small volume melts related to metasomatic processes. In this context, we propose that the source of these magmas is a mixture of sublithospheric peridotite veined and/or interlayered with mafic components (e.g., pyroxenites or eclogites). The sublithospheric mantle (dominating the osmium isotopic compositions) was very probably enriched by fluids and/or magmas related to the Neoproterozoic subduction processes. This sublithospheric mantle region may have been frozen and coupled to the base of the Parana basin lithospheric plate above which the Paleozoic subsidence and subsequent Early Cretaceous magmatism occurred. © 2013 Elsevier Ltd.en
dc.subjectHigh-TiO2 basalts-
dc.subjectMantle plume-
dc.subjectMantle sources-
dc.subjectParaná Continental Flood Basalts-
dc.subjectSr-Nd-Pb isotopic systematics-
dc.subjectflood basalt-
dc.subjectigneous geochemistry-
dc.subjectisotopic composition-
dc.subjectlead isotope-
dc.subjectmantle plume-
dc.subjectmantle source-
dc.subjectneodymium isotope-
dc.subjectrare earth element-
dc.subjectstrontium isotope-
dc.subjecttrace element-
dc.subjectParana [Brazil]-
dc.subjectEugenia uniflora-
dc.titleSr-Nd-Pb isotopic constraints on the nature of the mantle sources involved in the genesis of the high-Ti tholeiites from northern Paraná Continental Flood Basalts (Brazil)en
dc.contributor.institutionUniversidade de São Paulo (USP)-
dc.contributor.institutionUniversidade Federal do Rio Grande do Sul (UFRGS)-
dc.contributor.institutionUniversidade Estadual Paulista (UNESP)-
dc.contributor.institutionInstituto de Pesquisas Energéticas e Nucleares (IPEN)-
dc.contributor.institutionUniversidade Federal de São Paulo (UNIFESP)-
dc.description.affiliationInstituto de Astronomia, Geofísica e Ciências Atmosféricas Universidade de São Paulo, São Paulo, SP 05508-090-
dc.description.affiliationInstituto de Geociências Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501-970-
dc.description.affiliationInstituto de Geociências Universidade de São Paulo, São Paulo, SP 05422-970-
dc.description.affiliationInstituto de Geociências e Ciências Exatas Universidade Estadual Paulista, Rio Claro, SP-
dc.description.affiliationInstituto de Pesquisas Energéticas e Nucleares, Av. Prof. Lineu Prestes 2242, São Paulo, SP 05508-000-
dc.description.affiliationDepartamento de Ciências Exatas e da Terra Universidade Federal de São Paulo, Diadema, SP-
dc.description.affiliationUnespInstituto de Geociências e Ciências Exatas Universidade Estadual Paulista, Rio Claro, SP-
dc.rights.accessRightsAcesso restrito-
dc.relation.ispartofJournal of South American Earth Sciences-
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