Geological evolution of the basement rocks in the east-central part of the Rondonia Tin Province, SW Amazonian craton, Brazil: U-Pb and Sm-Nd isotopic constraints

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dc.contributor.authorPayolla, B. L.
dc.contributor.authorBettencourt, J. S.
dc.contributor.authorKozuchi, M.
dc.contributor.authorLeite, W. B.
dc.contributor.authorFetter, A. H.
dc.contributor.authorVan Schmus, W. R.
dc.contributor.institutionCtr Eletr N Brasil SIA
dc.contributor.institutionUniversidade de São Paulo (USP)
dc.contributor.institutionUniversity of Kansas (KU)
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2014-05-20T15:25:37Z
dc.date.available2014-05-20T15:25:37Z
dc.date.issued2002-12-20
dc.description.abstractOn the basis of geologic, petrologic, and U-Pb geochronologic data the basement rocks in the east-central part of the Rondonia Tin Province (RTP, southwestern Amazonian craton) are grouped into five lithologic associations: (1) tonalitic gneiss (1.75 Ga); (2) enderbitic granulite (1.73 Ga); (3) paragneiss; (4) granitic and charnockitic augen gneisses (1.57-1.53 Ga); and (5) fine-grained granitic gneiss and charnockitic granulite (1.43-1.42 Ga). The first three are related to development of the Paleoproterozoic Rio Negro-Juruena Province and represent the oldest crust in the region. The tonalitic gneisses and enderbitic granulites show calc-alkaline affinities and Nd isotopic compositions (initial epsilon(Nd) = +0-1 to -1.5; T-DM of 2.2-2.1 Ga) that suggest a continental arc margin setting for the original magmas. The paragneisses yield T-DM values of 2.2-2.1 Ga suggesting that source material was primarily derived from the Ventuari-Tapajos and Rio Negro-Juruena crusts, but detrital zircon ages and an intrusive granitoid bracket deposition between 1.67 and 1.57 Ga. The granitic and charnockitic augen gneisses show predominantly A-type and within-plate granite affinities, but also some volcanic arc granite characteristics. The initial epsilon(Nd) values (+0.6 to +2.0) indicate mixing of magmas derived from depleted mantle and older crustal sources. These rocks are correlated to the 1.60-1.53 Ga Serra da Providencia intrusive suite that reflects inboard magmatism coeval with the Cachoeirinha orogen located to the southeast. The fine-grained granitic gneiss and charnockitic granulites represent the first record of widespread magmatism at 1.43-1.42 Ga in northern Rondonia. Their geochemical signatures and the slightly positive initial epsilon(Nd) values (+0.7 to +1.2) are very similar to those of the most evolved granites of the calc-alkaline Santa Helena batholith farther southeast. U-Pb monazite and Sm-Nd whole-rock-garnet ages demonstrate that a high-grade tectonometa-morphic episode occurred in this region at 1.33-1.30 Ga. This episode attained upper-amphibolite conditions and is interpreted as the peak of the Rondonian-San Ignacio orogeny. The U-Pb and Sm-Nd data presented here and data published on rapakivi granites elsewhere indicate that the east-central part of the RTP is a poly-orogenic region characterized by successive episodes of magmatism, metamorphism, and deformation between 1.75 and 0.97 Ga. (C) 2002 Elsevier B.V. B.V. All rights reserved.en
dc.description.affiliationCtr Eletr N Brasil SIA, BR-70856120 Brasilia, DF, Brazil
dc.description.affiliationUniv São Paulo, Inst Geosci, BR-05422970 São Paulo, Brazil
dc.description.affiliationUniv Kansas, Dept Geol, Lawrence, KS 66045 USA
dc.description.affiliationUniv Estadual Paulista, Inst Geociencias & Ciências Exatas, BR-13506900 Rio Claro, Brazil
dc.description.affiliationUnespUniv Estadual Paulista, Inst Geociencias & Ciências Exatas, BR-13506900 Rio Claro, Brazil
dc.format.extent141-169
dc.identifierhttp://dx.doi.org/10.1016/S0301-9268(02)00121-3
dc.identifier.citationPrecambrian Research. Amsterdam: Elsevier B.V., v. 119, n. 1-4, p. 141-169, 2002.
dc.identifier.doi10.1016/S0301-9268(02)00121-3
dc.identifier.issn0301-9268
dc.identifier.urihttp://hdl.handle.net/11449/35990
dc.identifier.wosWOS:000179936700007
dc.language.isoeng
dc.publisherElsevier B.V.
dc.relation.ispartofPrecambrian Research
dc.relation.ispartofjcr3.907
dc.relation.ispartofsjr2,769
dc.rights.accessRightsAcesso restrito
dc.sourceWeb of Science
dc.subjectAmazonian cratonpt
dc.subjectRondonia Tin Provincept
dc.subjectMesoproterozoicpt
dc.subjectU-Pb geochronologypt
dc.subjectSm-Nd isotopespt
dc.titleGeological evolution of the basement rocks in the east-central part of the Rondonia Tin Province, SW Amazonian craton, Brazil: U-Pb and Sm-Nd isotopic constraintsen
dc.typeArtigo
dcterms.licensehttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy
dcterms.rightsHolderElsevier B.V.

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