Rhyacian A-type Tholeiitic Granites In Southern Brazil: Geochemistry, U-pb Zircon Ages And Nd Model Ages

dc.creatorMesquita
dc.creatorMaria Jose; Bitencourt
dc.creatorMaria de Fatima; Nardi
dc.creatorLauro Stoll; Picanco
dc.creatorJefferson; Chemale
dc.creatorFarid
dc.creatorJr.; Pimenta
dc.creatorVanessa de Almeida
dc.date2017
dc.dateabr
dc.date2017-11-13T11:33:23Z
dc.date2017-11-13T11:33:23Z
dc.date.accessioned2018-03-29T05:47:51Z
dc.date.available2018-03-29T05:47:51Z
dc.identifierLithos. Elsevier Science Bv, v. 277, p. 92 - 108, 2017.
dc.identifier0024-4937
dc.identifier1872-6143
dc.identifierWOS:000399514500006
dc.identifier10.1016/j.lithos.2016.09.005
dc.identifierhttp://www-sciencedirect-com.ez88.periodicos.capes.gov.br/science/article/pii/S0024493716302766?via%3Dihub
dc.identifierhttp://repositorio.unicamp.br/jspui/handle/REPOSIP/326258
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1363264
dc.descriptionConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.descriptionIn the southern South American platform, 2.5 to 2.0 Ga terranes, probably related to the Atlantica supercontinent, occur mainly as minor reworked inliers within Neoproterozoic, Brasiliano/Pan-African orogenic belts, as the Ribeira Belt in southern Brazil. The dispersion of such fragments has generated uncertainties about their geotectonic reconstruction, and their study has been supported mainly by elemental and isotope geochemistry. The southern Ribeira Belt lies between the Paranapanema and Luiz Alves cratons and contains reworked Neoarquean and Paleoproterozoic terranes which outcrop as basement nuclei in supracrustal sequences, as the Setuva Complex. The Agua Comprida Suite, situated in the northern part of the Setuva Complex, consists of Amphibole-Biotite Syenogranite (ABS), Porphyritic Biotite Syenogranite (PBS), and Equigranular Biotite Syenogranite (EBS). All granites are foliated and intensively deformed. The oldest foliation (S-n) is marked by augen feldspars set in a recrystallized matrix, followed by a crenulation cleavage (Sn + 1) which evolves to discrete shear zones. ABS is a metaluminous, reduced A-type granite with FeOt / (FeOt + MgO) > 0.9, with high HFSE and REE contents, corresponding to magmas related to continental medium to high-K tholeiitic series. PBS and specially EBS are highly differentiated, metaluminous to peraluminous (EBS), oxidized granites. The increase of Al2O3 and Rb, and decrease of HFS and RE elements relative to ABS indicate their evolution from tholeiitic magmas. The Agua Comprida Suite granites are cogenetic rocks evolved from a within-plate mantle source, marked by high Nb, Ta, and Y. The influence of previously metasomatised mantle sources is evidenced by negative Nb, Ti, and P anomalies. The age of ABS is 2187 +/- 26 Ma, and that of PBS is between 2180 +/- 13 to 2186 +/- 22 Ma. The Nd model age of 2.4 Ga, and epsilon Nd-(2.18 Ga) between -0.23 and -0.27 support the interpretation of ABS being formed from juvenile material with a minor crustal component. The deviation of epsilon Nd-(2.18 Ga) for PBS and EBS (-0.69 to -2.65), plus the higher Nd model ages (2.4 to 2.5 Ga) suggest crustal contamination. A post-collisional environment for the interaction of the mafic tholeiitic and felsic crustal magmas is suggested for the formation of the Agua Comprida Suite, based mainly on geochemical features of these magmas. Post-collisional environments are still not described in the Rhyacian orogenies of southern Brazil, and this proposition may be an important contribution for the study of the final period of amalgamation of the Paleoproterozoic supercontinent in southern South America. (C) 2016 Elsevier B.V. All rights reserved.
dc.description277
dc.description92
dc.description108
dc.descriptionBrazilian Research Council (CNPq) [150664/2005-2]
dc.descriptionFC
dc.descriptionConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.description8th Hutton Symposium on Granites and Related Rocks
dc.descriptionSEP 20-25, 2015
dc.descriptionFlorianopolis, BRAZIL
dc.description
dc.languageEnglish
dc.publisherElsevier Science BV
dc.publisherAmsterdam
dc.relationLithos
dc.rightsfechado
dc.sourceWOS
dc.subjectHigh-k Tholeiitic Granites
dc.subjectRhyacian Granitic Magmatism
dc.subjectA-type Tholeiitic Granites
dc.subjectA(2)-type Granites
dc.subjectPost-collisional Magmatism
dc.titleRhyacian A-type Tholeiitic Granites In Southern Brazil: Geochemistry, U-pb Zircon Ages And Nd Model Ages
dc.typeActas de congresos


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