DACITIC VOLCANISM IN THE COURSE OF THE RIO DAS VELHAS (2800-2690 Ma) OROGENY: A BRAZILIAN ARCHEAN ANALOGUE (TTD) TO THE MODERN ADAKITES

DACITIC VOLCANISM IN THE COURSE OF THE RIO DAS VELHAS (2800-2690 Ma) OROGENY: A BRAZILIAN ARCHEAN ANALOGUE (TTD) TO THE MODERN ADAKITES

dc.contributoren-US
dc.contributorpt-BR
dc.creatorSILVA, LUIZ CARLOS DA
dc.creatorNOCE, CARLOS MAURÍCIO
dc.creatorLOBATO, LYDIA MARIA
dc.date2017-03-29
dc.date.accessioned2022-12-15T20:36:41Z
dc.date.available2022-12-15T20:36:41Z
dc.identifierhttps://ppegeo.igc.usp.br/index.php/rbg/article/view/10650
dc.identifier.urihttps://repositorioslatinoamericanos.uchile.cl/handle/2250/5361625
dc.descriptionThe evolution of the Rip das Velhas Greenstone Belt followed two main episodes of crustal addition. An initial phase of ocean- floor spreading is associated with tholeiitic to komatiitic magmatism. This early accreted, short-lived oceanic crust underwent rapid subduction, giving rise to widespread arc-related, felsic calc-alkaline volcanism, triggered by the direct melting of the oceanic slab. The felsic rocks comprise lavas and pyroclastic facies, extruded at ca. 2775 Ma and rapidly dispersed through syn- and post-eruptive submarine resedimentation processes. The sequence is coeval with a series of granitoids intrusive into the belt margins, characterizing a tonalite-trondhjemite-dacite (TTD) magmatism. The LILE depleted, Na-rich, chemical signature shown by the volcanic rocks fits well with a genetic model which incorporates aspects of the evolution of adakites in the modern Circum-Pacific arcs, and also the ancient FI dacites from the Barberton Greenstone Belt. Keywords: Rio das Velhas Greenstone Belt, evolution, Archean felsic volcanism, adakites, TTD associationen-US
dc.descriptionThe evolution of the Rip das Velhas Greenstone Belt followed two main episodes of crustal addition. An initial phase of ocean- floor spreading is associated with tholeiitic to komatiitic magmatism. This early accreted, short-lived oceanic crust underwent rapid subduction, giving rise to widespread arc-related, felsic calc-alkaline volcanism, triggered by the direct melting of the oceanic slab. The felsic rocks comprise lavas and pyroclastic facies, extruded at ca. 2775 Ma and rapidly dispersed through syn- and post-eruptive submarine resedimentation processes. The sequence is coeval with a series of granitoids intrusive into the belt margins, characterizing a tonalite-trondhjemite-dacite (TTD) magmatism. The LILE depleted, Na-rich, chemical signature shown by the volcanic rocks fits well with a genetic model which incorporates aspects of the evolution of adakites in the modern Circum-Pacific arcs, and also the ancient FI dacites from the Barberton Greenstone Belt. Keywords: Rio das Velhas Greenstone Belt, evolution, Archean felsic volcanism, adakites, TTD associationpt-BR
dc.formatapplication/pdf
dc.languageeng
dc.publisherSociedade Brasileira de Geologiapt-BR
dc.relationhttps://ppegeo.igc.usp.br/index.php/rbg/article/view/10650/10158
dc.rightsDireitos autorais 2017 Revista Brasileira de Geociênciaspt-BR
dc.sourceRevista Brasileira de Geociências; v. 30, n. 3 (2000); 384-387en-US
dc.sourceRevista Brasileira de Geociências; v. 30, n. 3 (2000); 384-387es-ES
dc.sourceRevista Brasileira de Geociências; v. 30, n. 3 (2000); 384-387pt-BR
dc.source0375-7536
dc.subjectRio das Velhas Greenstone Belt; Evolution; Archean felsic volcanis; Adakites; TTD association.en-US
dc.subjectRio das Velhas Greenstone Belt; Evolution; Archean felsic volcanis; Adakites; TTD association.pt-BR
dc.titleDACITIC VOLCANISM IN THE COURSE OF THE RIO DAS VELHAS (2800-2690 Ma) OROGENY: A BRAZILIAN ARCHEAN ANALOGUE (TTD) TO THE MODERN ADAKITESen-US
dc.titleDACITIC VOLCANISM IN THE COURSE OF THE RIO DAS VELHAS (2800-2690 Ma) OROGENY: A BRAZILIAN ARCHEAN ANALOGUE (TTD) TO THE MODERN ADAKITESpt-BR
dc.typeinfo:eu-repo/semantics/article
dc.typeinfo:eu-repo/semantics/publishedVersion
dc.typept-BR


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