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	Provedor de dados Anais da ABC (AABC) (2) Autor MOTOKI,AKIHISA (2) MOTOKI,KENJI F. (2) SICHEL,SUSANNA E. (2) MELO,DEAN P. (1) VARGAS,THAIS (1) Palavra-chave Alkaline syenite (1) Continental crust assimilation (1) Fractional crystallization (1) Mantle exhumation (1) Nepheline syenite (1) Rare earth elements (1) Saint Peter and Saint Paul peridotite ridge (1) Satellite gravimetry (1) Serpentinization (1) Submarine geomorphology (1) Trace elements (1) Mais... Tipo do documento Info:eu-repo/semantics/article (2) Ano 2015 (1) 2014 (1) País Brazil (2) Idioma Inglês (2)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 2 Primeira ... 1 ... Última Geochemical behaviour of trace elements during fractional crystallization and crustal assimilation of the felsic alkaline magmas of the state of Rio de Janeiro, Brazil Anais da ABC (AABC) MOTOKI,AKIHISA; SICHEL,SUSANNA E.; VARGAS,THAIS; MELO,DEAN P.; MOTOKI,KENJI F.. ABSTRACT This paper presents geochemical behaviour of trace elements of the felsic alkaline rocks of the state of Rio de Janeiro, Brazil, with special attention of fractional crystallization and continental crust assimilation. Fractionation of leucite and K-feldspar increases Rb/K and decreases K2O/(K2O+Na2O). Primitive nepheline syenite magmas have low Zr/TiO2, Sr, and Ba. On the Nb/Y vs. Zr/TiO2 diagram, these rocks are projected on the field of alkaline basalt, basanite, and nephelinite, instead of phonolite. Well-fractionated peralkaline nepheline syenite has high Zr/TiO2 but there are no zircon. The diagrams of silica saturation index (SSI) distinguish the trends originated form fractional crystallization and crustal assimilation. In the field of... Tipo: Info:eu-repo/semantics/article Palavras-chave: Nepheline syenite; Alkaline syenite; Trace elements; Rare earth elements; Fractional crystallization; Continental crust assimilation. Ano: 2015 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652015000501959 Gravimetric structure for the abyssal mantle massif of Saint Peter and Saint Paul peridotite ridge, Equatorial Atlantic Ocean, and its relation to active uplift Anais da ABC (AABC) MOTOKI,KENJI F.; MOTOKI,AKIHISA; SICHEL,SUSANNA E.. This paper presents gravimetric and morphologic analyses based on the satellite-derived data set of EGM2008 and TOPEX for the area of the oceanic mantle massif of the Saint Peter and Saint Paul peridotite ridge, Equatorial Atlantic Ocean. The free-air anomaly indicates that the present plate boundary is not situated along the longitudinal graben which cuts peridotite ridge, but about 20 km to the north of it. The high Bouguer anomaly of the peridotite ridge suggests that it is constituted mainly by unserpentinised ultramafic rocks. The absence of isostatic compensation and low-degree serpentinisation of the ultramafic rocks indicate that the peridotite ridge is sustained mainly by active tectonic uplift. The unparallel relation between the transform fault... Tipo: Info:eu-repo/semantics/article Palavras-chave: Mantle exhumation; Saint Peter and Saint Paul peridotite ridge; Satellite gravimetry; Serpentinization; Submarine geomorphology. Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652014000200571 Registros recuperados: 2 Primeira ... 1 ... Última

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