Flow-by-flow chemical stratigraphy and evolution of thirteen Serra Geral Group basalt flows from Vista Alegre, southernmost Brazil

Anais da Academia Brasileira de Ciências

Viter M Pinto²  Léo A Hartmann¹ 

[1] ,Universidade Federal de Roraima Instituto de Geociências Boa Vista RR ,Brasil

关键词: Geochemical correlation;    basalt;    stratigraphy;    Serra Geral Group;    Vista Alegre;    Correlação geoquímica;    basalto;    estratigrafia;    Grupo Serra Geral;    Vista Alegre;   

DOI  :  10.1590/S0001-37652011000200006

来源: SciELO

【 摘 要 】

The geochemical characterization of thirteen Serra Geral Group flows in the Vista Alegre region (RS-SC), southern Brazil, displays the homogeneous basaltic composition near 50 wt.% SiO2. Each of the five basal flows (Pitanga-type, high-Ti/Y ~600, TiO2 > 3 wt.%) and eight upper flows (Paranapanema-type, medium Ti/Y ~400, TiO2 > 2 wt.%) can be identified from their chemical composition; sets of flows have parallel variation in chemical composition. The flow-by-flowcorrelation in four sections shows the horizontal position of the flows in three profiles and an approximately 200-m downdrop of the Itapiranga block with respect to the Frederico Westphalen block. The world-class amethyst geode mineralization and the systematic presence of native copper in the basalts make the correlation of great geological and economic significance.

【 授权许可】

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