An??lise de correspond?ancias de litogeoqu?-mica de vulcanismos cenozoicos na por?§?￡o setentrional da Prov?-ncia Borborema, Brasil

摘要

The lithogeochemical correlation among samples generally uses pre-defined graphs in the literature or bivariate analysis??for each of the elements analyzed. Applying a multivariate analysis to the geochemical data of a set of samples, which are??naturally multivariate, allows to deal with these data in a reduced dimensional space, thus understanding the behavioral??processes of individuals. Correspondence Analysis (CA) also permits comparing individuals (rows) and quantitative or??qualitative variables (columns) of a set of data in the same workspace and in a symmetrical way. In this paper, the CA of a??set of geochemical analyzes of Cenozoic volcanic rocks of the Borborema Provincea??s Northern portion correlated a newly??discovered volcanic occurrence at Fortaleza to Fernando de Noronhaa??s alkaline volcanism, distinguishing itself from the??volcanism of Macau, mainly due to its relative depletion in Rare Earth Elements. The method also allowed to distinguish??some geochemical similarities between rocks from Fortaleza and Fernando de Noronha, such as higher values of Na 2 O,??K 2 O, Al 2 O 3 , TiO 2 , P 2 O 5 and CaO 2 , and smaller of SiO 2 e MgO relatively to those of Macau Volcanism. Trace elements like??Rb, Nb, Th and Ga are correlated, and their values increase or decline together on each volcanism, while Sr and Ba have??an inverse behavior of Cr and Ni.