GEOCHEMISTRY OF THE SERRA DO MAR GRANITOID MAGMATISM AND TECTONIC IMPLICATIONS, SOUTHERN BRAZIL

PEDRO FRANCISCO TEIXEIRA KAUL, UMBERTO GIUSEPPE CORDANI

Resumo


The Neoproterozoic (580 ± 20 Ma) alkaline granitoid magmatism produced two rock associations in the Serra do Mar region, Southern Brazil. The first one (70-76% SiO2) is metaluminous to weakly peraluminous, HFSE depleted relative to LILE, and includes the larger massifs mainly. The second one (62-76% SiO2) comprises metaluminous as well as peralkaline rock-types and is enriched in HFSE relative to LILE. The granitoid massifs were emplaced within transtensional fault zones generated during the final stages of the agglutination process that led to the formation of the Gondwana supercontinent. As a whole, the Serra do Mar granitoid magmatism represents a transition from late orogenic calc-alkaline monzonitic to anorogenic alkaline (A-type) magmatism.

Palavras-chave


Geochemistry; Granitoid magmatism; Magmatic evolution; Tectonic regime; Serra do Mar.

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