Petrology, Geochemistry and Economic Aspects of the Alkaline Dyke in Anta Gorda Region, Doutor Ulysses, Paraná, Brazil

Abstract

The rock types of the alkaline dyke from Anta Gorda region, in the township of Doutor Ulysses (State of Paraná), encompass three lithological groups that have been individualized for their distinct textural, structural, mineralogical and/or geochemical characteristics: phonolites s.s ., amygdaloidal phonolites and trachyphonolites. These are rocks with magmatic derivation, in which the most important differentiation processes interpreted were immiscibility and fractional crystallization from the ultrabasic mantellic source with primary magma. Fenite epidotes were also classified in the study area, probably product of fenitization of the granitic wall rock. Due to the geographical proximity, some similarities between the phonolites and the rocks from the Barra do Teixeira alkaline plug or the Banhad ã o Alkaline Complex were expected. However, the results of the petrographic and geochemical analysis point to major resemblance between the phonolites and the lithotypes of the Mato Preto Alkaline Complex. The studied rocks contain concentrations of economic interest of important chemicals elements, mainly Rare Earth Elements—REE, trace elements and mineral substances, such as zeolites and fluorites.