Identification of source areas and crystallization conditions of granitic magmas based on mineral and rock geochemistry

Abstract

The project has as main object of study occurrences of "classical" granite rocks from the geology of the SE of Brazil (Itu and Socorro batoliths; Pedra Branca Syenite, Atibaia Granite and Piracaia Monzodiorite), whose basic geological, petrographic and geochronological characteristics were established in previous studies. Thus, they are prone to in-depth studies of magma generation processes, identifying source areas in the crust and mantle, and to the identification of evolution processes in magmatic chambers (fractional crystallization, magma mixing, contamination) using as a main tool elemental and isotopic geochemistry (Sr-Nd-Hf). The crystallization conditions of the rocks (temperature, pressure, oxygen fugacity) will be investigated with modern in situ geochemical tools, involving main minerals (feldspars, amphiboles) and accessories (apatite, zircon, titanite). In parallel, in view of the importance of understanding the role of granites throughout the neoproterozoic regional tectonic cycle, the project opens a specific line of research on early granitic magmatism, which is registered as expressive bodies of orthognaisses, so far not systematically studied. (AU)