Mineral chemistry and geothermobarometry of Neoproterozoic rocks from northeast Dom Feliciano Belt, southernmost Brazil

Abstract The northeast of the Dom Feliciano Belt comprises three post-transcurrent granitic suites having high-K calc-alkaline and alkaline affinity intruded in a tonalitic gneissic basement. In order to obtain data regarding the pressure and temperature conditions of these rocks, geothermobarometric methods based on mineral chemistry and whole-rock geochemistry were applied. The mineral chemistry of the amphiboles of gneiss registered two sets of pressure conditions that were interpreted as having an igneous core, with temperatures, pressures, and depths, respectively, from 710 to 760 °C, 3.4–3.9 kbar and 12–14 km and a metamorphic rim of 690–760 °C, 4.8–7.7 kbar and 18–28 km. Amphiboles from granites recorded temperatures from 659 to 759 and pressures from 3.2 to 5.0 kbar, with depths from 11 to 18 km. The temperatures obtained from the Zr content in titanite from granites registered a range from 607 to 881 °C, which were interpreted, as magmatic (700–881 °C) and post-magmatic origin (