Boron, Arsenic and Antimony distribution in some basement rocks of the Northern Apennines

In the present work 53 samples of metamorphic rocks have been analyzed for boron, arsenic and antimony, in order to obtain a geochemical characterization of the Tuscan Paleozoic Basement. A regional background of 70 ppm, 4 and ≤ 0.2 ppm respectively for boron, arsenic and antimony, is suggested by the data. The partial boron mobilization determined by Alpine metamorphic events on the original sedimentary rocks seems to be more important for the metapelitic lithotype (B median value ~ 58 ppm), than for meta-psammitic ones (70 ppm). In fact the meta-psammites are characterized by the presence of detrital tourmaline, which kept the original boron content. A tentative geochemical discrimination based on the age of the Formations suggests a regional depletion for the pre-Sudetic formations with respect of the Permo-Carboniferous ones. -from Authors