Structural breakdown and thermal behavior of selected borosilicate minerals

The specific objective of this thesis was the definition of thermal behavior, breakdown mechanisms and breakdown products of selected borosilicates, specifically tourmalines and axinites, which are the most and the less investigated borosilicate phases, respectively, occurring in geological settings. The general objective was to assess the role of borosilicates in the dehydration embrittlement process along the downgoing slab, leading to the definition of their stability fields and to the quantitative evaluation of B-enriched fluids released during possible oxidation-deprotonation processes and structural breakdown of such mineral phases.