Topic of the talk
Nanorocks are minute objects of great importance for the characterization of crustal differentiation, a process that, over the last 4 billion years, has been shaping the Earth´s crust through endless cycles of re-melting and melt migration. The nanorocks trap and preserve exactly these deep melts, providing compositional data of pivotal importance for unraveling the evolution of our planet.
In recent years high-resolution microscale studies on nanorocks and fluid inclusions, in combination with classic petrology and phase equilibrium modelling, has caused the research on deep melting during orogenesis to take gigantic leaps forward. Nanorocks can survive the long journey of the host rock to the surface and remain unchanged because sheltered in refractory minerals such as garnet and few others sturdy hosts. By finding and studying nanorocks, we are now able to directly measure natural melts generated from melting of virtually any protolith throughout the entire geological timescale and over a wide PT range. The trace elements in the melt clarifies which melting reactions took place, and this helps to correlate melt presence with P-T-t evolution of the rocks. The volatile content (CO2, H2O, Cl, F) of the melt shows instead which fluid (acqueous, carbon-rich or saline) and how much of it was present at depth during melting. With these novel data we can calculate more precisely the melt viscosity at depth, as well as refine the estimates of the continental crust contribution to the global volatile cycle over geological times.
This is also a fertile ground for unexpected discoveries such as new mineral phases, rare feldspar polymorphs, crustal carbonatites and preserved metasomatizing melts in eclogites - just a few example of the new research avenues opening up as we target more and more case studies of melt inclusions in metamorphic rocks.

Short bio
Silvio Ferrero earned his Phd in 2010 with Bernardo Cesare (Padova) and later worked as a “micropetrologist of inclusions” on diverse aspects of crustal evolution at UniPotsdam, as Alexander vonHumboldt fellow and DFG fundee. Since arriving in Cagliari in 2022, he targets microstructures in plutonic rocks to clarify post-collisional magmatism in the Variscan chain.