Effect of pressure on silicate glasses and melts structure: experimental investigation on a primitive alkaline basalt from the Campi Flegrei Volcanic District (South Italy)
Investigating the structure of silicate melts representative of natural magmas improves our understanding about the rheology of ascending magmas and their behavior once erupted on the surface. In this project, I propose to investigate the effect of pressure on the internal network structure of an alkaline basalt from the Campi Flegrei Volcanic District by using the multi-angle energy dispersive synchrotron X-ray diffraction (EDXD) technique combined with micro-Raman spectroscopy. By the combination of both techniques, I aim to obtain unique and novel information on the arrangement of atoms forming the amorphous structure typical of natural magmas that, in turn, has dramatic effects on the viscosity and explosivity of volcanic eruptions. To achieve the goals of this project, I will reproduce pressure and temperature conditions at which natural magmas might form and undergo before being emplaced at crustal levels within magma chambers. Experimental simulations will be performed using natural lavas like APR16, a K-basalt lithic lava fragment found in the deposits of the Solchiaro tuff in Procida island (Campi Flegrei Volcanic District, south Italy). The application of both in situ X-ray diffraction methods on the synthetic magma at high pressure and temperature followed by spectroscopic Raman techniques at ambient conditions will allow me to model the structure of a melt at the atomic level during decompression and cooling. I expect to obtain important data such as interatomic distances and degree of polymerization that can be used to model the volcanic style of active and quiescent volcanoes knowing the present-day eruptive style and the chemical composition of natural erupted lithic products.