The contribution of synchrotron X-ray computed microtomography to understanding volcanic processes

Abstract

A series of computed microtomography experiments are reported which were performed by using a third-generation synchrotron radiation source on volcanic rocks from various active hazardous volcanoes in Italy and other volcanic areas in the world. The applied technique allowed the internal structure of the investigated material to be accurately imaged at the micrometre scale and threedimensional views of the investigated samples to be produced as well as threedimensional quantitative measurements of textural features. The geometry of the vesicle (gas-filled void) network in volcanic products of both basaltic and trachytic compositions were particularly focused on, as vesicle textures are directly linked to the dynamics of volcano degassing. This investigation provided novel insights into modes of gas exsolution, transport and loss in magmas that were not recognized in previous studies using solely conventional twodimensional imaging techniques. The results of this study are important to understanding the behaviour of volcanoes and can be combined with other geosciences disciplines to forecast their future activity.

Advances in the rheology of natural multiphase silicate melts: Import for magma transport and lava flow emplacement

“…A further advancement is the 4D characteriza− tion of the sub liquidus evolution of natural melts is represented by experiments within synchrotron facil− ities which allow real time monitoring of the textural evolution of samples of volcanological interest during crystallization and/or degassing [e.g. Ohtani et al, 2005;Pistone et al, 2015;Pleše et al, 2018;Polacci et al, 2018;Polacci et al, 2010;Song et al, 2001]. These techniques are starting to be coupled with devices for rheometry, which may in the future allow for in situ es− timates of both the crystallization kinetics and the rhe− ological response of evolving natural systems [Coats et al, 2017;Dobson et al, 2015;Dobson et al, 2016;Raterron and Merkel, 2009].…”

Development of an X-ray imaging system to prevent scintillator degradation for white synchrotron radiation

“…Attenuation contrast works well for distinguishing between crystals and air for porous samples. However, because of the chemical similarity between the macrocrystal and the matrix there is very little difference in attenuation, which means that phase contrast is highly valuable (Polacci et al, 2010). The development of this imaging system allows for new dynamic experiments to be designed that test long-held assumptions regarding the origin and evolution of these and other magmas.…”

A compact and flexible induction furnace for in situ X-ray microradiograhy and computed microtomography at Elettra: design, characterization and first tests

“…Furthermore, such a setup is ideal for the sCMOS detector, which has the capability to acquire and read out individual projections at rates that are orders of magnitude faster than the traditional CCD cameras. For both configurations, experiments were performed in propagation-based phase-contrast mode (Cloetens et al, 1997;Polacci et al, 2010).…”