Among the various laboratories of the Pisa Section of the National Institute of Geophysics and Volcanology (INGV) is the recently renovated petrology and volcanology laboratory located in the new headquarters of the Sesta Porta. We asked the manager Alessio Di Roberto to tell us in detail about the activities that take place inside.
What studies are conducted in the laboratory?
As the name suggests, the main studies conducted in our laboratory concern physical volcanology and petrology. As far as physical volcanology is concerned, with different methods of investigation we try to reconstruct the physical processes that occur before and during an eruption but also the ways in which the volcanic deposits are put into place. Petrological investigations, on the other hand, allow us to decipher some physical and chemical problems inherent in the genesis of magmas, their ascent in the earth's crust as well as the interaction that magmas themselves can have with the rocks they pass through.
What kind of investigations are carried out in the laboratory?
The laboratory carries out sedimentological investigations on pyroclastic rocks (for example granulometric and component analyses), mineralogical analyzes (such as the study of the nature, abundance and composition of minerals contained in volcanic rocks) and geochemical analyzes on volcanic rocks from volcanoes Italian and foreign (for example from the Canary Islands, the Azores Islands, the Antarctic volcanoes, Patagonia or Iceland), in the study of which the researchers of the Pisa Section have always been engaged. As far as petrological investigations are concerned, in some cases the presumed conditions in which the magmas were generated are even reproduced, simulating their chemical composition but also the pressure and temperature in the laboratory and then observing their evolution over time and as these vary parameters.
What equipment do you use for your studies?
The laboratory is equipped with numerous tools necessary for the preparation and study of rocks in the volcanological and petrological fields.
Can you give us some examples?
Yes, of course, a vibrating-oscillating mechanical sieve coupled to a series of 10 and 20 cm diameter metal sieves, used to determine the granulometric characteristics - both by wet and dry processes - of loose pyroclastic rocks. This sieve shaker is equipped with two ovens for drying the samples. We also have instruments for the impregnation (consolidation), embedding, cutting and polishing of rock samples, a system for the separation of phases (minerals) based on the density contrast (separation with heavy liquids), some optical and stereo microscopes - microscopes for the morphological, morphometric and petrographic study of loose volcanic rocks and in thin sections, and a furnace for petrological-experimental studies at high temperatures (up to 1400° C) and atmospheric pressure.