Francesca Forni

GMPV Geochemistry, Mineralogy, Petrology & Volcanology

The 2016 Outstanding Student Poster and PICO (OSPP) Award is awarded to Francesca Forni for the poster/PICO entitled:

The origin of a zoned ignimbrite: insights into the Campanian Ignimbrite magma chamber (Campi Flegrei, Italy) (Forni, F.; Bachmann, O.; Mollo, S.; De Astis, G.)

Click here to download the poster/PICO file.

I’m a PhD student in the volcanology and magmatic petrology group at the Institute of Geochemistry and Petrology (ETH, Zürich). I’m mainly interested in investigating the mechanisms of onset and evolution of silicic upper crustal magma reservoirs. At EGU I presented the results of a recent work about the Campanian Ignimbrite, erupted at Campi Flegrei about 39 ka during the largest caldera-forming eruption of the Mediterranean area over the last 200 ka. The Campanian Ignimbrite is a voluminous pyroclastic sequence showing remarkable crystallinity, geochemical and thermal gradients, attributed to eruption from a vertically zoned magma chamber. We interpreted these gradients as the result of protracted fractional crystallization leading to the formation of a cumulate mush at the base of the eruptible reservoir, from which highly-evolved, crystal-poor, water-rich and relatively cold melts were separated. The extracted melts, forming a buoyant, easily eruptible cap at the top of the magma chamber, fed the initial phases of the eruption, until caldera collapse and eruption of the deeper more crystalline part of the system. This late-erupted, crystal-rich material represents remobilized portions of the cumulate crystal mush, partly melted following hotter recharge.