Explosive volcanic activity recorded in a Pleistocene hot spring system: an example from central Italy.
Federica Barilaro 1,2, Andrea Di Capua 2, Paola Donato 1
Affiliations: 1 Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende (CS), Italy. 2 CNR -- IGAG, Milano, Italy.
Presentation type: Talk
Presentation time: Tuesday 15:00 - 15:15, Room R280
Programme No: 3.5.8
Abstract
Explosive volcanic activity has played a pivotal role in shaping Earth's geological history, leaving distinct imprints in the rock record. During such events, magma ascent and eruption produce vast quantities of particles that are either ejected into the atmosphere or transported through surface processes into surrounding environments. As these represent relative short-lived events, identifying primary volcaniclastic deposits is critical for reconstructing detailed volcanic history and assessing its impact on the adjacent environments. However, these deposits may exhibit a low preservation potential, complicating their identification and differentiation from other volcaniclastic units. A major challenge in fossil deposits is distinguishing primary volcanic products from secondary materials formed by the weathering of antecedent materials. This issue is complicated when pyroclastic deposits, both air-fall and flow, interact with water in continental and marine environments, leading to potential misidentification or omission in the geological record. While primary pyroclastic deposits have been extensively studied in marine and lacustrine environments, terrestrial hot spring systems remain underexplored as records of explosive volcanic activity. This study investigates primary volcaniclastic deposits (from PDC and fallout events) within a fossil hot spring system in Southern Tuscany, Central Italy, offering the first comprehensive overview of their accumulation, alteration processes, and preservation potential in such environments. Petrographic analysis and high-resolution electron microscopy revealed significant post-depositional alteration of pyroclastic features and secondary (bio)minerals formation. These findings highlight the potential of hot spring systems to preserve volcanic records, enhancing our understanding of eruptive histories and regional geological evolution.