Skip to content

Upper Miocene volcanic ash layers from central Italy: tracking down the volcanic source

Matteo Roverato1, Federico Farina3, Matteo Lupi2, Maria Ovtcharova2, Alessandro Montanari4, Marco Bonini5; Domenico Montanari5.

  • Affiliations: 1-      Department Bigea, Alma Mater Studiorum, University of Bologna, Italy 2-      Department of Earth Sciences, University of Geneva, Switzerland 3-      Department of Earth Sciences \"Ardito Desio\", University of Milan, Italy 4-      Osservatorio Geologico di Coldigioco, Cda. Coldigioco 4, 62021 Apiro, Italy 5-     CNR, Institute of Geosciences and Earth Resources, Florence, Italy 

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 140

  • Programme No: 3.13.9

  • Theme 3 > Session 13

Abstract

Since the Eocene, the Mediterranean region has experienced intense explosive volcanism. These eruptions ejected tephra, including fine-grained ash, which was dispersed widely through the air before settling as ash layers. Many of these layers are preserved in continental and marine sedimentary basins, offering crucial insights into historical volcanic activity. However, identifying the sources of numerous ash layers remains a significant challenge. In central Italy, the presence of numerous ash layers is well-documented in the literature, but their specific volcanic origins are often uncertain. In this study, we analyze upper Tortonian (~7.6 Ma) ash layers sampled from three distinct localities spanning from the Tyrrhenian to the Adriatic coasts of Italy. Our findings are compared with previously described data in the literature. Using electron microprobe geochemical analyses of biotite crystals, U-Pb ID-TIMS and LA-ICP-MS geochronological dating, and trace elements/Lu-Hf isotope analyses on zircons, we enhance our understanding of these ancient ash deposits. Several volcanic centers were active during the late Tortonian, including the Massif Central (France), the Valencia Trough (Spain), the Betics-Rif orogen (Spain-Morocco), the eastern Carpathians (Romania), and Capraia Island (Italy). Through precise radioisotopic dating and geochemical comparison, we identify the Upper Miocene Capraia Island volcano (Tuscan Archipelago) in the northern Tyrrhenian basin as the most likely source of these ash layers.