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The caldera-forming eruption of the Tufo Rosso a Scorie Nere (RNR): insight from geological fieldwork and geochemistry

Alessandro Frontoni 1,3, Guilherme Gualda2, Andrea Bonamico3, Cioni Raffaello4, Sandro Conticelli1,4, Guido Giordano1,3

  • Affiliations: 1 Institute of Environmental Geology and Geoengineering - National Research Council of Italy (CNR); 2 Earth and Environmental Sciences - Vanderbilt University - 2301 Vanderbilt Place - Nashville - TN - 37235 - USA; 3 Department of Science - Section of Geology - University of Roma Tre - Viale Guglielmo Marconi 446 - 00146 -- Rome; 4 Dipartimento di Scienze della Terra - Università degli studi di Firenze - Via Giorgio La Pira - 4 - Firenze I-50121 - Italy;

  • Presentation type: Poster

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

  • Poster Board Number: 59

  • Programme No: 3.11.19

  • Theme 3 > Session 11

Abstract

The Tyrrhenian margin of Italy is the site since the Quaternary of intense K-alkaline magmatism. Several intermediate to large volume caldera-forming eruptions have occurred from nine caldera systems. The Sabatini Volcanic District hosts two calderas, the Bracciano and the Sacrofano calderas, which generated large ignimbrites. The largest of these eruptions issued from the Bracciano caldera and emplaced the Tufo Rosso a Scorie Nere ignimbrite (RNR), dated ca. 452 ka and associated with the first caldera-forming event of the district. The new geological mapping of the RNR ignimbrite allows us to quantify the erupted bulk volume calculated at 223 km3 (138 km3 DRE), which makes this a VEI6 eruption and the second of the Roman Magmatic Province after the 600 km3(265 km3 DRE) of the 39 ka Campanian Ignimbrite from Campi Flegrei caldera. Geochemical characterization of the glass allows us to test the efficiency of the residual glass geobarometry analysis with rhyolite-MELTs, and discuss the geometry and structure of the plumbing system leading to the RNR caldera-forming event.