Geological map of Etna volcano, 1:50,000 scale

Stefano Branca(*), Mauro Coltelli(*), Gianluca Groppelli(**) & Fabio Lentini(***)
(*) Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo, sezione Catania, Piazza Roma, 2 - 95125 Catania (Italy). Corresponding authors: phone: +390957165800; e_mail: stefano.branca@ct.ingv.it (**) C.N.R - Istituto per la Dinamica dei Processi Ambientali, sezione di Milano, Via Mangiagalli, 34 - 20133 Milano (Italy). (***) Dipartimento di Scienze Geologiche, Università di Catania, Corso Italia, 55 - 95129 Catania (Italy).

The new geological map of Etna volcano at 1:50,000 scale represents a significant progress in the geological studies of this volcano over the last 30 years, coming after Waltershausen's map published around the mid of 19th century, the first geological map of a large active volcano, and the ROMANO et alii (1979) map published about a century later, both at 1:50,000 scale. Lithostratigraphy was used for mapping volcanic units and then Unconformity Bounded Units were applied to group lithostratigraphic units into synthems. In addition, lithosomes were exploited to better represent the spatial localization of different eruptive centres according to their morphology. On the whole, we identified 27 lithostratigraphic units, grouped into 8 synthems, and 9 volcanoes. In detail, effusive and explosive deposits generated by each eruption of Mongibello and, partially, Ellittico volcanoes were mapped as flow rank. This stratigraphic framework represents the best synthesis of the geological evolution of Etna volcano using the main unconformities recognized within its complex volcanic succession. In addition, we constrain the Etna volcanic succession and its lithostratigraphic units chronologically by radioisotope age determinations. On the basis of the outlined synthemic units, it was possible to divide Etna's volcanic succession into 4 supersynthems, which correspond to 4 well-defined and spatially localized phases. The detailed reconstruction of the past eruptive activity allowed compiling the most accurate dataset in particular of the Holocene eruptions of Etna volcano, which will enable significantly improving the volcanic hazard assessment, together with petrological interpretation of erupted magmas and geophysical modeling of the volcano plumbing system.

Mount Etna, geological map, basaltic composite volcano, stratigraphy, UBU.