A new geological map of Stromboli volcano (Tyrrhenian Sea, Italy) based on application of lithostratigraphic and UBS units

A new geological map of the island of Stromboli at a scale of 1:10,000 is here presented based on 1:5000 scale field mapping, carried out in the years 1991-2001, by applying exclusively lithostratigraphic criteria and unconformity-bounded stratigraphic (UBS) units. The application of UBS units proved to be very effective, especially in such a complex succession of volcanic rocks. In total, 45 lithostratigraphic units and eight synthems, as well as various subsynthems, lithosomes, and units representing the most recent sedimentary deposits, were recognized. The resulting legend for the 1:10,000 map has been elaborated in such a way as to distinguish the lithostratigraphic units occupying a well-defined stratigraphic position from the ones for which stratigraphic attribution is uncertain; furthermore, the range of possible stratigraphic positions is also indicated. Other problems are discussed and solutions proposed, such as: (1) representing and distinguishing historic deposits that do not have any lithologic or geometric variations with respect to the recent deposits above which they have been emplaced, (2) representing units, or boundaries between units, that crop out only on vertical cliffs, (3) possible scale reduction, and (4) the cartographic problems related to structural features. Finally, the main differences from previous modern maps are described in terms of the geological evolution of Stromboli volcano, one of the best-documented examples of a multiple-collapse edifice