The “One-hundred horses cave” and the “Cave of the hermit” in the Medium and Lower Alcantara Valley (North eastern Sicily)

Abstract

In the territory of San Cataldo, a hamlet of Motta Camastra (ME), near the "Bridge of Mitogio" which joins the two banks of the Alcantara River, there are some lava flow caves, known as "Grotta dei Cento Cavalli" and "Grotta dell’Eremita". The caves, currently little known, were the refuge of famous brigands who marked, even in illegality, important pages of local history of the fifteenth and sixteenth centuries. The oral evidence handed down suggests that the studied caves are part of a more complex system of underground cavities of which they remain the only sign, as one or more cavities were artificially buried by the peasants for unspecified reasons, while others would have been detonated with dynamite to flush out the bandits who were hiding there. From the geological point of view, the study of the two caves brings new important elements in the knowledge of the genesis of the lavas that emerge in the middle and lower Alcantara Valley, as the study of the morphometry of the cavities and of the spatial articulation of the same, as well as other considerations on the geomorphological evolution of the places, it was possible to identify the eruptive center that generated them a few tens of meters to the north-east. This work adds an important piece to understand the volcanological mechanisms that allowed the emergence of eusive activities in an area so peripheral to the Etna volcanic edifice, and implement what recently published by one of the authors (Di Marco Sergio, 2016), which had already identified about two kilometers further upstream, in the locality "Gole dell’Alcantara"(The Gorges of Alcantara), another lava emission center. The identification of another eruptive center, allows to frame the eruptive fissure of the Alcantara Gorges no longer as a "punctual" event of peripheral Etna volcanism, but allows to delineate a more complex system of tectonic dislocations structured within the fluvial valley, and used by deep magmas as a way of ascending to the surface. In this work was privileged the descriptive part of the caves, in order to better distinguish the data collected in the field with the hypotheses that derive from it. We refer to a following work for a more organic description of the geology of the sites and of the volcanological and tectonic-structural factors justifying eusive events in such a peripheral area and beyond the northern limit of the Etna volcano edifice.