The earliest products of Etna volcano (Sicily, Italy) crop out in the lower east flank of the edifice and offshore, along the Ionian coast, north of Catania. They are pillow lavas and hyaloclastic breccia about 500 ka old (Acicastello area, De Beni et al., 2011) and subvolcanic bodies (Cyclopean islands, Acitrezza area) intruded in the early-middle Pleistocene marl clays, whose age is still under debate. The main subvolcanic body is a laccolite. It crops out offshore the Acitrezza village forming the Lachea Island that is a famous touristic attraction. Such place shows slow-cooling columnar basalts in stratigraphic contact with overlying clays. The Lachea Island is part of a series of outcrops off shore and in land of Acitrezza that have been interpreted as remains of a wider subvolcanic body intersected by several normal fault (Corsaro and Cristofolini, 1997 and references therein).
Despite the Cyclopean Islands have been studied in the last decades, a crucial and intriguing scientific still open question is: do they really belong to the “Basal tholeiitic” stage of the Geological map of Etna volcano (Branca et al., 2011). To know more, a geological and magmatological study of the area is ongoing to better understand stratigraphic position and role of Cyclopean Islands in the evolution of Etnean magmatism.
Credits: Model description by Emanuela De Beni; Photo collection, photogrammetry processing and 3D Model are from: Emanuela De Beni, Massimo Cantarero – INGV Osservatorio Etneo. The 3D model of the Lachea island has an extent of 230 x 200 m, has been generated after a UAV survey performed in July 2018, overflying the island at 30 m height and elaborating 261 images.
This work is the results of an agreement between INGV and the CUTGANA of Catania University, signed in March 2018, with the aim to increase the geological knowledge of the “Riserva Naturale Integrale Isola Lachea e Faraglioni dei Ciclopi” and its surroundings, to promote geoscience popularization among citizens, as well as for tourism promotion purposes. We would like to thank Rosa Anna Corsaro and Domenico Catalano, the main actors of this agreement.
- Branca S., Coltelli M., Groppelli G., Lentini F. (2011) Geological map of Etna volcano, 1:50,000 scale. Ital. J. Geosci., 130 (3), 265-291.
- Corsaro R.A. and Cristofolini R. 1997. Geology and geochemistry and mineral chemistry of tholeiitic to transitional Etnean magmas. Acta Vulcanologica – Vol. 9 (1/2) -1197-: 55-66
- De Beni, E., Branca, S., Coltelli, M., Groppelli, G., Wijbrans, J.R., 2011. 39Ar/40Ar isotopic dating of Etna volcanic succession. Italian Journal Geosciences Bolletino della Società Geologica of Italy 130 (3), 292–305.