Volcanic facies associations in a modern volcaniclastic apron (Lipari and Vulcano offshore, Aeolian Island Arc)

Abstract

Multibeam bathymetric and reflectivity data, high-resolution sidescan sonar mapping and ROV images have allowed reconstruction of the present-day facies distribution within the volcaniclastic apron offshore from Lipari and Vulcano. Primary volcanic, resedimented volcaniclastic and volcanogenic sedimentary facies have been distinguished. Primary volcanic facies are volumetrically subordinate but play a major role in controlling the distribution of the other facies and the development of the main submarine canyons, and as the source of volcanic detritus in resedimented volcaniclastic facies. Erosion and transport prevail in the canyons. Conversely, deposition of volcanogenic sediments, in response to flow spreading and gradient reduction, occurs at the canyon mouths. The influence of the adjacent islands on the offshore processes is particularly evident in the area facing the active sector of Vulcano Island. Here, large volumes of volcanogenic sediment from the emergent volcanic edifice are transferred downslope by subaqueous gravity flows allowing the construction of a volcaniclastic fan.