Vulcano is the southernmost island of the Aeolian Archipelago in the Southern Tyrrhenian Sea and represents the tip of a large stratovolcano that rises from ? 1000 mbsl. Its northern sector is dominated by La Fossa Caldera, whose northeastern part lies underwater and has been deeply eroded and breached. The dismantling of the caldera rim and infill has fed a large volcaniclastic fan in the offshore through repeated mass-wasting events. A multi-disciplinary approach was used to infer the main sedimentary processes acting in this submarine sector through the integration of a large dataset of marine geophysical data (multibeam, side scan sonar and seismics) and the results of sedimentological and micropaleontological analyses of seafloor samples. Overall, the northeastern submarine flank of Vulcano is mostly covered by relatively coarse-grained volcaniclastic sediments, resulting from sediment-laden gravity flows; this highenergy sedimentary system is able to transport fine and medium sand over 1100 m down to the Stromboli Canyon. In detail, three morpho-sedimentary zones were recognized from the coastal sector to the offshore, each of them characterized by one (or more) prevalent reworking and transport processes: the first one corresponds to the highly incised submerged prosecution of La Fossa and is characterized by rock falls/avalanches and granular inertial flows. The second zone is represented by the wide Baia di Levante Fan system, where turbiditic sedimentation prevails, whereas the third zone encompasses most part of the lower submarine flank of Vulcano and the sedimentary highs located both inside and outside the BLF system, being dominated by hemipelagic deposition.
Study of mass-wasting processes offshore NE Vulcano (Aeolian Islands): A multidisciplinary approach
D Casalbore;FL Chiocci
2012
Abstract
Vulcano is the southernmost island of the Aeolian Archipelago in the Southern Tyrrhenian Sea and represents the tip of a large stratovolcano that rises from ? 1000 mbsl. Its northern sector is dominated by La Fossa Caldera, whose northeastern part lies underwater and has been deeply eroded and breached. The dismantling of the caldera rim and infill has fed a large volcaniclastic fan in the offshore through repeated mass-wasting events. A multi-disciplinary approach was used to infer the main sedimentary processes acting in this submarine sector through the integration of a large dataset of marine geophysical data (multibeam, side scan sonar and seismics) and the results of sedimentological and micropaleontological analyses of seafloor samples. Overall, the northeastern submarine flank of Vulcano is mostly covered by relatively coarse-grained volcaniclastic sediments, resulting from sediment-laden gravity flows; this highenergy sedimentary system is able to transport fine and medium sand over 1100 m down to the Stromboli Canyon. In detail, three morpho-sedimentary zones were recognized from the coastal sector to the offshore, each of them characterized by one (or more) prevalent reworking and transport processes: the first one corresponds to the highly incised submerged prosecution of La Fossa and is characterized by rock falls/avalanches and granular inertial flows. The second zone is represented by the wide Baia di Levante Fan system, where turbiditic sedimentation prevails, whereas the third zone encompasses most part of the lower submarine flank of Vulcano and the sedimentary highs located both inside and outside the BLF system, being dominated by hemipelagic deposition.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.