Fluid escape structures in the Graham Bank region (Sicily Channel, Central Mediterranean) revealing volcanic and neotectonic activity

In the Sicily Channel, (Central Mediterranean), two geodynamic processes overlap each other, the Maghrebides- Apennines accretionary prism and the Sicily Channel rift. Moreover, the northwestern sector (Banks sector) is characterised by an irregular seafloor morphology linked to the recent volcanic and tectonic activity.In order to discriminate the role exerted by both the processes in the morphostructural setting of the area we used a dataset of both high and very high resolution single-channel and multi-channel profiles, acquired in the frame of the RITMARE project respectively with CHIRP and sparker, and airgun sources, and high resolution (5 m cell) morpho-bathymetric data. The data all…

First Evidence of Contourite Drifts in the North-Western Sicilian Active Continental Margin (Southern Tyrrhenian Sea)

We present the results of an integrated geomorphological and seismo-stratigraphic study based on high resolution marine data acquired in the north-western Sicilian continental margin. We document for the first time five contourite drifts (marked as EM1a, EM2b, EM2, EM3a, and EM3b), located in the continental slope at depths between ca. 400 and 1500 m. EM1a,b have been interpreted as elongated mounded drifts. EM1a,b are ca. 3 km long, 1.3 km wide, and have a maximum thickness of 36 m in their center that thins northwards, while EM1b is smaller with a thickness up to 24 m. They are internally characterized by mounded seismic packages dominated by continuous and parallel reflectors. EM2 is loc…

How Offshore Groundwater Shapes the Seafloor

The MARCAN project, launched last January, is working to fill a gap in our knowledge of how freshwater flowing underground shapes and alters the continental margins.

Seismic stratigraphy of the north-westernmost area of the Malta Plateau (Sicily Channel): The Middle Pleistocene-Holocene sedimentation in a tidally influenced shelf

In this study we present the results of a seismic-stratigraphic analysis of sub-bottom profiles in the north-westernmost area of the Malta Plateau in order to define the depositional mechanisms for the upper Quaternary sequences. During this interval the morphology of the Malta Plateau was characterized by a ramp and bathymetries not exceeding 200 m. Two major unconformities, related to MIS 6 and MIS 2 (the latter corresponding to the Last Glacial Maximum, LGM), characterize the upper Quaternary sequences. The geometries of the recognized seismic units indicate as depositional mechanisms were controlled by subsidence and sea-level fluctuations. In detail, deposits related to the last glacia…

Evidence of active fluid seepage (AFS) in the southern region of the central Mediterranean Sea

Abstract Active fluid seepage (AFS) at the seafloor is a global phenomenon associated with seafloor morphologies in different geodynamic contexts. Advanced geophysical techniques have allowed geoscientists to characterise pockmarks, mounds and flares associated with AFS. We present a range of new marine geological data acquired in the southern region of the central Mediterranean Sea (northern Sicily continental margin, northwestern Sicily Channel and offshore of the Maltese Islands), which allow us to identify AFSs. AFSs are spatially distributed as clusters, aligned or isolated at different depths, ranging from few decametres offshore of the Maltese Islands; up to 400 m offshore of norther…

A scenario-based assessment of the tsunami hazard in Palermo, northern Sicily, and the southern Tyrrhenian Sea

Depositional mechanism of the upper Pliocene-Pleistocene shelf-slope system of the western Malta Plateau (Sicily Channel)

Abstract A high resolution seismic stratigraphic study of the western edge of the Malta Plateau (central Mediterranean Sea) was conducted to reconstruct the depositional mechanisms of the shelf-slope system since the end of the Messinian salinity crisis (MSC; 5.3 Ma). The accurate interpretation of a large grid of variable-resolution seismic reflection profiles (multichannel and Sub Bottom) allows us to identify and map a Plio-Quaternary sedimentary sequence overlying the Messinian evaporites. The stratal pattern of this sequence is the result of a clinoform prograding system that constitutes the internal structure of a sedimentary shelf developed in a ramp about 2° slope with bathymetries …

The Graham Bank (Sicily Channel, central Mediterranean Sea). Seafloor signatures of volcanic and tectonic controls

Abstract Graham Bank is a dominant physiographic element of the NW Sicily Channel (central Mediterranean Sea), affected in the last 100 years by numerous well-documented volcanic eruptions. We present the first results of a geomorphological study where the Graham Bank region in the depth interval 7–350 m was mapped for the first time with multi-beam echosounder and high-resolution seismic and multi-channel seismic reflection profiles. We describe in high resolution the detailed geomorphological features of Graham Bank, and how the superficial expression of different process and dynamics occurring in the sub-seafloor evidence volcanic and tectonic controls on seafloor morphology across a rel…

Evidence of the Zanclean megaflood in the eastern Mediterranean Basin

A. Micallef et. al.

New foundings of contourite deposits in an active continental margin (Southern Tyrrhenian Sea)

Growth and geomorphic evolution of the Ustica volcanic complex at the Africa-Europe plate margin (Tyrrhenian Sea)

18 pages, 13 figures, 1 table