The Malta-Sicily Escarpment: Mass Movement Dynamics in a Sediment-Undersupplied Margin

Abstract

The Malta-Sicily Escarpment (MSE) is a steep carbonate escarpment that appears to have largely remained isolated from inputs of fluvial and littoral sediments since the Messinian Salinity Crisis. Mass movement activity has so far only been inferred from sediment cores at the base of the MSE. In this study we use geophysical and sedimentological data acquired from the upper MSE and outer Malta Plateau to: (i) map and characterise the dominant forms of mass movements, and (ii) determine the nature and origin of these mass movements, and their role in the evolution of the MSE. We document 67 mass movement scars across 370 km 2 of seafloor. Slope instability entailed translational slides, spreads and debris flows that mobilised Plio-Pleistocene outer shelf hemipelagic/pelagic sediments or carbonate sequences across the upper continental slope. Slope failure events are caused by loss of support associated with the formation of channels, gullies, canyon heads and fault-related escarpments. Mass movements play a key role in eroding the seafloor and transferring material to the lower MSE. In particular, they control the extent of headward and lateral extension of submarine canyons, facilitate tributary development, remove material from the continental shelf and slope, and feed sediment and drive its transport across the submarine canyon system.

First report of live deep-water cnidarian assemblages from the Malta Escarpment

“…Swath bathymetry data were acquired from 370 km 2 of seafloor using a Kongsberg Simrad EM710 multibeam echosounder with a nominal sonar frequency of 70-100 kHz (Micallef et al 2013). An ROV dive was carried out to obtain video footage and still photographs of small-scale morphology, benthic habitats and biota from the canyon heads in order to ground-truth the acoustic data.…”

“…Landslide activity across the Malta Escarpment had mainly been inferred from sediment cores, with turbidites, megaturbidites and debris flows being reported from the base of the Malta Escarpment (Scandone et al 1981;Casero et al 1984;Rebesco et al 2000). More recently, submarine landslides, in the form of translational slides, spreads and debris flows, have been shown to be a widespread geomorphologic phenomenon across the outer Malta Plateau and upper Malta Escarpment (Micallef et al 2013). The outer Malta Plateau also hosts four channels and a number of straight to non-linear bedrock ridges (Micallef et al 2013).…”

“…More recently, submarine landslides, in the form of translational slides, spreads and debris flows, have been shown to be a widespread geomorphologic phenomenon across the outer Malta Plateau and upper Malta Escarpment (Micallef et al 2013). The outer Malta Plateau also hosts four channels and a number of straight to non-linear bedrock ridges (Micallef et al 2013). …”

Earthquake-triggered landslides along the Hyblean-Malta Escarpment (off Augusta, eastern Sicily, Italy) – assessment of the related tsunamigenic potential

“…Dense seismic profiles have shown that, onshore and offshore, the region is characterized by three main well-defined sediment layers and a complex system of faults (Argnani et al, 2002) where the E1693 hypocentre could be well accomodated. The three layers are, (i) the Mesozoic carbonate sediment, (ii) the Cenozoic basin sediments and (iii) the Plio-Quaternary sediments (Argnani and Bonazzi, 2005;Micallef et al, 2014). The last layer composes the seafloor and we assume that the sliding mass could have involved only sediments of the Quaternary Period.…”

Submarine Mass Movements and their Consequences

“…In this paper we address the hypothesis that, by influencing pore pressure in sub-seafloor sediment, shallow gas can promote the development of a weak layer above which submarine spreading can occur. Nevertheless, the characteristic submarine spreading morphology, in the form of a recurring pattern of ridges and troughs, can be observed in numerous submarine landslides around the world (Lastras et al 2003(Lastras et al , 2006Micallef et al 2013;Piper et al 1999;. 42.1).…”