Evidence of slope instability in the Southwestern Adriatic Margin
نویسنده
چکیده
The Southwestern Adriatic Margin (SAM) shows evidence of widespread failure events that generated slide scars up to 10 km wide and extensive slide deposits with run out distances greater than 50 km. Chirp-sonar profiles, side-scan sonar mosaics, multibeam bathymetry and sediment cores document that the entire slope area underwent repeated failures along a stretch of 150 km and that masstransport deposits, covering an area of 3320 km2, are highly variable ranging from blocky slides to turbidites, and lay on the lower slope and in the basin. The SAM slope between 300–700 m is impacted by southward bottom currents shaping sediment drifts (partly affected by failure) and areas of dominant erosion of the seafloor. When slide deposits occur in areas swept by bottom currents their fresh appearence and their location at seafloor may give the misleading impression of a very young age. Seismic-stratigraphic correlation of these deposits to the basin floor, however, allow a more reliable age estimate through sediment coring of the post-slide unit. Multiple buried failed masses overlap each other in the lower slope and below the basin floor; the most widespread of these mass-transport deposits occurred during the MIS 2-glacial interval on a combined area of 2670 km2. Displacements affecting Holocene deposits suggest recent failure events during or after the last phases of the last postglacial eustatic rise. Differences in sediment accumulation rates at the base or within the sediment drifts and presence of downlap surfaces along the slope and further in the basin may provide one or multiple potential weak layers above which widespread collapses take place. Neotectonic activity and seismicity, together with the presence of a steep slope, represent additional elements conducive to sediment instability and failure along the SAM. Evidence of large areas still prone to failure provides elements of tsunamogenic hazard. Correspondence to: D. Minisini ([email protected])
منابع مشابه
Upper Turonian – Santonian slope limestones of the Islands of Premuda , Ist and Silba ( Adriatic Coast , Croatia )
Upper Turonian–Santonian limestones at three island locations (Ist, Silba and Premuda) in the southwestern part of the Adriatic carbonate platform, record slope deposition based on their sedimentological and palaeontological characteristics. These Upper Cretaceous successions consist of three vertically superimposed lithotypes: (1) pelagic mudstonespackstones, (2) laminated pelagic wackestones-...
متن کاملLate spring characterization of different coastal areas of the Adriatic Sea
The objective of this study is to analyze the physical and chemical characteristics of three coastal zones of the Adriatic Sea during late spring, and to identify similarities and differences among the zones. The trophic status of the Southeastern Adriatic-Sea, dominated by the discharge from the Buna/Bojana river delta watersheds, is compared with two other Adriatic regions: the Northwestern A...
متن کاملA Novel Indicator to Predict the Onset of Instability of a Gravitational Flow on a Slope
In order to present a quantitative indicator for the onset of instability, in this paper, the critical points of a stratified gravitational flow on a slope are found and analyzed. These points are obtained by means of the solution of the two-dimensional Navier-Stokes equations via the standard Arakawa-C finite-difference method. Results show that in the marginal Richardson numbers, the critical...
متن کاملThe Northeastern Margin of the Adriatic Carbonate Platform
The evolution of the northern margin of the Adriatic Carbonate Platform (AdCP) can be reconstructed for the period between the Early Jurassic and the Early Palaeogene. Its recent strike is NW–SE (DRAGIČEVIĆ & VELIĆ, 1994) and can be followed from the Slovenian basin (near Tolmin in Slovenia) extending all the way to the Krasta–Cukali–Budva trough in northern Albania The Northeastern Margin of t...
متن کاملEvaluation soil erodibility in catchment of Torogh dam of Mashhad
Extended abstract 1- Introduction Soil erosion is one of the most important problems in the arid and semi-arid areas in Iran and the knowledge about its content has an important role on the management practices of soil conservation. Topography as one of the soil-making factors affects the physical properties of the soil through the aspect and the degree of the slope. The aspect of the slope c...
متن کامل