Elisabetta Campiani

Bathymetry of the Adriatic Sea: The legacy of the last eustatic cycle and the impact of modern sediment dispersal

The Istituto di Scienze Marine (ISMAR-CNR) has conducted several research projects on the Italian side of the Adriatic Sea over more than 15 years, collecting bathymetric, geophysical and sediment core data to perform multidisciplinary studies of modern sediment dynamics and of past environmental changes during the last eustatic cycle. A crucial step in this direction was the construction of a detailed bathymetry, a time-consuming task due to the extensive shallow water portion of the basin. Given the setting of the Adriatic Sea and the long-lasting research effort, the bathymetric map is necessarily based on heterogeneous data with uneven spatial distribution of Single-Beam echo-soundings. The main objective of this work is to illustrate the methodology applied to compile the bathymetric map of the west side of the Adriatic Sea at basin scale (1:750,000) and to describe the main morphological units that characterise the seafloor and reflect its main geological features. This bathymetry can also be used in oceanographic modelling both at regional and local scale, focussing on the interaction between bottom currents and seafloor morphology.

DROWNED KARST LANDSCAPE OFFSHORE THE APULIAN MARGIN (SOUTHERN ADRIATIC SEA, ITALY)

The south Adriatic shelf offshore of the predominently carbonate Apulian coast is characterized by a peculiar rough topography interpreted as relic karst formed at a time of lower sea level. The study area covers a surface of about 220 km, with depths ranging from 50 to 105 m. The most relevant and diagnostic features are circular depressions a few tens to 150 m in diameter and 0.50 to 20 m deep thought to be dolines at various stages of evolution. The major doline, Oyster Pit, has its top at about 50 m water depth and is 20 m deep. It is partly filled with sediments redeposited by episodic mass failure from the doline’s flank. Bedrock samples from the study area document that Plio-Pleistocene calcarenites, tentatively correlated with the Calcarenite di Gravina Fm, are a prime candidate for the carbonate rocks involved in the karstification, although the presence of other units, such as the Peschici or Maiolica Fms, is not excluded. The area containing this subaerial karst landscape was submerged about 12,500 years ago as a result of the postglacial transgression over the continental shelf.

Mass Transport Complexes from Contourite and Shelf-Edge Deposits Along the South-Western Adriatic Margin (Italy)

Seismic data and multi-beam bathymetry reveal the occurrence of several exposed or shallowly buried Mass Transport Complexes (MTCs) in the South-Western Adriatic margin (SWAM), which represents the outer sector of the Albanides-Dinarides foreland basin. MTCs are spatially diffused along the SWAM and characterized by high variability in size, morphology and internal geometry. MTCs are derived from the mobilisation of both contourite drift deposits and shelf-margin progradational deposits. The most prominent MTC of the SWAM is the Gondola Slide (GS), a large, deep-seated (∼250 m) MTC located near the Gondola-Dauno fault zone (GDFZ), involving around 30 km3 of shelf and slope sediments. In the northern sector of the margin, the Vieste Slide (VS) affects a low gradient upper slope sector, which is extensively dominated by contourite drifts and sediment waves. Seismic correlation shows that the first and main failure events of GS and VS were contemporaneous and impacted the entire margin (more than 2,000 km2), and probably were trigger by large earthquake, while later events in both GS and VS appear more localised and asynchronous indicating, probably, slope readjustments governed by local stratigraphic factors.

High resolution multibeam and hydrodynamic datasets of tidal channels and inlets of the Venice Lagoon

Tidal channels are crucial for the functioning of wetlands, though their morphological properties, which are relevant for seafloor habitats and flow, have been understudied so far. Here, we release a dataset composed of Digital Terrain Models (DTMs) extracted from a total of 2,500 linear kilometres of high-resolution multibeam echosounder (MBES) data collected in 2013 covering the entire network of tidal channels and inlets of the Venice Lagoon, Italy. The dataset comprises also the backscatter (BS) data, which reflect the acoustic properties of the seafloor, and the tidal current fields simulated by means of a high-resolution three-dimensional unstructured hydrodynamic model. The DTMs and the current fields help define how morphological and benthic properties of tidal channels are affected by the action of currents. These data are of potential broad interest not only to geomorphologists, oceanographers and ecologists studying the morphology, hydrodynamics, sediment transport and benthic habitats of tidal environments, but also to coastal engineers and stakeholders for cost-effective monitoring and sustainable management of this peculiar shallow coastal system.