Within the framework of the METIQ project, our unit mapped the deepest parts of the Northern and Southwestern Tyrrhenian Sea, and the Eastern Sardinian and North-eastern Sicilian margins. Quaternary elements develop in extremely different physiography settings, which are the response to deep processes occurring in different geodynamic and tectonic contexts, from active to passive margins, from deforming and quiescent rifts, to ocean-like back-arc basins. Large areas of the external continental shelf lack any Holocene deposit, and thus a series of submerged coastal systems record the pace and the outcomes of the last sea-level transgression. Canyons span a range of morphologies, which illustrate general rules for their evolution, from inception and erosion to infill and deposition. At the base of slope, canyons often join leveed-channels, whose planform and architecture varies depending mainly on the tectonic history of the margins. Both canyons and channels have internal elements related to the processes of sediment feeding and routing to the deep-sea. Fans have different dimensions, shape and relative importance of smaller morphologic constituents. Landslides are a major feature in all the sectors of the mapped area. Mapping has shown the variety of sediment collapses mechanisms, comprehensive of the complete removal of thin, surficial extensive layers, glacial-like, slow downslope movements, and large margin collapses with multiple failure episodes. Pockmark fields are present in many of the seamounts of the northern Tyrrhenian Sea and on the continental slope of Sardinia and Sicily. Their distribution is sometimes controlled by active tectonics, while in others, a possible relationship with the distribution of surficial sedimentary units is apparent. Particularly in the Northern Tyrrhenian area, contour currents shape some portions of the continental slope and the infill of intraslope basins; moreover, they appear to influence the degree of sedimentary cover on seamount top. A reappraisal of Quaternary and active tectonics shows various belts indicating a recent spatial focussing of extensional tectonics within the extended Tyrrhenian Sea. Various new volcanic buildings have been highlighted, particularly in the Sardinia margin and in the northern Tyrrhenian Sea, contributing to the enlargement of the extent of the magmatic provinces of the Tyrrhenian-Apenninic region. In general, our mapping stands out as a reminder of the importance of a basic description and understanding of the physical character of the submarine territory. Our results indicate that, with the METIQ map we have set a foundation for future investigations and for any study addressing scientific questions on the interrelated aspects of the sea. In addition, in view of new and maybe still unpredicted uses of the sea, the METIQ map is a required document for the achievement of primary societal needs, connected with geohazard, georesources, pollution, energy, climate change.
Mapping the Quaternary in the Tyrrhenian Sea: a renewed “exploration” and its scientific and applied significance
Distefano Salvatore;
2023-01-01
Abstract
Within the framework of the METIQ project, our unit mapped the deepest parts of the Northern and Southwestern Tyrrhenian Sea, and the Eastern Sardinian and North-eastern Sicilian margins. Quaternary elements develop in extremely different physiography settings, which are the response to deep processes occurring in different geodynamic and tectonic contexts, from active to passive margins, from deforming and quiescent rifts, to ocean-like back-arc basins. Large areas of the external continental shelf lack any Holocene deposit, and thus a series of submerged coastal systems record the pace and the outcomes of the last sea-level transgression. Canyons span a range of morphologies, which illustrate general rules for their evolution, from inception and erosion to infill and deposition. At the base of slope, canyons often join leveed-channels, whose planform and architecture varies depending mainly on the tectonic history of the margins. Both canyons and channels have internal elements related to the processes of sediment feeding and routing to the deep-sea. Fans have different dimensions, shape and relative importance of smaller morphologic constituents. Landslides are a major feature in all the sectors of the mapped area. Mapping has shown the variety of sediment collapses mechanisms, comprehensive of the complete removal of thin, surficial extensive layers, glacial-like, slow downslope movements, and large margin collapses with multiple failure episodes. Pockmark fields are present in many of the seamounts of the northern Tyrrhenian Sea and on the continental slope of Sardinia and Sicily. Their distribution is sometimes controlled by active tectonics, while in others, a possible relationship with the distribution of surficial sedimentary units is apparent. Particularly in the Northern Tyrrhenian area, contour currents shape some portions of the continental slope and the infill of intraslope basins; moreover, they appear to influence the degree of sedimentary cover on seamount top. A reappraisal of Quaternary and active tectonics shows various belts indicating a recent spatial focussing of extensional tectonics within the extended Tyrrhenian Sea. Various new volcanic buildings have been highlighted, particularly in the Sardinia margin and in the northern Tyrrhenian Sea, contributing to the enlargement of the extent of the magmatic provinces of the Tyrrhenian-Apenninic region. In general, our mapping stands out as a reminder of the importance of a basic description and understanding of the physical character of the submarine territory. Our results indicate that, with the METIQ map we have set a foundation for future investigations and for any study addressing scientific questions on the interrelated aspects of the sea. In addition, in view of new and maybe still unpredicted uses of the sea, the METIQ map is a required document for the achievement of primary societal needs, connected with geohazard, georesources, pollution, energy, climate change.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
