Geohazard features of the Northern Sardinia

Figures & data

Figure 1. (A) Tectonic evolution of the central-western Mediterranean, from 20 to 7 Ma. The 10° and 23° CCW rotations of the Corso–Sardinian block is represented using as reference the fixed European block. Legend: (1) Alpine wedge; (2) pole for the Corsica–Sardinia rotation; (3) arc-related volcanics (e.g. Beccaluva et al., 1985; Lonergan & White, 1997; Serri et al., 1993 and references therein). The 20 Ma Corse–Sardinia position is inferred from Gattacceca (2001) (modified by Speranza et al., 2002). (B) Simplified sketch of the northern Sardinia margin showing the two main Oligocene–Miocene offshore basins and the associated faults (modified based on the work of Thomas & Gennesseaux, 1986). The draft of offshore Miocene volcanism from the south-western Corsica margin has been adapted from Rollet et al. (2002).

(A) shows 4 maps of the western Mediterranean, centered on the Sardinia and Corsica; each map represents the rotation of the Sardinia–Corse block during Oligocene and Miocene; parallel lines with triangle represent the Alpine wedge; the circle represents the pole for the Corsica–Sardinia rotation; and triangles represent the arc-related volcanics; whereas (B) highlights the study area; a satellite picture shows the emerged land and digital elevation model of submerged, highlighted the main faults on land and sea and the main morphological features discussed in the text.

Figure 2. Sections from seismic data: (A) Porto Torres Basin (B) Castelsardo Basin (C) Bonifacio Basin; legend: (1) normal (?) fault; (2) basement; (3) Oligocene–Miocene sedimentary and volcanic sequences; (4) Pliocene–Quaternary sequences (from Thomas & Gennesseaux, 1986, simplified).

Three interpreted sections from seismic reflection data and their geographic location show the structural and stratigraphic setting of the basins. (A) shows the section of Porto Torres basin; (B) shows the Castelsardo basin section; and (C) shows the Bonifacio basin section.

Figure 3. 3D blocks of the Digital Elevation Model (DEM), showing the main morphological features of Castelsardo Canyon; (A) main canyon talweg and a left-lateral tributary channel detached from the main canyon axis by a 300 m-high scarp; (B) meandering course of the canyon axis; and (C) examples of morphological reactivation within a tributary channel flowing into the canyon from the eastern side.

Three-dimensional blocks from the digital elevation model (DTM), showing the morphological features of the Castelsardo Canyon and its tributary channels, their location is shown in the inbox. The (A) block highlights the main canyon talweg and an abandoned tributary channel; the (B) block shows the deeply incised and meandered section of the canyon axis; and the (C) block shows the thalweg of the eastern tributary channel, with examples of morphological reactivation on both channel walls.

Figure 4. (A) Shaded relief from the DEM of the NE Sardinian continental margin. (B) 3D block of the Lavezzi canyon heads: (1) beach-rocks at 100 m depth; (2) edge of the prograding continental shelf; (3) retrogressive canyon head; (4) intracanal deposit from upslope failures; (5) erosional bedforms from channelized flows; and (6) retrogressive failure undermining the toe of former landslide deposits, perching within the channel axis.

Beccaluva, L., Gabbianelli, G., Lucchini, F., Rossi, P. L., & Savelli, C. (1985). Petrology and K/Ar ages of volcanics dredged from the Eolian seamounts: Implications for geodynamic evolution of the southern Tyrrhenian basin. Earth and Planetary Science Letters, 74(2-3), 187–208. https://doi.org/10.1016/0012-821X(85)90021-4

 Web of Science ®Google Scholar

Lonergan, L., & White, N. (1997). Origin of the Betic-Rif mountain belt. Tectonics, 16(3), 504–522. https://doi.org/10.1029/96TC03937

 Web of Science ®Google Scholar

Serri, G., Innocenti, F., & Manetti, P. (1993). Geochemical and petrological evidence of the subduction of delaminated Adriatic continental lithosphere in the genesis of the Neogene–quaternary magmatism of central Italy. Tectonophysics, 223(1-2), 117–147. https://doi.org/10.1016/0040-1951(93)90161-C

 Web of Science ®Google Scholar

Gattacceca, J. (2001). Cinématique du bassin liguro–provencal entre 30 et 12 Ma. Implications géodynamiques [PhD thesis]. Ecole des mines de Paris, 299 pp.

 Google Scholar

Speranza, F., Villa, I. M., Sagnotti, L., Florindo, F., Cosentino, D., Cipollari, P., & Mattei, M. (2002). Age of the Corsica–Sardinia rotation and Liguro–Provençal basin spreading: New paleomagnetic and Ar/Ar evidence. Tectonophysics, 347(4), 231–251. https://doi.org/10.1016/S0040-1951(02)00031-8

 Web of Science ®Google Scholar

Thomas, B., & Gennesseaux, M. (1986). A two-stage rifting in the basins of the Corsica-Sardinian straits. Marine Geology, 72(3-4), 225–239. https://doi.org/10.1016/0025-3227(86)90121-0

 Web of Science ®Google Scholar

Rollet, N., Déverchere, J., Beslier, M. O., Guennoc, P., Réhault, J. P., Sosson, M., & Truffert, C. (2002). Back arc extension, tectonic inheritance, and volcanism in the Ligurian Sea, Western Mediterranean. Tectonics, 21(3).

 Web of Science ®Google Scholar

Data Availability Statement

Data are available upon reasonable request by contacting the first authors at the mail address: [email protected], [email protected].