Fig. 6

Interpretation of the migrated seismic lines BOOST 3 and 5. Line BOOST 3 (position in Fig. 2) crosses the north-easternmost and deepest part of the study area, along which can be recognized from NW to SE: a basinal area filled by a breakup sequence overlying a thinned and faulted transitional crust (COT) and covered by a thick drift sequence mainly consisting of contourite and turbidite deposits; the isolated faulted crustal block (CB) of continental nature (CC) covered by a sediment drift; the two prominent major and minor ridges consisting of seamounts interpreted as volcanic edifices. Possible buried magmatic intrusions were also identified. The marine magnetic profile AB (position in Fig. 2) acquired along the south-eastern part of the seismic line BOOST 3 is also reported below the line. Insets A and B respectively show the drag folds along the fault bounding the CB to the north-west and a young volcano that crosses two buried landslide bodies. Along the line BOOST 5 (position in Fig. 2) can be recognized: the southern and central part of the continental shelf, in which a V-shaped glacial trough is located; the continental slope, which consists of seaward glacial prograding sediments; the continental rise, which is divided into two basinal areas by the presence of the isolated faulted CB surrounded by transitional crust; the deepest and northernmost part of the line includes the same basinal area that was described along the line BOOST 3. It is inferred that the fault at the southeastern end of the CB (SF) along the line BOOST 3 may cross the central part of the basin between the CB and the continental slope visible along the line BOOST 5. This structure may have a significant strike-slip component of movement as an abrupt contact between sequences of different ages is visible across the fault, which could be also responsible for the indentation of the shelf-break (see Figs. 2 and 3A) characterized by a right-lateral displacement. Insets C shows the drag folds along the fault that bounds the CB to the north. Uninterpreted seismic profiles BOOST 3 and 5 are available in the Supplementary Material.