Abstract This paper synthesizes the geology of the Atlantic Margin off the coast of Iberia and surrounding Abyssal Plains using published thematic mapping freely downloadable from EMODNET-Geology portal at different scales. Selected information was chosen in order to highlight mineral occurrences and natural hazards overlaid on geological and morphological maps. Altogether, this information is published and interpreted here for the first time; nevertheless this exercise can be carried out by anyone interested and allows different visualizations of geological objects. Cross-correlations of geological objects and processes can easily arise. Because all of the information (each piece of data and metadata) in the EMODNET-Geology portal has bibliographic references associated, readers are able to find the original source of information. It is shown that clicking in and out of layers of information (that cannot be found all together in a single scientific paper) allows quick cross-correlation using the EMODNET Geology thematic portal. This allows a free, versatile and quick way of cross-correlating geological objects and processes in vast marine areas and their comparison with onshore geology.

Abstract Megabeds are thick sedimentary layers extending over thousands of square kilometres in deep-sea basins and are thought to result from large slope failures triggered by major external events. Such deposits have been found in at least three areas of the Mediterranean Sea. Although their discovery dates back to the early 1980s, many questions remain concerning their initiation, source area, extent and the nature of their emplacement. One of the largest previously documented megabeds was emplaced during the Last Glacial Maximum across the Balearic Abyssal Plain, with a thickness of 8–10 m in water depths of up to 2800 m. New 3.5 kHz sub-bottom profiles and sediment cores provide greater constraints on the lateral variability of the megabed and allow it to be mapped beyond previous estimates, with a revised areal extent of 90 000–100 000 km 2 . The megabed terminations show a gradual pinchout to the west and an abrupt eastward termination against the steep Sardinia margin. The megabed presents, in seismic profiles and sediment cores, a tripartite subdivision, which most likely corresponds to the changes in flow regimes across the basin, with a central area of sandy facies and an erosional base oriented NNE–SSW; this allows renewed discussions about the sources and triggers of the megabed.

Abstract Several canyons are observed along the Turkish margin of the western Black Sea that are associated with a prominent unconformity and interpreted to be the manifestations of the sea-level fall during the Messinian salinity crisis in the Mediterranean. In this study, their morphology, geometry and fill characteristics, as well as downslope evolution, are compared and contrasted using four 3D seismic surveys and some 2D regional seismic lines. Two types of canyon morphologies are observed in the study area: (1) shelf incising and (2) blind. Located in the western part of the study area and deeply incised into a wide shelf, the Karaburun Canyon extends roughly in a SW–NE direction. The fill of the canyon is almost absent on the shelf, where the canyon base is downlapped by a series of Pliocene clinoforms. A thin fill appears on the upper slope, which gets thicker towards the lower slope. The eastern part of the study area is dominated by a series of blind canyons (Boğaziçi canyons). They are typically confined to the continental rise, with their heads hardly reaching the lower slope. Their fill is entirely characterized by mass-transport complexes (MTCs). It is concluded that during the Messinian lowstand, the sediments within the Karaburun Canyon bypassed the wide shelf and were funnelled down to the continental rise and abyssal plain through the slope, which was followed by progradation of the basin margin during the relative sea-level rise in the Pliocene. A minimal imprint by tectonics in that particular area might have helped establish more stable conditions for the development of a relatively mature sediment dispersal system extending from the hinterland down to the basin centre. In this area, the shelf-slope morphology was dominantly shaped by the depositional geometries of the sedimentary packages. Being fully confined to the continental rise, the Boğaziçi canyons are situated in an area where shelf-slope morphology is governed by the Late Cretaceous volcanic arc. Parallel with the coastline, these volcanic edifices have created fairly steep dips; thus, leading to the development of an unstable basin margin and favouring MTC deposition at least since the Early–Middle Miocene. The width and relief of the canyons display a decreasing trend from west to east, which may be attributed to their relative distance from a possible drainage system in the vicinity of the Bosporus that might have acted as the major sediment supplier during this period.

Abstract An active exploration campaign in the Exmouth Plateau has yielded gas discoveries in a coeval wave-influenced delta and deep-water, sand-rich fan succession. Depositional elements were organized into clinoform seismic stratigraphic units that blanketed irregular topography created by extensional tectonics. Clinoform geometries revealed steady, rising and falling shelf-slope break trajectories. Slope successions associated with rising trajectories were devoid of deep-water feeder systems. In contrast, during steady to falling trajectories, the slope was characterized by numerous gullies. These gullies served as the main delivery system for sediment gravity flows into the basin. In some instances, an individual gully dominated and captured the flows of subordinate gullies and developed into a larger feeder system. The feeder systems were self-sourced and cannibalized the deltaic and slope successions through knickpoint retreat. Arcuate strandplains organized into wave-influenced cuspate lobes characterized the deltaic succession. Littoral drift was locally to the east. Delta front well information indicated excellent reservoir quality. Sedimentological analysis of core data indicated different depositional processes as a function of the clinoform geometries. High quality delta front sands were fed into the slope and basin floor as sediment gravity flows and deposited as coalescing sand-rich fans. The fan cores were composed of high-density turbidites that graded into debrites and linked debrites along the margins. The deep-water fans were of favorable to excellent reservoir quality.