Description: The Plio–Pleistocene warm-temperate carbonate deposits along the SE coast of Rhodes (Greece) formed on a highly structured island ‘shelf’ during a major transgression-regression cycle, which reached bathyal depth during maximal transgression. The complex palaeobathymetry exhibits many characteristics of submarine canyons, especially of so-called ‘blind’ or ‘headless’ canyons — a canyon type, which is especially common in the modern Mediterranean. This study presents the palaeoenvironmental evolution of one of these canyons, which is today represented by the Lardos valley, eastern central Rhodes. The studied section comprises the middle Pleistocene (900–300 ka) and describes a shallowing-upward trend from bathyal to circalitoral depth. Thin fossiliferous debris flow layers document turnovers and abundance changes in fauna and floral of hard-bottom communities, which developed on the adjacent basement slopes and highs. The comparison of the obtained results with other studies from the southeastern coast of Rhodes suggests a high degree of diachroneity of lithological boundaries of these Plio–Pleistocene deposits, which can be best explained by progressive infill of small depocentres located at different altitude levels. Hence, lithological changes are interpreted to be time-transgressive from distal (low altitude) to proximal (high altitude) during transgression while time-transgressive from proximal to distal during regression. Consequently, the best chronostratigraphic correlation horizon is the surface of maximal transgression. The most probable age for this surface could be estimated at 1.1 to 0.8 Ma, 0.2–0.5 Ma younger than previous estimates. Furthermore, the current lithostratigraphic schemes for the Plio–Pleistocene deposits of southeastern Rhodes are reviewed and revised. Highlights ► The studied outcrop documents the uplift of Rhodes during the middle Pleistocene. ► The Plio–Pleistocene stratigraphy of Rhodes is reviewed and revised. ► The studied sedimentary unit is interpreted as submarine canyon deposit. ► Diachroneity of canyon deposits is most likely due to different altitudes of small depocentres.

Description: Sediment subbottom profiler and multi-beam data reveal that sediment drifts evolved in various depth intervals between 420 and 650 m water depth in the eastern Golf of Mexico and its gateways. Drift evolution on the western flank of the Yucatan Strait is controlled by the northbound Loop Current down to 800 m and by a countercurrent beneath. On the northern Campeche Bank and the West Florida Slope, drifts evolved in depth of 520–600 m and 420–550 m, respectively. In both instances, the causative contour current represents a counter flow to the Loop Current. The varying depth ranges correlate with an eastward rise of the upper boundary of the Antarctic Intermediate Water. The geometry and reflection pattern of upper slope deposits strongly suggest that the causative bottom current velocities in the eastern Gulf of Mexico varied significantly in space and time. The subbottom profiler data further show peculiar stacked diffraction hyperbolae in depths between 480 and 600 m. Camera and video observations from the seafloor off western Florida imply that the diffraction hyperbolas are formed by boulders and cliffs of sedimentary rock, which are locally colonized by coldwater corals, such as Lophelia pertusa, octocorals and stylasterids.

Description: Highlights: • Cold-water coral mound formation is mainly influenced by the baffling of fine grained material within a coral framework. • Mass wasting appears to be an important mound progradation process. • Even heavily reworked sediments contain valuable information on the original mound aggradation processes. Abstract: An unconformity-bound glacial sequence (135 cm thick) of a coral-bearing sediment core collected from the flank of a cold-water coral mound in the Banda Mound Province off Mauritania was analysed. In order to study the relation between coral framework growth and its filling by hemipelagic sediments, U-series dates obtained from the cold-water coral species Lophelia pertusa were compared to 14C dates of planktonic foraminifera of the surrounding matrix sediments. The coral ages, ranging from 45.1 to 32.3 ka BP, exhibit no clear depositional trend, while on the other hand the 14C dates of the matrix sediment provide ages within a much narrower time window of 〈3000 yrs (34.6–31.8 cal ka BP), corresponding to the latest phase of the coral growth period. In addition, high-resolution computer tomography data revealed a subdivision of the investigated sediment package into three distinct parts, defined by the portion and fragmentation of corals and associated macrofauna as well as in the density of the matrix sediments. Grain size spectra obtained on the matrix sediments show a homogeneous pattern throughout the core sediment package, with minor variations. These features are interpreted as indicators of redeposition. Based on the observed structures and the dating results, the sediments were interpreted as deposits of a mass wasting event, namely a debris flow. During this event, the sediment unit must have been entirely mixed; resulting in averaging of the foraminifera ages from the whole unit and giving randomly distributed coral ages. In this context, for the first time mass wasting is proposed to be a substantial process of mound progradation by exporting material from the mound top to the flanks. Hence, it may not only be an erosional feature but also widening the base of the mound, thus allowing further vertical mound growth.

Description: Here we provide a detailed qualitative and quantitative insight on recent sediment composition and facies distribution of a cold-water coral (CWC) mound using the example of the Propeller Mound on the Irish continental margin (Hovland Mound Province, Porcupine Seabight). Five facies types on Propeller Mound are defined: (1) living coral framework, (2) coral rubble, (3) dropstone, (4) hardground, representing the on-mound facies, and (5) hemipelagic sediment facies, which describes the off-mound area. This facies definition is based on already published video-data recorded by Remotely Operated Vehicle (ROV), photo-data of gravity cores, box cores, and dredges from sediment surfaces as well as on the composition of the sediment fraction coarser than 125 μm, which has been analyzed on five selected box cores. Sediment compositions of the living coral framework and coral rubble facies are rather similar. Both sediment types are mainly produced by corals (34 and 35 wt%, respectively), planktonic foraminifers (22 and 29 wt%, respectively), benthic foraminifers (both 7 wt%), and molluscs (21 and 10 wt%, respectively), whereas the living coral framework characteristically features additional brachiopods (6 wt%). Hardgrounds are well-lithified coral rudstones rich in coral fragments (〉30 surf%), foraminifers, echinoderms, and bivalves. The dropstone facies and the hemipelagic sediment typically carry high amounts of lithoclasts (36 and 53 wt%, respectively) and planktonic foraminifers (35 and 32 wt%, respectively); however, their faunal diversity is low compared with the coral-dominated facies (12 and 〈2 wt% coral fragments, 7 and 6 wt% benthic foraminifers, and 4 and 0 wt% balanids). Using the maximum likelihood algorithm within ArcGIS 9.2, spatial prediction maps of the previously described mound facies are calculated over Propeller Mound and are based on mound morphology parameters, ground-truthed with the sedimentary and faunal information from box cores, photographs, and video-data. This method is tested for the first time for CWC ecosystems and provides areal estimates of the predicted facies, as well as suggests further occurrences of living coral frameworks, coral rubble, and dropstones, which are not discovered in the area yet. Thus, sediment composition analysis combined with facies prediction mapping might provide a potential new tool to estimate living CWC occurrences and sediment/facies distributions on CWC mounds, which is an important prerequisite for budget calculations and definition of marine protected areas, and which will improve our understanding of CWC mound formation.

Description: Through the interplay of a stabilising cold-water coral framework and a dynamic sedimentary environment, cold-water coral carbonate mounds create distinctive centres of bio-geological accumulation in often complex (continental margin) settings. The IODP Expedition 307 drilling of the Challenger Mound (eastern Porcupine Seabight; NE Atlantic) not only retrieved the first complete developmental history of a coral carbonate mound, it also exposed a unique, Early-Pleistocene sedimentary sequence of exceptional resolution along the mid-latitudinal NE Atlantic margin. In this study, a comprehensive assessment of the Challenger Mound as an archive of Quaternary palaeo-environmental change and long-term coral carbonate mound development is presented. New and existing environmental proxy records, including clay mineralogy, planktonic foraminifer and calcareous nannofossil biostratigraphy and assemblage counts, planktonic foraminifer oxygen isotopes and siliciclastic particle-size, are thereby discussed within a refined chronostratigraphic and climatic context. Overall, the development of the ChallengerMound shows a strong affinity to the Plio-Pleistocene evolution of the Northern Hemisphere climate system, albeit not being completely in phase with it. The two major oceanographic and climatic transitions of the Plio-Pleistocene e the Late Pliocene/Early Pleistocene intensification of continental ice-sheet development and the mid-Pleistocene transition to the more extremely variable and more extensively glaciated late Quaternary e mark twomajor thresholds in Challenger Mound development: its Late Pliocene (〉2.74 Ma) origin and itsMiddleeLate Pleistocene to recent decline. Distinct surface-water perturbations (i.e. water-mass/polar front migrations, productivity changes, melt-water pulses) are identified throughout the sequence, which can be linked to the intensity and extent of ice development on the nearby BritisheIrish Isles since the earliest Pleistocene. Glaciation-induced shifts in surfacewater primary productivity are thereby proposed to fundamentally control cold-water coral growth, which in turn influences on-mound sediment accumulation and, hence, coral carbonate mound development throughout the Pleistocene. As local factors, such as proximal ice-sheet dynamics and on-mound changes in cold-water coral density, significantly affected the development of the Challenger Mound, they can potentially explain the nature of its palaeo-record and its offsets with the periodicities of global climate variability. On the other hand, owing to this unique setting, a regionally exceptional, high-resolution palaeo-record of Early Pleistocene (ca 2.6 to 2.1 Ma) environmental change (including early BritisheIrish ice-sheet development), broadly in phase with the 41 ka-paced global climate system, is preserved in the lower Challenger Mound. All in all, the Challenger Mound record highlights the wider relevance of coral carbonate mound archives and their potential to capture unique records from dynamic (continental margin) environments.