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During the Late Pleistocene Holocene, the Ross Sea Ice Shelf exhibited strong spatial variability in relation to the atmospheric and oceanographic climatic variations. Despite being thoroughly investigated, the timing of the ice sheet retreat from the outer continental shelf since the Last Glacial Maximum (LGM) still remains controversial, mainly due to a lack of sediment cores with a robust chronostratigraphy. For this reason, the recent recovery of sediments containing a continuous occurrence of calcareous foraminifera provides the important opportunity to create a reliable age model and document the early deglacial phase in particular. Here we present a multiproxy study from a sediment core collected at the Hallett Ridge (1800 m of depth), where significant occurrences of calcareous planktonic and benthic foraminifera allow us to document the first evidence of the deglaciation after the LGM at about 20.2 ka. Our results suggest that the co-occurrence of large Neogloboquadrina pachyderma tests and abundant juvenile forms reflects the beginning of open-water conditions and coverage of seasonal sea ice. Our multiproxy approach based on diatoms, silicoflagellates, carbon and oxygen stable isotopes on N. pachyderma, sediment texture, and geochemistry indicates that abrupt warming occurred at approximately 17.8 ka, followed by a period of increasing biological productivity. During the Holocene, the exclusive dominance of agglutinated benthic foraminifera suggests that dissolution was the main controlling factor on calcareous test accumulation and preservation. Diatoms and silicoflagellates show that ocean conditions were variable during the middle Holocene and the beginning of the Neoglacial period at around 4 ka. In the Neoglacial, an increase in sand content testifies to a strengthening of bottom-water currents, supported by an increase in the abundance of the tycopelagic fossil diatom Paralia sulcata transported from the coastal regions, while an increase in ice-raf

The continental margin is a key area for studying the sedimentary processes related to the advance and retreat of the Ross Ice Shelf (Antarctica); nevertheless, much remains to be investigated. The aim of this study is to increase the knowledge of the last glacial/deglacial dynamics in the Central Basin slope-basin system using a multidisciplinary approach, including integrated sedimentological, micropaleontological and tephrochronological information. The analyses carried out on three box cores highlighted sedimentary sequences characterised by tree stratigraphic units. Collected sediments represent a time interval from 24 ka Before Present (BP) to the present time. Grain size clustering and data on the sortable silt component, together with diatom, silicoflagellate and foraminifera assemblages indicate the influence of the ice shelf calving zone (Unit 1, 24-17 ka BP), progressive receding due to Circumpolar Deep Water inflow (Unit 2, 17-10.2 ka BP) and (Unit 3, 10.2 ka BP-present) the establishment of seasonal sea ice with a strengthening of bottom currents. The dominant and persistent process is a sedimentation controlled by contour currents, which tend to modulate intensity in time and space. A primary volcanic ash layer dated back at around 22 ka BP is correlated with the explosive activity of Mount Rittmann.

Highlights • We examine interplay between historical seismicity, mass failures and turbidites during sapropel S1 deposition; • We reconstruct chronology of earthquake triggered turbidites in the Ionian Sea during sapropel depostion; • We reconstruct the age of sapropel S1 in our core (6.0-10.2 kyr cal. BP) through Oxcal age modeling; • Turbidite emplacement time was deduced through age modeling. • We compiled a catalogue of mass flow events during several earthquake cycles. Abstract The recurrence of mass-flow units within sapropel S1, an organic carbon-rich lower Holocene marker bed in the Eastern Mediterranean Sea, was used to study the interplay between earthquakes and sedimentation along the seismically active Calabrian Arc (Ionian Sea). Nine turbidite beds interrupt anoxic conditions during the deposition of sapropel S1. Each of these turbidites is associated with sharp grain size and geochemical elemental anomalies (high Al and Si, low Ca and coarse-grained basal part marked by Zr peaks), and with displaced foraminiferal species from different bathymetric ranges. We used these proxies to identify turbidite beds also above and below the sapropel, where turbidite signature is less clear due to the absence of major color changes. Turbidite structure and composition, as well as comparison with historical seismoturbidites, suggest a seismic triggering for such mass flow events. The peculiar color, well-known composition, geochemistry and age of sapropel S1, make this unit a key bed within which turbidites may be considered a sort of sedimentary “bar code” recording high-energy events within the background pelagic sedimentation; deciphering this code will reconstruct paleo-seismicity in this well-defined stratigraphic interval. The pelagic units bracketing turbidite beds were radiometrically dated, and the age of the sapropel S1, deduced through age modeling, is between 6.0 and 10.2 kyr cal BP. The emplacement age of each turbidite was estimated considering the aver

Highlights • We examine interplay between historical seismicity, mass failures and turbidites during sapropel S1 deposition; • We reconstruct chronology of earthquake triggered turbidites in the Ionian Sea during sapropel depostion; • We reconstruct the age of sapropel S1 in our core (6.0-10.2 kyr cal. BP) through Oxcal age modeling; • Turbidite emplacement time was deduced through age modeling. • We compiled a catalogue of mass flow events during several earthquake cycles. Abstract The recurrence of mass-flow units within sapropel S1, an organic carbon-rich lower Holocene marker bed in the Eastern Mediterranean Sea, was used to study the interplay between earthquakes and sedimentation along the seismically active Calabrian Arc (Ionian Sea). Nine turbidite beds interrupt anoxic conditions during the deposition of sapropel S1. Each of these turbidites is associated with sharp grain size and geochemical elemental anomalies (high Al and Si, low Ca and coarse-grained basal part marked by Zr peaks), and with displaced foraminiferal species from different bathymetric ranges. We used these proxies to identify turbidite beds also above and below the sapropel, where turbidite signature is less clear due to the absence of major color changes. Turbidite structure and composition, as well as comparison with historical seismoturbidites, suggest a seismic triggering for such mass flow events. The peculiar color, well-known composition, geochemistry and age of sapropel S1, make this unit a key bed within which turbidites may be considered a sort of sedimentary “bar code” recording high-energy events within the background pelagic sedimentation; deciphering this code will reconstruct paleo-seismicity in this well-defined stratigraphic interval. The pelagic units bracketing turbidite beds were radiometrically dated, and the age of the sapropel S1, deduced through age modeling, is between 6.0 and 10.2 kyr cal BP. The emplacement age of each turbidite was estimated considering the aver

The ROSSLOPE is an Italian Antarctic project approved in the framework of the PNRA. The investigation of the interactions among marine currents, sea floor morphology, sediment texture and benthic communities is crucial to understand the dynamics of depositional and erosive processes on present-day seafloor, and represents an important key to study the paleo-environmental variation of the southern antarctic and subantarctic areas. This project aims to investigate the relation between present and past water mass circulation from modern and late-Cenozoic sedimentary sequences of the Ross Sea outer shelf and continental slope of the area of Adare and Central Basins, and the area to the east of Pennell-Iselin Banks. The study will be performed through the comparison and integration of data concerning the circulation of the present dense, cold water masses produced in the Ross Sea (HSSW e ISW), with 1) measurements of physical-chemical-biotic characteristics of surface sediments (water-sediment interface) and within the top 5 meters beneath the seafloor, 2) the geo-morphological features of these areas, 3) benthic acoustic facies typically related both to bottomcurrent activity (i.e. sediment drifts) and to down-slope mass processes within the stratigraphic section. In these areas few and scattered geological, geophysical, oceanographic and morpho-bathymetric data exist. We propose to study these existing data. The data base is constituted of previous data of: 1) multibeam surveys collected during PNRA and USA geophysical cruises 2) single-channel and multichannel Italian and foreign seismic data available by the Seismic Data Library System 3) PNRA sediment box cores and cores of which most already studied for other purposes and others yet to be studied. Moreover new morpho-bathymetric and sub-bottom acoustic data together with cores and box cores will be collected. All results will be compared in a multidisciplinary way with oceanographic knowledge to provide a depositio

The ROSSLOPE is an Italian Antarctic project approved in the framework of the PNRA. The investigation of the interactions among marine currents, sea floor morphology, sediment texture and benthic communities is crucial to understand the dynamics of depositional and erosive processes on present-day seafloor, and represents an important key to study the paleo-environmental variation of the southern antarctic and subantarctic areas. This project aims to investigate the relation between present and past water mass circulation from modern and late-Cenozoic sedimentary sequences of the Ross Sea outer shelf and continental slope of the area of Adare and Central Basins, and the area to the east of Pennell-Iselin Banks. The study will be performed through the comparison and integration of data concerning the circulation of the present dense, cold water masses produced in the Ross Sea (HSSW e ISW), with 1) measurements of physical-chemical-biotic characteristics of surface sediments (water-sediment interface) and within the top 5 meters beneath the seafloor, 2) the geo-morphological features of these areas, 3) benthic acoustic facies typically related both to bottomcurrent activity (i.e. sediment drifts) and to down-slope mass processes within the stratigraphic section. In these areas few and scattered geological, geophysical, oceanographic and morpho-bathymetric data exist. We propose to study these existing data. The data base is constituted of previous data of: 1) multibeam surveys collected during PNRA and USA geophysical cruises 2) single-channel and multichannel Italian and foreign seismic data available by the Seismic Data Library System 3) PNRA sediment box cores and cores of which most already studied for other purposes and others yet to be studied. Moreover new morpho-bathymetric and sub-bottom acoustic data together with cores and box cores will be collected. All results will be compared in a multidisciplinary way with oceanographic knowledge to provide a depositio

Detailed study of the temporal and spatial patterns of planktonic foraminiferal assemblages was performed on seven eastern Mediterranean deep-sea cores to evaluate differences and similarities in their stratigraphic records during the Eemian sapropel S5 interval. Changes in the succession of planktonic assemblages are very similar in all investigated sapropel S5 sequences. Analyses carried out on the 63 and 150 mu m size fractions indicate that during this time interval, size does not significantly affect the stratigraphic patterns. Benthic assemblages were studied at three sites, where their succession of changes was concordant but locally different. In this framework, comparison of S5 sapropels layers from different areas of the eastern Mediterranean suggests that the onset of the dark colour does not occur in the same stratigraphic position at a regional scale, whereas the absence/drastic reduction of benthic foraminifera within sapropel intervals appears to be a "time equivalent" event and corresponds to the last local occurrence of Globorotalia inflata. (c) 2005 Elsevier B.V. All rights reserved.

A one-dimensional ecosystem numerical model is used to simulate the ecosystem changes that could have occurred in the open ocean areas of the Eastern Mediterranean Sea during the Climatic Optimum interval (9500-6000 B.P., Mercone et al. [Mercone, D., Thomson, J., Croudace, I.W., Siani, G., Pateme, M., Troelstra, S., 2000. Duration of S1, the most recent sapropel in the eastern Mediterranean Sea, as indicated by accelerator mass spectrometry radiocarbon and geochemical evidence. Paleoceanography 15, 336-347]). In this period the S1 sapropel was deposited. S1 is the most recent sapropel in the succession of organic carbon-rich layers intercalated in normal Neogene sedimentary sequences. Different theories have been invoked in order to explain the deposition of this peculiar layer. Our simulations seem to indicate that the modified thermohaline circulation, supplying oxygen only in the first 500 m of the water column, is responsible for the sapropel deposition when higher productivity is allowed in the euphotic zone. The model shows the importance in this process of bacteria that consume oxygen by decomposing the Particulate Organic Matter (POM) produced in the upper water column. The sinking velocity of POM partially regulates the timescale of the occurrence of anoxia at the bottom and in the whole water column, allowing the relatively rapid onset of sapropel deposition. (c) 2005 Elsevier B.V. All rights reserved.

Calcareous nannoplankton, diatoms and organic-walled dinoflagellate cysts from seven eastern Mediterranean sediment cores were investigated to clarify the climatic and paleoceanographic conditions that influenced the deposition of sapropel S5 during Marine Isotopic Stage 5e. Warming of surface waters during S5 deposition is indicated by the high abundance of the calcareous nannofossil "small" Gephyrocapsa group, the presence of the dinoflagellate species Spiniferites mirabilis, Spiniferites pachydermus, Lingulodinium machaerophorum and Polysphaeridium zoharyi, and the tropical-subtropical diatom Pseudosolenia calearavis, Chaetoceros resting spores, Rhizosolenids and Thalassionema group. Increased productivity accompanied S5 deposition as evidenced by a general decrease in abundance of calcareous nannofossil superficial species and a coeval increase of dinocysts and diatoms. The productivity increase is further supported by an increase of the deep dwelling calcareous nannofossil species Florisphaera profunda. Stratification of near-surface waters is recorded by the presence of the dinocyst species L. machaerophorum and P zoharyi together with the co-occurrence of the diatom Chaetoceros resting-spore group, Thalassionema frauenfieldii, and Thalassionema nitzschioides var. parva, which reflect transport of neritic waters off-shore, and by the presence of some freshwater and transport-related diatom taxa (Cyclotella, Diatomella and Diploneis). Gradual shoaling of the nutricline and a gradual weakening of water stratification at the end of S5 deposition is indicated by an increase in the deep dwelling calcareous nannoplankton species Gladiolithus flabellatus, which suggests a less-deep niche compared to the deeper dwelling F profunda. Time transgressive variations in the distribution of the calcareous nannofossil Emiliana huxleyi and changes in the abundances of Gephyrocapsa oceanica, small Gephyrocapsa, G. flabellatus, and of the dinocysts R zoharyi and L. machaerophoru