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CoNISMa L.R.U. – Department of Geological Sciences and Geotechnologies, University of Milano-Bicocca - Piazza della Scienza, 4 – 20126 MILANO, Italy
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- PublicationOpen AccessEnvironmental and Oceanographic Conditions at the Continental Margin of the Central Basin, Northwestern Ross Sea (Antarctica) Since the Last Glacial Maximum(2021)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ;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.307 34 - PublicationRestrictedShallow seep-related seafloor features along the Malta plateau (Sicily channel – Mediterranean Sea): Morphologies and geo-environmental control of their distribution(2009-11)
; ; ; ; ; ;Savini, A.; Dip. Scienze Geologiche e Geotecnologie, Universita` di Milano-Bicocca, P.za della Scienza 4, 20126 Milano, Italy ;Malinverno, E.; Dip. Scienze Geologiche e Geotecnologie, Universita` di Milano-Bicocca, P.za della Scienza 4, 20126 Milano, Italy ;Etiope, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Tessarolo, C.; Dip. Scienze Geologiche e Geotecnologie, Universita` di Milano-Bicocca, P.za della Scienza 4, 20126 Milano, Italy ;Corselli, C.; Dip. Scienze Geologiche e Geotecnologie, Universita` di Milano-Bicocca, P.za della Scienza 4, 20126 Milano, Italy; ; ; ; Between 140 and 170 m water depth, more than 100 small-scale domes and peculiar ridges were mapped a few miles offshore of south-eastern Sicily along the Malta plateau (eastern Mediterranean Sea), Swath bathymetric data along with a dense grid of side scan sonar and seismic profiles were acquired in an area extending over 100 km2. Gravity cores, water samples and video observations were also collected at selected sites. Mapped domes were found from 50 to 200 m wide and no more than 5 m high occurring on the seafloor, isolated or arranged in clusters. Ridges consisted of large tabular sub-elongated structures, elevated from 5 to 10 m from the surrounding seafloor, and had flat tops on which numerous closeset, small cones occurred, appearing in video observation as carbonate buildings strongly colonized by gorgonians. Characteristic acoustic signatures (i.e. blank areas and/or turbidity zones and enhanced reflections in seismic records), measured gas anomalies in seawater samples and detected plumes on echosounder profiles suggest that both the domes and ridges are influenced by active seeps. In addition, their spatial distribution reflected patterns of tectonic lineaments produced by the late Miocene to present-day geo-dynamic evolution of the Malta plateau, which is also an important hydrocarbon province. Results from gravity cores suggest that mud extrusion seems to be the main process responsible for the origin of the domes, which are formed by gray mud with only a few centimeters of biogenic sand at the top, indicating that recent bioclastic material is not a major contributor to mound building. However, at present, active degassing appears to be the main process that controls the morphological and sedimentological expression of both the domes and ridges. Therefore, a quiescent or intermittent active stage for mud extrusion is considered.274 48 - PublicationOpen AccessParticle fluxes in the deep Eastern Mediterranean basins: the role of ocean vertical velocities(2009)
; ; ; ; ; ; ; ;Patara, L.; Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC) Viale Aldo Moro, 44, 40127 Bologna ;Pinardi, N.; Laboratorio SINCEM, Università di Bologna, Via San Alberto 163, 48100 Ravenna ;Corselli, C.; Dipartimento di Scienze Geologiche e Geotecnologie, Universit`a Milano-Bicocca, Piazza della Scienza 4, 20126 Milan, Italy ;Malinverno, E.; Dipartimento di Scienze Geologiche e Geotecnologie, Universit`a Milano-Bicocca, Piazza della Scienza 4, 20126 Milan, Italy ;Tonani, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia ;Santoleri, R.; Istituto di Scienze dell’Atmosfera e del Clima – C.N.R., Via del Fosso del Cavaliere 100, 00133 Rome, Italy ;Masina, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; ; ; ; ; ; This paper analyzes the relationship between deep sedimentary fluxes and ocean current vertical velocities in an offshore area of the Ionian Sea, the deepest basin of the Eastern Mediterranean Sea. Sediment trap data are collected at 500m and 2800m depth in two successive moorings covering the period September 1999–May 2001. A tight coupling is observed between the upper and deep traps and the estimated particle sinking rates are more than 200mday−1. The current vertical velocity field is computed from a 1/16 ×1/16 Ocean General Circulation Model simulation and from the wind stress curl. Current vertical velocities are larger and more variable than Ekman vertical velocities, yet the general patterns are alike. Current vertical velocities are generally smaller than 1mday−1: we therefore exclude a direct effect of downward velocities in determining high sedimentation rates. However we find that upward velocities in the subsurface layers of the water column are positively correlated with deep particle fluxes. We thus hypothesize that upwelling would produce an increase in upper ocean nutrient levels – thus stimulating primary production and grazing – a few weeks before an enhanced vertical flux is found in the sediment traps. High particle sedimentation rates may be attained by means of rapidly sinking fecal pellets produced by gelatinous macro-zooplankton. Other sedimentation mechanisms, such as dust deposition, are also considered in explaining large pulses of deep particle fluxes. The fast sinking rates estimated in this study might be an evi- Correspondence to: L. Patara (patara@bo.ingv.it) dence of the efficiency of the biological pump in sequestering organic carbon from the surface layers of the deep Eastern Mediterranean basins.196 119 - PublicationOpen AccessThe exploration of eastern Mediterranean deep hypersaline anoxic basins with MODUS: a significant example of technology spin-off from the Geostar Program(2006-03-20)
; ; ; ; ;Malinverno, E.; CoNISMa L.R.U. – Department of Geological Sciences and Geotechnologies, University of Milano-Bicocca - Piazza della Scienza, 4 – 20126 MILANO, Italy ;Gasparoni, F.; Tecnomare SpA - San Marco, 3584 – 30124 VENEZIA, Italy ;Gerber, H. W.; TFH Berlin, University of Applied Sciences - Luxemburger Str. 10 – D-13353 BERLIN, Germany ;Corselli, C.; CoNISMa L.R.U. – Department of Geological Sciences and Geotechnologies, University of Milano-Bicocca - Piazza della Scienza, 4 – 20126 MILANO, Italy; ; ; A significant example of technological spin-off from the GEOSTAR project is represented by the special-purpose instrumented module, based on the deep-sea ROV MODUS, which was developed in the framework of the EU-sponsored project BIODEEP. The goal to be achieved has been defined as the exploration, through real-time video images, measurements and accurate video-guided sampling, of the deep hypersaline anoxic basins of the eastern Mediterranean Sea at water depths well exceeding 3000 meters. Due to their peculiar characteristics, these basins are one of the most extreme environments on Earth and represent a site of utmost interest for their geochemical and microbial resources. The paper presents the strategies and the main results achieved during the two cruises carried out within the BIODEEP project.189 192