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  • During the Antarctic summer 1988-89, a geophysical survey (seismic, gravity and magnetics) was carried out by the National Institute of Oceanography and Applied Geophysics - OGS of Trieste, Italy, in the Ross Sea with the Research Vessel O.G.S. Explora. 23 lines of total length 4113.1 Km were collected. The cruise began on December 10,1988 from the harbor of Hobart (Australia) and ended on January 15, 1989, with its arrival in Dunedin (New Zealand). Gravimetric and geomagnetic data were continuously acquired during the cruise, with minor interruptions due to adverse sea conditions. The multichannel seismic survey was run in the Ross Sea from December 18 to January 8. The project has been financially supported by the Italian Antarctic Program (PNRA).

  • Complementary with the ODYSSEA project funded by PNRA, ANTSSS aimed at finding evidence for Late Pleistocene sedimentary signatures of major changes in the extent of grounded, marine based ice sheets in the Ross Sea, as preserved in slope/ rise drift deposits by means of seismic and oceanographic data. During the 2017 expedition, OGS Explora collected over 450 km of Single Channel Seismics (SCS), 1575 km2 of bathymetry, >500 km of sub-bottom, and oceanographic data, including Conductivity Temperature Depth (CTD), Acoustic Doppler Current Profiler (ADCP), Lowered-ADCP, Expendable Bathythermograph (XBT) and turbidity data. Part of the seismic data have been initially published in Gales et al. (2021) Role of dense shelf water in the development of Antarctic submarine canyon morphology. Geomorphology, 372, art. no. 107453. DOI: 10.1016/j.geomorph.2020.107453

  • During Austral Summer 1989-90, the National Institute of Oceanography and Applied Geophysics - OGS, conducted marine geological and geophysical surveys off South Pacific ocean, in the Weddell Sea over Bellingshausen Sea, in the Ross Sea and over Admundsen Sea. This cruise collected approximately 8763 km of multichannel seismic reflection (MCS) data. The surveys extended, in diferent area, between longitudes 34 and 172 degrees west , and between latitudes 59 and 76 degrees south. The surveys were carried out by the research vessel OGS Explora. The digital MCS data were recorded on a SERCEL SN 358 DMX system. The source consisted of an airgun array with variable configuration from a total volume of 45.16 litres fired approximately every 50 meters. A GPS + TRANSIT satellite receiver system was used for navigation. Processing of the data generally followed a conventional sequence: Reformat, Trace-sum with differential NMO, Quality control, Amplitude recovery, Deconvolution, Velocity analysis, NMO corrections, Mute, Trace weighting, Stack, Mixing, Filter, Balance.

  • This project was performed to investigate the evolution of Western ice sheet (WIS) in the Eastern Basin (Ross Sea), Antarctica. The Ross Sea is part of the West Antarctic Rift System that has three main depocenters as the Eastern Basin, the Central Basin and the Victoria Land Basin. The Eastern Basin contains a thick sedimentary sequence that tells about the WIS advance and retreat. DSDP cores were drilled in this area (Hayes and Frakes, 1975) gives knowledge about the stratigraphy and the depositional environment of the area from Upper Miocene to Pleistocene (Hayes and Frakes, 1975). Large erosional hiatuses and poor interpretations of DSDP cores, do not let to construct of the Eastern Basin depositional history and the evolution of the WIS (Hayes and Frakes, 1975; Denton et al., 1991). On the other hand, multichannel seismic studies in the Ross Sea gives more knowledge about the sedimentary sequences and unconformities (ANTOSTRAT, 1995). These studies show that Lower Pliocene is identified by a marked erosion surface, called RSU2 (De Santis et al., 1995; Brancolini et al., 1997), and is correlated with a large hiatus in DSDP 273 which is dated from 10.5 to 4 ma (Savage and Ciesielski, 1983). Horizon RSU2 corresponds to a sharp change in the structure and lithology of sediments, which may be interpreted as a major increase of the glacial influence. Thus, it is clear that RSU2 identifies a major, unique event in the depositional history at the Ross Sea. The explanation of this event is today largely hypothetical, based on progressive climatic cooling occurred during Pliocene and the consequent grow of the Antarctic ice sheet. For setting up reliable paleo-climatic models, however, we have to define precisely the extension and features of the ice sheet: thus, we proposed to carry out a detailed geophysical study in a specific area of the Ross Sea, for reconstructing dimensions and dynamics of the Eastern ice sheet during Pliocene, a period of large changes at a global level, anda also the most debated one for the history of the Antarctic ice sheet.

  • During Austral Summer1990-91 the National Institute of Oceanography and Applied Geophysics - OGS conducted marine geological and geophysical surveys in the Ross Sea, over Weddel Sea and in the Balleny Zone of the MacQuarie Triple Junction. This cruise collected approximately 6036 km of multichannel seismic reflection (MCS) data. The surveys extended, in different areas, between longitudes 37 and 56 degrees west, and between latitudes 59 and 62 degrees south (Weddel Sea), between longitudes 171 east and 178 degrees west, and between latitudes 71 and 73 degrees south (Ross Sea), between longitudes 150 and 158 degrees east , and between latitudes 51 and 62 degrees south (Balleny). The surveys were carried out by the research vessel OGS Explora. The digital MCS data were recorded on a SERCEL SN 358 DMX system. The source consisted of an airgun array with variable configuration from a total volume of 45.16 litres fired approximately every 50 meters. A GPS + TRANSIT satellite receiver system was used for navigation. Processing of the data generally followed a conventional sequence: Reformat, Trace-sum with differential NMO, Quality control, Amplitude recovery, Deconvolution, Velocity analysis, NMO corrections, Mute, Trace weighting, Stack, Mixing, Filter, Balance.

  • During Austral Summer 1989-90, the National Institute of Oceanography and Applied Geophysics - OGS, conducted marine geological and geophysical surveys off South Pacific ocean, in the Weddell Sea over Bellingshausen Sea, in the Ross Sea and over Admundsen Sea. This cruise collected approximately 8763 km of multichannel seismic reflection (MCS) data. The surveys extended, in diferent area, between longitudes 34 and 172 degrees west , and between latitudes 59 and 76 degrees south. The surveys were carried out by the research vessel OGS Explora. The digital MCS data were recorded on a SERCEL SN 358 DMX system. The source consisted of an airgun array with variable configuration from a total volume of 45.16 litres fired approximately every 50 meters. A GPS + TRANSIT satellite receiver system was used for navigation. Processing of the data generally followed a conventional sequence: Reformat, Trace-sum with differential NMO, Quality control, Amplitude recovery, Deconvolution, Velocity analysis, NMO corrections, Mute, Trace weighting, Stack, Mixing, Filter, Balance.

  • This project was performed to investigate the evolution of Western ice sheet (WIS) in the Eastern Basin (Ross Sea), Antarctica. The Ross Sea is part of the West Antarctic Rift System that has three main depocenters as the Eastern Basin, the Central Basin and the Victoria Land Basin. The Eastern Basin contains a thick sedimentary sequence that tells about the WIS advance and retreat. DSDP cores were drilled in this area (Hayes and Frakes, 1975) gives knowledge about the stratigraphy and the depositional environment of the area from Upper Miocene to Pleistocene (Hayes and Frakes, 1975). Large erosional hiatuses and poor interpretations of DSDP cores, do not let to construct of the Eastern Basin depositional history and the evolution of the WIS (Hayes and Frakes, 1975; Denton et al., 1991). On the other hand, multichannel seismic studies in the Ross Sea gives more knowledge about the sedimentary sequences and unconformities (ANTOSTRAT, 1995). These studies show that Lower Pliocene is identified by a marked erosion surface, called RSU2 (De Santis et al., 1995; Brancolini et al., 1997), and is correlated with a large hiatus in DSDP 273 which is dated from 10.5 to 4 ma (Savage and Ciesielski, 1983). Horizon RSU2 corresponds to a sharp change in the structure and lithology of sediments, which may be interpreted as a major increase of the glacial influence. Thus, it is clear that RSU2 identifies a major, unique event in the depositional history at the Ross Sea. The explanation of this event is today largely hypothetical, based on progressive climatic cooling occurred during Pliocene and the consequent grow of the Antarctic ice sheet. For setting up reliable paleo-climatic models, however, we have to define precisely the extension and features of the ice sheet: thus, we proposed to carry out a detailed geophysical study in a specific area of the Ross Sea, for reconstructing dimensions and dynamics of the Eastern ice sheet during Pliocene, a period of large changes at a global level, anda also the most debated one for the history of the Antarctic ice sheet.

  • Complementary with the ODYSSEA project funded by PNRA, ANTSSS aimed at finding evidence for Late Pleistocene sedimentary signatures of major changes in the extent of grounded, marine based ice sheets in the Ross Sea, as preserved in slope/ rise drift deposits by means of seismic and oceanographic data. During the 2017 expedition, OGS Explora collected over 450 km of Single Channel Seismics (SCS), 1575 km2 of bathymetry, >500 km of sub-bottom, and oceanographic data, including Conductivity Temperature Depth (CTD), Acoustic Doppler Current Profiler (ADCP), Lowered-ADCP, Expendable Bathythermograph (XBT) and turbidity data. Part of the seismic data have been initially published in Gales et al. (2021) Role of dense shelf water in the development of Antarctic submarine canyon morphology. Geomorphology, 372, art. no. 107453. DOI: 10.1016/j.geomorph.2020.107453

  • During the Antarctic summer 1988-89, a geophysical survey (seismic, gravity and magnetics) was carried out by the National Institute of Oceanography and Applied Geophysics - OGS of Trieste, Italy, in the Ross Sea with the Research Vessel O.G.S. Explora. 23 lines of total length 4113.1 Km were collected. The cruise began on December 10,1988 from the harbor of Hobart (Australia) and ended on January 15, 1989, with its arrival in Dunedin (New Zealand). Gravimetric and geomagnetic data were continuously acquired during the cruise, with minor interruptions due to adverse sea conditions. The multichannel seismic survey was run in the Ross Sea from December 18 to January 8. The project has been financially supported by the Italian Antarctic Program (PNRA).

  • Complementary with the ANTSSS project funded by EUROFLEETS, ODYSSEA aimed at investigating the sediment drifts to the west of the Hillary Canyon (Ross Sea continental margin) by means of seismic and oceanographic data to contribute to the understanding of past and present ocean dynamics and glacial history of this Antarctic sector. During the 32nd PNRA expedition, OGS Explora collected over 240 km of Single Channel Seismics (SCS), 2700 km2 of bathymetry, 500 km of sub-bottom, 6 gravity cores for a total of nearly 30 m of sediments, 4 box cores, 25 XBT launches, 2 rosette casts with water sampling, CTD, L-ADCP, turbidity and florescence probes. Part of the seismic data have been initially published in Conte R et al (2021) Bottom current control on sediment deposition between the Iselin Bank and the Hillary Canyon (Antarctica) since the late Miocene: An integrated seismic-oceanographic approach. Deep-Sea Research Part I: Oceanographic Research Papers 176, art. no. 103606, DOI: 10.1016/j.dsr.2021.103606