Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS
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High-resolution multichannel seismic profiles have been collected in January–March 2017 by OGS on the continental rise off the Sabrina Coast (East Antarctica). The data were acquired as part of the Italian Program of Antarctic Research (PNRA) TYTAN “Totten Glacier dynamics and Southern Ocean circulation impact on depositional processes since the Mid- to Late Cenozoic” project (PI: F. Donda-OGS) during the Australian Marine National Facility survey IN2017-V01 on board the RV Investigator. TYTAN was embedded in to the Australian project "Interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles” that aimed to understand the interaction of Totten Glacier and its ice drainage basin with the Southern Ocean during periods of warming and ice-sheet retreat in the Pleistocene and Holocene. In order to achieve these scientific objectives, three areas were identified for the geophysical and oceanographic survey: two on the continental slope and rise off Sabrina Coast and one on the continental shelf, which was not investigated because it remained covered by sea ice throughout the season. Expanded and well-preserved sedimentary successions imaged on the TYTAN seismic data highlight the potential of this region for deep ocean drilling, which will provide unprecedented history of the glaciers evolution in the Aurora Basin and their sensitivity to climate change under different background state conditions. In fact, TYTAN seismic data played a crucial role in the identification of potential drilling sites for the IODP 1002 Proposal “Totten Glacier Climate Vulnerability under varying Neogene climate conditions: Lessons for East Antarctic Ice Sheet climate sensitivity” (under review).
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During austral summer1994/95, the National Institute of Oceanography and Applied Geophysics - OGS, on board the research vessel OGS-Explora, conducted marine geological and geophysical surveys along the Antarctic Peninsula. The SANSCRITO (Seismic ANalysis SCotia RIdge Tectonic Outcome) programme was a seismic exploration cruise in the Scotia Sea to understand the tectonic history and evolution of the region; data were collected between longitude 45 and 54 degrees West, and latitude 59 and 65 degrees South. During this programme 1990 km of 30-fold multichannel seismic reflection (MCS) data, 14 second records, 4 ms sample rate, were recorded on a SERCEL SN 358 DMX system. The source consisted of an airgun array with a total volume of 80 litres fired every 50 meters into a 3000 m cable consisting of 120 hydrophone groups towed at an average depth of 12 m. A GPS + TRANSIT satellite receiver system was used for navigation. The Chief Scientist on this programme was: Emanuele Lodolo of the National Institute of Oceanography and Applied Geophysics - OGS, Borgo Grotta Gigante n. 42/C, 34010 Sgonico (Trieste), Italy. 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, and Dynamic trace equalisation.
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During Austral Summer1991-92 the National Institute of Oceanography and Applied Geophysics - OGS conducted marine geological and geophysical surveys over the Antarctic Peninsular and the Bransfield Strait. During this cruise approximately 3407 km of 30-fold multichannel seismic reflection (MCS) data were collected in the Antarctic Peninsular and the Bransfield Strait between longitudes 50 and 78 degrees West, and latitudes 60 and 68 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 a total volume of 71.96 litres fired approximately every 50 meters into a 3000 m cable consisting of 120 hydrophone groups towed at an average depth of 12 m. A GPS + TRANSIT satellite receiver system was used for the 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.
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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.
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During Austral Summer1991-92 the National Institute of Oceanography and Applied Geophysics - OGS conducted marine geological and geophysical surveys over the Antarctic Peninsular and the Bransfield Strait. During this cruise approximately 3407 km of 30-fold multichannel seismic reflection (MCS) data were collected in the Antarctic Peninsular and the Bransfield Strait between longitudes 50 and 78 degrees West, and latitudes 60 and 68 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 a total volume of 71.96 litres fired approximately every 50 meters into a 3000 m cable consisting of 120 hydrophone groups towed at an average depth of 12 m. A GPS + TRANSIT satellite receiver system was used for the 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.
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During austral summer1996/97 the National Institute of Oceanography and Applied Geophysics - OGS, on board the research vessel OGS-Explora, conducted marine geological and geophysical surveys along the Antarctic Peninsula. The SEDANO II (SEdiment Drifts of the ANtarctic Offshore) programme was the continuation of SEDANO I , acquired in 1995 (SDLS-47). This interdiciplinary programme included geology, geophysics and oceanography for the study of the sedimentary sequences of the continental rise of the Pacific Margin in the Antarctic Peninsula. During this programme 712 km of 60-fold multichannel seismic reflection (MCS) data, 8 second records, 2 ms sample rate and 286 km of single channel seismic reflection (SCS) data, 3 seconds, 1 ms sample rate, were recorded on a SERCEL SN 358 DMX system. The source consisted of an airgun array with a total volume of 60 litres, fired every 25 meters into a 3000 m cable consisting of 120 hydrophone groups towed at an average depth of 12 m for the MCS data. The SCS data were acquired every 12,5 meters into a 18 m cable consisting of 8 hydrophone groups towed at an average depth of 3 m, except line IT97AP242H acquired every 25 m, 8 seconds and 2 ms sample rate. A GPS + TRANSIT satellite receiver system was used for navigation. The Chief Scientists on this programme was: Angelo Camerlenghi of the National Institute of Oceanography and Applied Geophysics - OGS, Borgo Grotta Gigante n. 42/C, 34010 Sgonico (Trieste), Italy. Processing of the MCS data generally followed a conventional sequence: Reformat, Quality control, Amplitude recovery, Deconvolution, Velocity analysis, NMO corrections, Mute, Trace weighting, Stack, Mixing, Filter, Dynamic trace equalisation. The SCS data were processed using the following sequence: Reformat, Quality control, Deconvolution, Sum traces (from 8 to 1), Mute, Mixing, Filter, Dynamic trace equalisation.
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The main objective of EGLACOM is the geophysical and stratigraphic high-resolution study of an ice stream dominated marine depositional system of the Arctic margin in order to reconstruct the margin evolution locally from the Pliocene to the recent-most deglaciation, and to define the sedimentary architecture and seafloor morphology as it changed through time since the onset of glacial conditions. The target study area is the southern margin of Svalbard, and in particular the glacial sedimentary system fed by the ice stream once occupying the Storfjiorden glacial trough in the northern Barents Sea. 1071 kilometres of MultiChannel Seismic profiles have been acquired using Sleeve Airguns 96-channel Sercel digital streamer.
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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.
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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).
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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.
OGS Composite Data Center