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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 ANGELINA (ANtarctic GEophysical Long range INternational Acquisition) programme was a seismic exploration cruise in the Adelaide Fracture Zone on the Pacific Margin, near Marguerite Bay and Adelaide Island; data were collected between longitude 68 and 74 degrees West, and latitude 66 and 69 degrees South. During this programme 610 km of 20-fold multichannel seismic reflection (MCS) data, 20 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 75 litres fired every 75 meters into a 3000 m cable consisting of 120 hydrophone groups towed at an average depth of 10 m. A GPS + TRANSIT satellite receiver system was used for navigation. The Chief Scientist on this programme was: Michele Pipan of the Dipartimento di Scienze Geologiche Ambientali e Marine of the Università di Trieste, via Weiss n.2, 34127 Trieste, Italy. Processing of the data generally followed a conventional sequence: Reformat, Quality control, Amplitude recovery, Deconvolution, Velocity analysis, NMO corrections, Mute, Stack, Mixing, Filter, and Dynamic trace equalisation.

  • 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 ANGELINA (ANtarctic GEophysical Long range INternational Acquisition) programme was a seismic exploration cruise in the Adelaide Fracture Zone on the Pacific Margin, near Marguerite Bay and Adelaide Island; data were collected between longitude 68 and 74 degrees West, and latitude 66 and 69 degrees South. During this programme 610 km of 20-fold multichannel seismic reflection (MCS) data, 20 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 75 litres fired every 75 meters into a 3000 m cable consisting of 120 hydrophone groups towed at an average depth of 10 m. A GPS + TRANSIT satellite receiver system was used for navigation. The Chief Scientist on this programme was: Michele Pipan of the Dipartimento di Scienze Geologiche Ambientali e Marine of the Università di Trieste, via Weiss n.2, 34127 Trieste, Italy. Processing of the data generally followed a conventional sequence: Reformat, Quality control, Amplitude recovery, Deconvolution, Velocity analysis, NMO corrections, Mute, Stack, Mixing, Filter, and Dynamic trace equalisation.

  • 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 ANGELINA (ANtarctic GEophysical Long range INternational Acquisition) programme was a seismic exploration cruise in the Adelaide Fracture Zone on the Pacific Margin, near Marguerite Bay and Adelaide Island; data were collected between longitude 68 and 74 degrees West, and latitude 66 and 69 degrees South. During this programme 610 km of 20-fold multichannel seismic reflection (MCS) data, 20 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 75 litres fired every 75 meters into a 3000 m cable consisting of 120 hydrophone groups towed at an average depth of 10 m. A GPS + TRANSIT satellite receiver system was used for navigation. The Chief Scientist on this programme was: Michele Pipan of the Dipartimento di Scienze Geologiche Ambientali e Marine of the Università di Trieste, via Weiss n.2, 34127 Trieste, Italy. Processing of the data generally followed a conventional sequence: Reformat, Quality control, Amplitude recovery, Deconvolution, Velocity analysis, NMO corrections, Mute, Stack, Mixing, Filter, and Dynamic trace equalisation.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.