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Angelo Camerlenghi, ICREA c/o Universitat de Barcelona (Spain)
David Amblas , GRC Geocičncies Marines, University of Barcelona (Spain)
Isabel Cacho, GRC Geocičncies Marines, University of Barcelona (Spain)
Toni Calafat , GRC Geocičncies Marines, University of Barcelona (Spain)
Miquel Canals , GRC Geocičncies Marines, University of Barcelona (Spain)
Jose Luis Casamor , GRC Geocičncies Marines, University of Barcelona (Spain)
Sergio Costa , GRC Geocičncies Marines, University of Barcelona (Spain)
Ben De Mol , GRC Geocičncies Marines, University of Barcelona (Spain)
Jaume Frigola , GRC Geocičncies Marines, University of Barcelona (Spain)
Olaia Iglesias , GRC Geocičncies Marines, University of Barcelona (Spain)
Sara Lafuerza, GRC Geocičncies Marines, University of Barcelona (Spain)
Galderic Lastras, GRC Geocičncies Marines, University of Barcelona (Spain)
Caroline Lavoie , GRC Geocičncies Marines, University of Barcelona (Spain)
Camino Liquete , GRC Geocičncies Marines, University of Barcelona (Spain)
Renata Giulia Lucchi , GRC Geocičncies Marines, University of Barcelona (Spain)
Mayte Pedrosa, GRC Geocičncies Marines, University of Barcelona (Spain)
Roger Urgeles , GRC Geocičncies Marines, University of Barcelona (Spain)
Joan Grimalt , CSIC Institute of Chemical and Environmental Research (Spain)
MŞ Ángeles Bárcena , University of Salamanca (Spain)
Elena Colmenero , University of Salamanca (Spain)
José Abel Flores, University of Salamanca (Spain)
Francisco Javier Sierro, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (Italy)
Andrea Caburlotto , Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (Italy)
Maurizio Grossi, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (Italy)
Rebesco Michele, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (Italy)
Monica Winsborrow, University of Tromsř (Norway)
Karin Andreassen, University of Tromsř (Norway)
Mienert Jürgen, University of Tromsř (Norway)
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We present the preliminary results of the BIO Hesperides Cruise SVAIS (August 2007) within IPY Activity N. 367 (Neogene ice streams and sedimentary processes on high- latitude continental margins - NICE STREAMS). We surveyed with multibeam echosounder and subbottom profiler 8600 km2 of seafloor mainly on the continental slope and outer shelf of the Southern Storfjiorden trough mouth fan. We also collected 518 km of seismic reflection profiles and 6 sediment cores.
On the continental slope we recognize a smooth W and NW part with upper slope gullies in correspondence of lobes of the continental shelf break, and a SE part affected by several shallow submarine landslides. Long straight channels develop down slope of the major slides.
Below an thin uppermost transparent seismic unit, often separated by a series of debris flow deposits with a characteristic lens shape, is a highly reflective parallel bedded unit, below which this is a less reflective unit on which submarine landslides has detached.
The deeper seismic units show that there is more then one level of gullies cut in buried debris flow units. These paleo gullies have a shape in cross section very similar to the modern ones. The profiles image more than one episode of mass movements. Below the depth of about 300 ms TWT there is no sign of sediment mass movement.
On the upper slope sediment cores contain bioturbated sediments overlaying a structureless debris-rich interval, which include sequences of silty-clay sediments interbedded with sandy-silt layers cyclically recurring at every 9-10 cm. This sequence overlay an interval of massive structureless debris. At the base of slope the sequence contains strongly bioturbated silty-clay sediments containing dispersed cm-thick bivalve's shells suggesting an oxygenated and nutrient rich environment. Initial micropalaentological analysis indicates that the sediments contain material deposited in a time interval that includes the Holocene and presumably the Deglaciation and some parts of the Last Glacial Period. Holocene sediments deposited within an oceanographic context similar to the present cover the top centimetres of the study area, while further downcore the sedimentation has occurred most likely on a glacial-like scenario, in where the proximity of ice-sheets and the extension of sea-ice cover played a major role in the oceanographic conditions and deposition processes.
The seafloor morphology of the outer shelf is dominated by icebergs scours. However, we were able to identify a large depositional lobe which appears to be the last major depositional event before ice retreat from the pouter continental shelf. This deposit is cut be a spectacular rectilinear grounded ice scour sided by smaller scale depositional ridges. Other minor scours and depositional lobes are visible in the surroundings. The depositional lobes are well imaged in shallow seismic data which permit the reconstruction of the relative age of the recent most deposits.
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