EGLACOM Cruise July-august 2008 on the Storfjorden Fan: A Quasi Real-time Presentation Of Preliminary

Results

On board participants:M. Rebesco, F. Zgur, A. Caburlotto, C. De Vittor, L. Facchin, D. Deponte, C. Pelos, I. Tomini, R. De Vittor

Onshore participants: L. Petronio, M. Lipizer, P. Del Negro, A. Crise, G. Rossi, G. Madrussani, D. Praeg, S. Ceramicola, F. Donda, L. De Santis

Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS)

EGLACOM = Evolution of a GLacial Arctic COntinental Margin:

the southern Svalbard ice stream-dominated sedimentary system

International Polar Year 2007-2009:66 proposals submitted to CSNA in November 2006

1882-3: 11 nations, 14 research stations in the Polar Regions. 15 expeditions (12 Arctic, 3 Antarctic)

1932-3: 40 nations, 114 research stations across the Arctic.

1957-8: 61 nations, 45 research stations across the Antarctic and sub-Antarctic islands.

EGLACOM project belongs to the IPY Activity N. 367 (Neogene ice streams and sedimentary processes on high- latitude continental margins – NICE STREAMS).

EGLACOM cruise (08 July –04 August ‘08) was funded by OGS with funds provided by MIUR and derived from service for private companies

R/V OGS-Explora

Acknowledgments

We also acknowledge the logistic support given by the Data Acquisition and Technologic Development group (coordinated by Giorgio Gelsi), by the Seismic Data Processing group (coordinated by Nigel Wardell), by the Environmental Geophysics group (Diego Cotterle for the GIS database), by the Administrative Support group (coordinated by Mauro Jerman) and by the many other colleagues from OGS, including Daniela Accettella and Andrea Cova for the suggestions on the swath bathymetry data.

The realization of this cruise was made possible by the support of the Head of the RIMA Department (Riccardo Ramella), that we acknowledge. We wish to thank the captains Franco Sedmak and Carmine Teta and the crew of R/V OGS-Explora for their collaborative and effective assistance throughout the cruise.

SVAIS CruiseBio Hesperides, July-August

‘07

EGLACOM:Objectives:

1) Geophysical study of an ice stream-dominated marine depositional system of the Arctic margin (the Storfjiorden Fan) in order to reconstruct the margin evolution from the Pliocene.

2) Study of oceanographic processes connected to the Polar front by means of seismic oceanography methodologies.

5) Detailed analysis of sound velocity and of the variation of the wavelet close to the area of the EU HYDRATECH project.

6) Geological characterization of fluid flow systems in the area.

3) Study of the organic carbon cycle to estimate the efficiency of biological pumps in the sequestration and export of CO2.

Instruments:

Multibeam: Reson SeaBat 8111 (100 kHz); + SeaBat 8150 (12 kHz);

Echosounder: Simrad Kongsberg EA600 (18 kHz);

Sub-bottom profiler: Benthos CAP-6600 CHIRP II (2-7 kHz);

MultiChannel Seismics: 4 Sleeve Airguns (160 cubic inches) +

1200 m (96 channels) Sercel digital streamer;

ADCP (Acoustic Doppler Current Profiler): RDI Ocean surveyor (75 KHz);

Thermosalinograph: seabird SBE 21 with sea-water intake for sampling;

XBT (expendable bathythermograph): Sippican MK21;

CTD: SBE911plus + Carousel sampler: SBE32 with 12 10-litre Niskin bottles;

Gravity corer ( 183 cm pipe length).

Data in numbers

1,071 km of MultiChannel Seismic profiles

16,744 kmq of Multibeam bathymetry

4,079 km of SubBottom Profiles

>4,000 nm (>500 hours) of ADCP data

>4,000 nm of Thermosalinograph data

60 XBT launched

6 CTD casts

17 water samples in 3 casts

18 samplings of surface water

4 Gravity cores

Northern Storfjorden

Fan:debris flow

deposits

SE Storfjorden Fan: large slides

Kveithola Trough

Conclusions

1) occurrence of slides in the Storfjorden Fan is not evenly distributed in space and time (only debris flow deposits in the north; large slides in the south; no visible slides beneath a giant paleo-slide)

Rebesco M., Camerlenghi, A., Geletti, R., Canals, M., 2006. Margin architecture reveals the transition to the modern Antarctic Ice Sheet (AIS) at about 3 Ma, Geology, 34, 301–304.

Rebesco M., A. Camerlenghi, 2008, Late Pliocene margin development and mega debris flow deposits on the Antarctic continental margins: Evidence of the onset of the modern Antarctic Ice Sheet?, Palaeogeography, Palaeoclimatology, Palaeoecology, 260, 149-167 .

3) By comparison with Antarctic margins (Rebesco et al 2007; Rebesco and Camerlenghi, 2008), we infer that the first giant paleo-slide was produced by the mid-Pliocene initial growth of the ice sheet up to the shelf edge and the subsequent slides by cyclic late Pliocene-Pleistocene ice sheets advances.

2) Slides appear to be somehow related to recentmost glacial activity (Kveithola trough) and/or inter TMF areas (subgalcial water occurrence?)