Marine seismic survey area: Antarctic Ocean - Reflection seismic data

Working area: ANTARCTIC OCEAN

(1) Weddel Sea	(2) Ross Sea
BGR78 (Explora) 1978	BGR80 (Explora) 1980
BGR96 (Ak. Nemchinov) 1996
ANT.IV (Polarstern) 1986
ANT.VIII (Polarstern) 1990

Antarctic Ocean Source: BGR

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Cruise BGR78 1978

Vessel Explora

Weddel Sea

Multichannel seismic data acquisition parameters:

Total length of lines	12.063 km
Sampling rate	4 ms
Record length	6 000 ms
Streamer	digital - 48 channels

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Cruise BGR96 1996

Vessel Akademik Nemchinov

Weddel Sea

Multichannel seismic data acquisition parameters:

Total length of lines	3600 km
Sampling rate	4 ms
Record length	14 000 ms
Streamer

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Cruise ANT.IV/3 1986

Vessel Polarstern

Weddel Sea

Multichannel seismic data acquisition parameters:

Total length of lines	5756 km
Sampling rate	4 ms
Record length	10 000 ms
Streamer	digital - 48 channels

Summary 

On the "F.S. POLARSTERN" cruise ANT-IV/3 (6th December, 1985 - 13th March, 1986) multichannel seismic measurements were carried out in parallel with magnetic and gravimetric measurements on 33 lines with a total length of 6,263 km . 3,350 km of the multichannel seismic lines have been processed aboard. The geophysical studies were designed to investigate the structure and geological development of the Weddell Sea continental margin from meridians zero to 60°W, and to define suitable and safe drilling locations for Leg 113 of the Ocean Drilling Program.

The main results of the geophysical studies are:

• the discovery of an approximately N50°E trending failed drift basin, following the trend of a negative magnetic anomaly and a positive gravity anomaly; - the discovery of two extensive wedge-shaped and symmetric basement units around a failed drift basin between longitudes 40°W and 20°W. The seismic characteristics, i.e. seismic velocities of > 4 km/s and an internally divergent pattern of reflectors suggest that both wedges are formed from extrusive/intrusive volcanic rocks;
• the confirmation of a major plate tectonic boundary trending approximately N80°E to N60°E, i.e. the EXPLORA-ANDENES escarpment;
• the confirmation of a glaciogenic progradational wedge beneath the shelf of the Weddell Sea Embayment, made up of several thousand metres of sediments;
• the definition of 13 suitable and safe drilling locations for ODP-Leg 113.

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Cruise ANT.VIII 1990

Vessel Polarstern

Weddel Sea

Multichannel seismic data acquisition parameters:

Total length of lines	3.970 km
Sampling rate	4 ms
Record length	12 000 ms
Streamer	digital - 48 channels

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Cruise BGR80 1980

Vessel Explora

Ross Sea

Multichannel seismic data acquisition parameters:

Total length of lines	6.743 km
Sampling rate	4 ms
Record length	10 000 ms
Streamer	digital - 48 channels

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