Sperus 7/77 Leg 7
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | Sperus (74TJ) |
| Cruise identifier | 7/77 Leg 7 |
| Cruise period | 1977-07-03 — 1977-07-15 |
| Status | Completed |
| Port of departure | South Shields, United Kingdom |
| Port of return | Lerwick, United Kingdom |
| Purpose | Research |
| Objectives | Geological and geophysical mapping of the UK Continental Shelf.
It was planned to survey in four areas with the following priority: 1. 1:250 000 Cormorant Sheet (61-62° N, 0-2° E). 2. West of Shetland in 1:250 000 Shetland Sheet (60-61° N, 2-0° W). 3. Additional data was required to complete interpretation of 1:250 000 Sutherland Sheet (58-59° N, 6-4° W). 4. 1:250 000 Halibut Bank Sheet (60-61° N, 0-2° E). Areas 1, 2 and 4 would be surveyed along a regular grid of lines - N-S at 13km spacing and E-W at 8km spacing. Areas 1 and 2 had top priority because these areas are programmed for sampling by Continental Shelf Unit North (CSU N) in 1978. After completion of areas 1 and 2, depending on time remaining, a decision would be made on whether or not to attempt survey of area 3. Three small additional survey jobs had been requested: a) A 250km sparker survey to clarify outcrop of base Upper Cretaceous in North Sea Quadrant 42 off the Yorkshire coast. b) A 300km regional survey extension east off Shetland between 60degN and 60deg20'N. c) A 300km gravity, magnetic and airgun survey to investigate a possible Tertiary igneous centre west of the Cormorant Sheet. A small sparker survey 300km was carried out in Quadrant 42 to provide shallow seismic data. Good pinger and echo-sounder records obtained in the Forties area. For surveying the sparker, airgun, side scan sonar, pinger, echo-sounder and magnetic equipment were used concurrently. An extension of the survey line was made over an area of a large magnetic anomaly. |
| Chief scientist | A Dobinson (Institute of Geological Sciences, Edinburgh) |
| Cruise report |  (18.20 MB) |
| Ocean/sea areas | |
| General | North Sea Norwegian Sea North East Atlantic Ocean (limit 40W) |
| Specific | North Sea |
| Track charts | (0.39 MB) (0.21 MB) (0.70 MB) |
| Measurements | |
| Geology and geophysics | |
| Single-beam echosounding | Description: regional geophysical survey |
| Long/short range side scan sonar | Description: regional geophysical survey |
| Long/short range side scan sonar | Description: format: seismic graphic recorder; regional geophysical survey |
| Single channel seismic reflection | Description: pinger.Format: seismic graphic recorde. Regional geophysical survey. |
| Multichannel seismic reflection | Description: wide angle reflection.Format: seismic graphic recorder. Regional geophysical survey |
| Seismic refraction | Quantity: track kilometres = 300 Description: small sparker survey |
| Gravity measurements | Description: format: seismic graphic recorder; regional geophysical survey |
| Magnetic measurements | Description: format: seismic graphic recorder; regional geophysical survey |
