Cruise inventory

Sperus 7/77 Leg 7

Cruise summary report

Cruise Info. 
Ship name (ship code)Sperus (74TJ)
Cruise identifier7/77 Leg 7
Cruise period1977-07-03 — 1977-07-15
StatusCompleted
Port of departureSouth Shields, United Kingdom
Port of returnLerwick, United Kingdom
PurposeResearch
ObjectivesGeological 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 scientistA Dobinson (Institute of Geological Sciences, Edinburgh)
Cruise reportSperus 7/77 Leg 7 cruise report sperus7_77.pdf — access key 'C' (18.20 MB) 
Ocean/sea areas 
GeneralNorth Sea
Norwegian Sea
North East Atlantic Ocean (limit 40W)
SpecificNorth Sea
Track chartsSperus 7/77 Leg 7 cruise track — sperus7_77_geology.pdf (00 MB)  Sperus 7/77 Leg 7 cruise track — sperus7_77_lines1-10.pdf (00 MB)  Sperus 7/77 Leg 7 cruise track — sperus7_77_lines12-108.pdf (00 MB) 
Measurements 
Geology and geophysics 
Single-beam echosoundingDescription: regional geophysical survey
Long/short range side scan sonarDescription: regional geophysical survey
Long/short range side scan sonarDescription: format: seismic graphic recorder; regional geophysical survey
Single channel seismic reflectionDescription: pinger.Format: seismic graphic recorde. Regional geophysical survey.
Multichannel seismic reflectionDescription: wide angle reflection.Format: seismic graphic recorder. Regional geophysical survey
Seismic refractionQuantity: track kilometres = 300
Description: small sparker survey
Gravity measurementsDescription: format: seismic graphic recorder; regional geophysical survey
Magnetic measurementsDescription: format: seismic graphic recorder; regional geophysical survey