Cruise inventory

RRS Discovery D171

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS Discovery (74E3)
Cruise identifierD171
Cruise period1987-10-23 — 1987-11-27
StatusCompleted
Port of departureBarry, United Kingdom
Port of returnNassau, Bahamas
PurposeResearch
ObjectivesThe objectives of this cruise were to return to an area of the Mesozoic North Atlantic where an earlier reconnaissance multichannel seismic profile had imaged reflectors within the oceanic crust, and to make a detailed seismic survey of the area. In particular, we were to use two-ship expanding spread profiles (ESP's) to determine the velocity structure of the crust and hence to identify the main reflectors seen on normal incidence seismic reflection profiles.
We planned to work across a normal ribbon of oceanic crust and the adjacent small-offset Blake-Spur fracture zone so as to investigate the structure of both normal oceanic crust and fracture zone crust. We used two research ships each equipped with multichannel seismic systems, the RRS Discovery and RV Conrad. The project was run jointly between Cambridge and the University of Rhode Island.
Chief scientistRobert S White (University of Cambridge Department of Earth Sciences)
Cruise reportRRS Discovery D171 cruise report d171.pdf — access key 'C' (0.95 MB) 
Ocean/sea areas 
GeneralNorth West Atlantic Ocean (limit 40W)
Track chartsRRS Discovery D171 cruise track — trk3317.html RRS Discovery D171 cruise track — trk3317a.html
Measurements 
Physical oceanography 
BathythermographQuantity: number of profiles = 6
Geology and geophysics 
Multi-beam echosoundingQuantity: track kilometres = 4074
Single channel seismic reflectionQuantity: 400
Seismic refractionQuantity: track kilometres = 1111
Gravity measurementsQuantity: track kilometres = 4074
Magnetic measurementsQuantity: track kilometres = 4074