RRS Discovery D118

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS Discovery (74E3)
Cruise identifierD118
Cruise period1981-02-16 — 1981-03-30
Port of departureGibraltar, Gibraltar
Port of returnGibraltar, Gibraltar
ObjectivesThe primary objective of the cruise was to make geological and geophysical studies of the ocean floor over a wide range of sedimentary environments, plate ages and geographic latitudes - part of the feasibility studies into the ocean disposal of high-level radioactive waste commissioned by the Department of the Environment. To this end the bulk of the work carried out was aimed at understanding the processes affecting the sediments. The work was concentrated in four study areas: Great Meteor East and West, Cape Verde One and King's Trough Flank. Detailed objectives were as follows:
(a) Gravity and Kastenlot coring for stratigraphic and geotechnical study.
(b) Temperature/Thermal Conductivity measurements in the top 5m of sediment by the "pogo-stick" method in order to observe lateral variability of heat flow and the extent of non-linear temperature gradients.
(c) Bottom photography with a new survey camera system to observe sedimentary features, a glacial erratic distribution and extent of biological activity.
(d) Testing of a new High-Resolution Near-Bottom Profiler on the CTD wire, operating in the frequency band 5-10 kHz.
(e) Dredging for glacial erratic material with the IOS Epibenthic Sledge.
(f) Small Scale Seismic Experiment with PUBS and OBS designed to test a number of explosive and non-explosive bottom sources. If successful the experiment would throw light on the in-situ properties of the unlithified sedimentary layer.
(g) OBS observations along the line of the Oceanographer Fracture Zone to determine whether the low level of intraplate seismicity within the ocean basins is associated with such features.
(h) Underway geophysical observations including precision echo-sounding, (10 kHz), magnetics, gravity, single-channel SRP with airgun and 2 kHz high-resolution profiling.
Chief scientistTim J G Francis (Institute of Oceanographic Sciences Wormley Laboratory)
Coordinating bodyby NEA,SWG
Cruise reportRRS Discovery D118 cruise report d118.pdf (1.31 MB) 
Ocean/sea areas 
GeneralNorth Atlantic Ocean
SpecificNorth Atlantic
Track chartsRRS Discovery D118 cruise track — trk2605.html RRS Discovery D118 cruise track — trk2605b.html
Routine standard measurements
Geology and geophysics 
DredgeQuantity: number of hauls = 3
Core - soft bottomQuantity: number of cores = 16
Description: 6 physical analysis;paleontology;mineral resources
Bottom photographyQuantity: number of deployments = 3
Single-beam echosoundingQuantity: track kilometres = 9667.44
Single channel seismic reflectionQuantity: track kilometres = 907.48
Seismic refractionQuantity: number of deployments = 7
Description: ocean bottom seismographs
Gravity measurementsQuantity: track kilometres = 9667.44
Magnetic measurementsQuantity: track kilometres = 9445.2
Other geological/geophysical measurementsQuantity: track kilometres = 8556.24
Description: 2 kHz high resolution sub-bottom profiles
Other geological/geophysical measurementsQuantity: number of measurements = 3
Description: heat flow
Other geological/geophysical measurementsQuantity: number of measurements = 8
Description: magnetic susceptibil.cont.along the length of 8 soft sediment cores