RRS Discovery D118
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS Discovery (74E3) |
| Cruise identifier | D118 |
| Cruise period | 1981-02-16 — 1981-03-30 |
| Status | Completed |
| Port of departure | Gibraltar, Gibraltar |
| Port of return | Gibraltar, Gibraltar |
| Purpose | Research |
| Objectives | The 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 scientist | Tim J G Francis (Institute of Oceanographic Sciences Wormley Laboratory) |
| Coordinating body | by NEA,SWG |
| Cruise report |  (1.31 MB) |
| Ocean/sea areas | |
| General | North Atlantic Ocean |
| Specific | North Atlantic |
| Track charts |  |
| Measurements | |
| Meteorology | |
| Routine standard measurements | |
| Geology and geophysics | |
| Dredge | Quantity: number of hauls = 3 |
| Core - soft bottom | Quantity: number of cores = 16 Description: 6 physical analysis;paleontology;mineral resources |
| Bottom photography | Quantity: number of deployments = 3 |
| Single-beam echosounding | Quantity: track kilometres = 9667.44 |
| Single channel seismic reflection | Quantity: track kilometres = 907.48 |
| Seismic refraction | Quantity: number of deployments = 7 Description: ocean bottom seismographs |
| Gravity measurements | Quantity: track kilometres = 9667.44 |
| Magnetic measurements | Quantity: track kilometres = 9445.2 |
| Other geological/geophysical measurements | Quantity: track kilometres = 8556.24 Description: 2 kHz high resolution sub-bottom profiles |
| Other geological/geophysical measurements | Quantity: number of measurements = 8 Description: magnetic susceptibil.cont.along the length of 8 soft sediment cores |
| Other geological/geophysical measurements | Quantity: number of measurements = 3 Description: heat flow |
