RRS Shackleton S1/80
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS Shackleton (74SF) |
| Cruise identifier | S1/80 |
| Cruise period | 1979-12-30 — 1980-01-28 |
| Status | Completed |
| Port of departure | Bombay, India |
| Port of return | Karachi, Pakistan |
| Purpose | Research |
| Objectives | 1) Find the crustal structure and the depth to the Moho beneath the Gulf of Oman abyssal plain and the Makran accretionary wedge, to test whether the crust is oceanic or continental and whether it dips northward beneath the Makran.
2) Investigate three dimensional structure of the ridges and intervening basins on the continental Makran margin using a closely spaced grid of continuous seismic reflection panels. 3) Take heat flow measurements to constrain the age of the crust, which is otherwise unknown, and to assist in interpretation of the prominent gas hydrate- free gas reflectors found in the area. 4) Make a detailed seismic survey across a localised accumulation of gas to test whether it is trapped by a phase change to gas hydrate as had been previously postulated. 5) Continue the reconnaissance survey of the Makran margin eastwards to the plate triple junction near Karachi to see whether subduction deformation persisits along the entire coast. 6) Survey the Murray Ridge, a prominent feature of unkown origin, using seismic reflection profiles, and underway gravity, magnetic and bathymetric measurements. |
| Chief scientist | Keith E Louden (University of Cambridge Department of Earth Sciences) |
| Cruise report |  (0.62 MB) |
| Ocean/sea areas | |
| General | Gulf of Oman |
| Track charts |  |
| Measurements | |
| Physical oceanography | |
| Bathythermograph | Quantity: number of profiles = 4 |
| Other physical oceanographic measurements | Quantity: number of profiles = 1 Description: sound velocity station |
| Geology and geophysics | |
| Core - soft bottom | Quantity: number of cores = 4 Description: physical analysis of sediments |
| In-situ seafloor measurement/sampling | Quantity: number of measurements = 4 Description: sea floor temperature |
| Multi-beam echosounding | Quantity: track kilometres = 4444.8 |
| Single channel seismic reflection | Quantity: track kilometres = 4444.8 |
| Seismic refraction | Quantity: track kilometres = 370.4 |
| Gravity measurements | Quantity: track kilometres = 4444.8 |
| Magnetic measurements | Quantity: track kilometres = 4444.8 |
