RRS Shackleton S4/75
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS Shackleton (74SF) |
| Cruise identifier | S4/75 |
| Cruise period | 1975-04-18 — 1975-05-07 |
| Status | Completed |
| Port of departure | Dubai, United Arab Emirates |
| Port of return | Bombay, India |
| Purpose | Research |
| Objectives | 1. Geophysical study of the Owen Basin
The main objective was to establish the nature and origin of the crust beneath the Owen Basin and to gain some insight into the age of the crust, since it is possible that its history goes back to the break-up of Gondwanaland. It was also planned to relate the deeper reflectors seen beneath the basin to those uplifted on the Owen Ridge which have already been sampled in holes drilled by D.V. Glomar Challenger. The chain of seamounts along the Owen Basin/Sheba Ridge boundary were also to be studied. 2. Organic geochemistry of recent sediments Three cores were planned at different depths on the continental margin off Masirah Bay to expand the current studies of upwelling regions being undertaken at IOS Wormley. 3. Other geological samling Dredging of the escarpment at the south end of the Owen Ridge and coring across a leveed channel on the Indus Cone were subsidiary objectives of Cruise 4/75. 4. On-line digital processing of seismic profiles It was planned to develop at sea simple algorithms for an on-line signal processing system designed to enhance the penetration of seismic reflection profiles. |
| Chief scientist | Robert B Whitmarsh (Institute of Oceanographic Sciences Wormley Laboratory) |
| Cruise report |  (4.90 MB) (0.85 MB) |
| Ocean/sea areas | |
| General | Gulf of Iran (Persian Gulf) Arabian Sea Gulf of Oman |
| Track charts |  |
| Measurements | |
| Geology and geophysics | |
| Core - soft bottom | Quantity: number of cores = 4 |
| Long/short range side scan sonar | Quantity: track kilometres = 4630 |
| Seismic refraction | Quantity: 80 |
| Gravity measurements | Quantity: track kilometres = 5000 |
| Magnetic measurements | Quantity: track kilometres = 5000 |
