RRS John Murray JM3/70 Leg 2
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS John Murray (74MJ) |
| Cruise identifier | JM3/70 Leg 2 |
| Cruise period | 1970-04-04 — 1970-04-13 |
| Status | Completed |
| Port of departure | Cork, Ireland |
| Port of return | Barry, United Kingdom |
| Purpose | Research |
| Objectives | The main purpose of the cruise was to survey by seismic, gravity and magnetic methods the ares to the south west of Ireland leading across the shelf to the Porcupine Seabight and the continental margin. Seismic refraction lines were required to provide information of the shallow layers.
Additional experiments were planned: 1. the evaluation of a vertical hydrophone array for use in water of oceanic depths 2. the evaluation of aquaflex as a seismic source for refraction measurements at sea using sono-buoys 3. geophysical traverses across the Nymphe Bank and Bristol Channel 4. a gravity traverse into Carmarthen Bay 5. evaluation of effect of ship's magnetic field on proton magnetometer towed at various lengths and headings 6. bottom sampling for foraminifera and ostracoda in the River Shannon estauary |
| Chief scientist | Derek J Blundell (University of Birmingham Department of Geology with Geophysics) |
| Cruise report |  (0.41 MB) |
| Ocean/sea areas | |
| General | Celtic Sea |
| Specific | Celtic Sea |
| Track charts | (0.02 MB) |
| Measurements | |
| Physical oceanography | |
| Other physical oceanographic measurements | Quantity: number of stations = 10 Description: seawater samples |
| Biology and fisheries | |
| Phytoplankton | Quantity: number of stations = 10 Description: plankton sampling |
| Zooplankton | Quantity: number of stations = 10 Description: plankton sampling |
| Geology and geophysics | |
| Grab | Quantity: number of stations = 10 Description: shipek grab for sediment samples |
| Seismic refraction | Quantity: number of surveys = 3 Description: sonobouy seismic refraction lines |
| Gravity measurements | Quantity: number of surveys = 8 Description: gravity/magnetic traverses |
| Magnetic measurements | Quantity: number of surveys = 8 Description: gravity/magnetic traverses |
| Other geological/geophysical measurements | Quantity: number of surveys = 2 Description: sparker used on traverses 70/14 and 70/16 |
| Other geological/geophysical measurements | Description: P.D.R recordings made continuously |
