RRS James Clark Ross JR20110825 (JR269A)
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS James Clark Ross (74JC) |
| Cruise identifier | JR20110825 (JR269A) |
| Cruise period | 2011-08-27 — 2011-09-05 |
| Status | Completed |
| Port of departure | Longyearbyen, Svalbard and Jan Mayen |
| Port of return | Longyearbyen, Svalbard and Jan Mayen |
| Purpose | Research |
| Objectives | The main goal of cruise JR269A was to use the Ifremer deep-towed low-frequency Chrip profile SYSIF and a high-resolution seismic reflection system to image gas transport structures and their geological setting beneath areas of active escape of methane gas into the ocean through the methane hydrate stability zone and at and close to the landward limit of the hydrate stability zone. These zones of gas escape were identified during RRS James Clark Ross cruise 211 in 2008 and have received further investigation during several subsequent cruises. Subsidiary goals were to determine in detail the seismic velocity structure of the regions imaged using ocean bottom seismometers, and to fully test the refurbished DASI deep-towed electromagnetic source by conducting a controlled source electromagnetic profile across three seabed electromagnetic recorders. Work was focused in two areas: a southern area close to the landward limit of the hydrate stability field, and a smaller northern area around a large pockmark on the Vestnesa Ridge sediment drift. The cruise was highly successful; the weather was very good, the ship performed well, and there was little downtime. Spectacular images were obtained with SYSIF and the high-resolution reflection system also performed well. Both survey areas revealed a great deal of complexity. |
| Chief scientist | Tim A Minshull (University of Southampton School of Ocean and Earth Science) |
| Coordinating body | Natural Environment Research Council (NERC) |
| Cruise report |  (7.09 MB) |
| Ocean/sea areas | |
| General | Greenland Sea |
| Specific | Greenland Sea |
| Track charts | (1.18 MB) |
| Measurements | |
| Physical oceanography | |
| CTD stations | Quantity: number of stations = 2 Description: CTD casts -To provide sound velocity structures for swath systems - Seabird's911plus CTD system measuring temperature and salinity and calculating sound velocity |
| Geology and geophysics | |
| Single-beam echosounding | Quantity: number of track lines = 170 Description: Simrad EK60 multi-frequency echosounder - to map gas plumes in water column |
| Multi-beam echosounding | Quantity: number of track lines = 179 Description: Kongsberg EM122 multibeam echosounder - seafloor mapping and mapping of gas plumes in water column |
| Single channel seismic reflection | Quantity: number of track lines = 57 Description: Topas PS15 sub-bottom profiler - To identify and characterise layers of sediment beneath the seafloor |
| Single channel seismic reflection | Quantity: number of profiles = 28 Description: SYSIF system: Deep towed seismic system for very high resolution survey - To image the shallow sedimentary structure with higher resolution than MCS reflection profiles |
| Multichannel seismic reflection | Quantity: number of profiles = 28 Description: Multi-channel seismic reflection profiles - source single GI gun (45cu.in/45cu.in.) - receicer: 60-channel streamer - To image the shallow sedimentary structure |
| Seismic refraction | Quantity: number of profiles = 2 Description: Wide-angle seismic profiles with SYSIF source recorded on ocean bottom seismometers |
| Seismic refraction | Quantity: number of profiles = 6 Description: Wide-angle seismic profiles with GI-gun source recorded on ocean bottom seismometers |
| Other geological/geophysical measurements | Quantity: number of profiles = 1 Description: DASI controlled source electromagnetic source recorded on OBEMs |
| Moorings, landers, buoys | |
| Geology and geophysics | |
| Multichannel seismic reflection | 78° 32' 45" N 9° 21' 38" E — Ocean Bottom seismometer (OBS01) - Depth: 468m Deployment time: 2011:241:11:34 - Recovery time: 2011:244:11:32 |
| Multichannel seismic reflection | 79° 0' 26" N 6° 54' 23" E — Ocean Bottom seismometer (OBS05) - Depth: 1207.30m Deployment time: 2011:245:09:45 - Recovery time: 2011:246:12:06 |
| Multichannel seismic reflection | 78° 32' 49" N 9° 22' 36" E — Ocean Bottom seismometer (OBS02) - Depth: 449m Deployment time: 2011:241:09:29 - Recovery time: 2011:244:08:45 |
| Multichannel seismic reflection | 78° 32' 33" N 9° 17' 4" E — Ocean Bottom seismometer (OBS04) - Depth: 504m Deployment time: 2011:241:11:34 - Recovery time: 2011:244:11:32 |
| Multichannel seismic reflection | 78° 32' 45" N 9° 21' 38" E — Ocean Bottom seismometer (OBS03) - Depth: 491m Deployment time: 2011:241:12:37 - Recovery time: 2011:244:10:40 |
| Multichannel seismic reflection | 78° 59' 44" N 6° 47' 25" E — Ocean Bottom seismometer (OBS08) - Depth: 1259.50m Deployment time: 2011:245:11:30 - Recovery time: 2011:246:10:48 |
| Seismic refraction | 79° 0' 26" N 6° 54' 23" E — Ocean Bottom seismometer (OBS05) - Depth: 1207.30m Deployment time: 2011:245:09:45 - Recovery time: 2011:246:12:06 |
| Seismic refraction | 78° 32' 33" N 9° 17' 4" E — Ocean Bottom seismometer (OBS04) - Depth: 504m Deployment time: 2011:241:11:34 - Recovery time: 2011:244:11:32 |
| Seismic refraction | 78° 32' 45" N 9° 21' 38" E — Ocean Bottom seismometer (OBS03) - Depth: 491m Deployment time: 2011:241:12:37 - Recovery time: 2011:244:10:40 |
| Seismic refraction | 78° 32' 49" N 9° 22' 36" E — Ocean Bottom seismometer (OBS02) - Depth: 449m Deployment time: 2011:241:09:29 - Recovery time: 2011:244:08:45 |
| Seismic refraction | 78° 32' 45" N 9° 21' 38" E — Ocean Bottom seismometer (OBS01) - Depth: 468m Deployment time: 2011:241:11:34 - Recovery time: 2011:244:11:32 |
| Seismic refraction | 78° 59' 44" N 6° 47' 25" E — Ocean Bottom seismometer (OBS08) - Depth: 1259.50m Deployment time: 2011:245:11:30 - Recovery time: 2011:246:10:48 |
| Magnetic measurements | 78° 36' 7" N 9° 5' 49" E — Ocean Bottom Electro-magnetometer (OBEM01) -Depth: 531m Deployment time: 2011:241:14:49 - Recovery time: 2011:244:14:17 |
| Magnetic measurements | 78° 36' 13" N 9° 7' 3" E — Ocean Bottom Electro-magnetometer (OBEM02) -Depth: 537.62m Deployment time: 2011:243:11:40 - Recovery time: 2011:247:15:18 |
| Magnetic measurements | 78° 36' 20" N 9° 8' 18" E — Ocean Bottom Electro-magnetometer (OBEM03) -Depth: 530m Deployment time: 2011:243:13:230 - Recovery time: 2011:247:16:20 |
