Cruise inventory

RRS James Clark Ross JR20110825 (JR269A)

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS James Clark Ross (74JC)
Cruise identifierJR20110825 (JR269A)
Cruise period2011-08-27 — 2011-09-05
StatusCompleted
Port of departureLongyearbyen, Svalbard and Jan Mayen
Port of returnLongyearbyen, Svalbard and Jan Mayen
PurposeResearch
ObjectivesThe 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 scientistTim A Minshull (University of Southampton School of Ocean and Earth Science)
Coordinating bodyNatural Environment Research Council (NERC)
Cruise reportRRS James Clark Ross JR20110825 (JR269A) cruise report jr269a.pdf — access key 'C' (7.09 MB) 
Ocean/sea areas 
GeneralGreenland Sea
SpecificGreenland Sea
Track chartsRRS James Clark Ross JR20110825 (JR269A) cruise track — jr269atrk.pdf (00 MB) 
Measurements 
Physical oceanography 
CTD stationsQuantity: 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 echosoundingQuantity: number of track lines = 170
Description: Simrad EK60 multi-frequency echosounder - to map gas plumes in water column
Multi-beam echosoundingQuantity: number of track lines = 179
Description: Kongsberg EM122 multibeam echosounder - seafloor mapping and mapping of gas plumes in water column
Single channel seismic reflectionQuantity: 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
Single channel seismic reflectionQuantity: number of track lines = 57
Description: Topas PS15 sub-bottom profiler - To identify and characterise layers of sediment beneath the seafloor
Multichannel seismic reflectionQuantity: 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 refractionQuantity: number of profiles = 2
Description: Wide-angle seismic profiles with SYSIF source recorded on ocean bottom seismometers
Seismic refractionQuantity: number of profiles = 6
Description: Wide-angle seismic profiles with GI-gun source recorded on ocean bottom seismometers
Other geological/geophysical measurementsQuantity: number of profiles = 1
Description: DASI controlled source electromagnetic source recorded on OBEMs
Moorings, landers, buoys 
Geology and geophysics 
Multichannel seismic reflection78° 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 reflection79° 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 reflection78° 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 reflection78° 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 reflection78° 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 reflection78° 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 refraction79° 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 refraction78° 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 refraction78° 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 refraction78° 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 refraction78° 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 refraction78° 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 measurements78° 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 measurements78° 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 measurements78° 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